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Life, global temperature and entropy
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Vend
Jun 14, 2012, 1:25:10 PM6/14/12
to
I've found some arguments, from theoretical physicists, that claim
that the existence of life on earth, and the workings of natural
selection, can be explained in the framework of non-equilibrium
thermodynamics.
For instance: http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.0050142
I've not read that thoroughly, and I believe that the topic has been
already discussed here but I didn't followed that very much.
Intuitively I'm a bit wary of these kind of arguments that
superficially seem simplistic and almost teleological.
Anyway, their point seems to be that complex systems far from
thermodynamic equilibrium (such as the earth surface with its
biosphere) tend to obey a so called "maximum entropy production" or
"maximum entropy rate" principle: they system tends to a state that
maximizes the rate at which entropy is expelled to the surrounding
environment (e.g. by radiating long wavelength photons to space).
My first question is:
- A lifeless earth would still radiate the same amount of energy to
space. But would it do so at an higher temperature, thus emitting
shorter wavelength (less entropic) photons?
IIUC, after photosynthesis appeared and the atmosphere became
chemically oxidizing, some greenhouse gasses like methane couldn't
exist in significant concentrations and thus the temperature become
lower. Is that correct? Did life also worked to remove CH4 and CO2
from the atmosphere even before photosynthetic bacteria started
flooding it with oxygen?
My second question is:
- Is the Maximum Entropy Production principle a reasonable explanation
(in a reductionist sense) for abiogenesis and biological evolution?
that the existence of life on earth, and the workings of natural
selection, can be explained in the framework of non-equilibrium
thermodynamics.
For instance: http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.0050142
I've not read that thoroughly, and I believe that the topic has been
already discussed here but I didn't followed that very much.
Intuitively I'm a bit wary of these kind of arguments that
superficially seem simplistic and almost teleological.
Anyway, their point seems to be that complex systems far from
thermodynamic equilibrium (such as the earth surface with its
biosphere) tend to obey a so called "maximum entropy production" or
"maximum entropy rate" principle: they system tends to a state that
maximizes the rate at which entropy is expelled to the surrounding
environment (e.g. by radiating long wavelength photons to space).
My first question is:
- A lifeless earth would still radiate the same amount of energy to
space. But would it do so at an higher temperature, thus emitting
shorter wavelength (less entropic) photons?
IIUC, after photosynthesis appeared and the atmosphere became
chemically oxidizing, some greenhouse gasses like methane couldn't
exist in significant concentrations and thus the temperature become
lower. Is that correct? Did life also worked to remove CH4 and CO2
from the atmosphere even before photosynthetic bacteria started
flooding it with oxygen?
My second question is:
- Is the Maximum Entropy Production principle a reasonable explanation
(in a reductionist sense) for abiogenesis and biological evolution?
Richard Norman
Jun 14, 2012, 2:46:18 PM6/14/12
to
On Thu, 14 Jun 2012 10:25:10 -0700 (PDT), Vend <ven...@virgilio.it>
wrote:
I now have the article but have only skimmed it, not read it
carefully. Of course that doesn't stop me from having opinions. It
certainly looks like physicists doing their thing, making grandiose
pronouncements about things they really have no understanding of.
It would be interesting to hear a theory about why, if life is so
effective at maximizing entropy production, it should be so rare in
our own solar system. Why don't Venus and Mars, not to mention the
moons of Jupiter and Saturn, strive to do better?
wrote:
carefully. Of course that doesn't stop me from having opinions. It
certainly looks like physicists doing their thing, making grandiose
pronouncements about things they really have no understanding of.
It would be interesting to hear a theory about why, if life is so
effective at maximizing entropy production, it should be so rare in
our own solar system. Why don't Venus and Mars, not to mention the
moons of Jupiter and Saturn, strive to do better?
Vend
Jun 14, 2012, 6:52:46 PM6/14/12
to
or it wouldn't help maximizing entropy production. Not very much
falsifiable, but I presume it might be plausible that the probability
of abiogenesis in any given environment is either very close to 1 or
very close to 0, depending on the environment.
Anyway, do you think it is true that life on earth increases entropy
emission? Are there any other plausible non-living processes that
could increase entropy production more than life (e.g. runaway
polymerization that removes all the carbon from the atmosphere
converting it in a dense tar that sinks to the bottom of the ocean)?
Richard Norman
Jun 14, 2012, 9:48:29 PM6/14/12
to
On Thu, 14 Jun 2012 15:52:46 -0700 (PDT), Vend <ven...@virgilio.it>
The paper is a confusing mix of disparate ideas. For example, it
talks of increased diversity in an ecosystem as increasing entropy.
That is true using an entropic or Shannon measure of diversity.
However it is not by any means clear that the "informational" value of
entropy is at all commensurate with the thermodynamic notion of
entropy as energy flows through the ecosystem. My guess is that, if
you tried to express the information value of diversity in physical
terms (what are the units for entropy by the way, J/K?), it would be
an incredibly tiny fraction of the actual flow of Joules through the
system (divided by the temperature of the system).
The paper claims a pond full of organisms generates more entropy than
bare rock. I doubt it. My guess is that a field of black basalt in
the sun absorbs far more energy, converting high "quality" sunlight
into low quality heat, than does any biological system. Plants only
use perhaps 5% of the energy that falls on them. Basalt has an albedo
of 0.11, absorbing 89% of the light energy that falls on it.
talks of increased diversity in an ecosystem as increasing entropy.
That is true using an entropic or Shannon measure of diversity.
However it is not by any means clear that the "informational" value of
entropy is at all commensurate with the thermodynamic notion of
entropy as energy flows through the ecosystem. My guess is that, if
you tried to express the information value of diversity in physical
terms (what are the units for entropy by the way, J/K?), it would be
an incredibly tiny fraction of the actual flow of Joules through the
system (divided by the temperature of the system).
The paper claims a pond full of organisms generates more entropy than
bare rock. I doubt it. My guess is that a field of black basalt in
the sun absorbs far more energy, converting high "quality" sunlight
into low quality heat, than does any biological system. Plants only
use perhaps 5% of the energy that falls on them. Basalt has an albedo
of 0.11, absorbing 89% of the light energy that falls on it.
marc.t...@wanadoo.fr
Jun 15, 2012, 4:33:49 AM6/15/12
to
On Jun 14, 7:25 pm, Vend <ven...@virgilio.it> wrote:
> I've found some arguments, from theoretical physicists, that claim
> that the existence of life on earth, and the workings of natural
> selection, can be explained in the framework of non-equilibrium
> thermodynamics.
I thank you very much for this exciting discovery.
> I've found some arguments, from theoretical physicists, that claim
> that the existence of life on earth, and the workings of natural
> selection, can be explained in the framework of non-equilibrium
> thermodynamics.
> For instance:http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.0050142
> I've not read that thoroughly, and I believe that the topic has been
> already discussed here but I didn't followed that very much.
> Intuitively I'm a bit wary of these kind of arguments that
> superficially seem simplistic and almost teleological.
main idea is based on statistical theory and thus on "the most
probable way for the molecules in a system to arrange themselves".
> Anyway, their point seems to be that complex systems far from
> thermodynamic equilibrium (such as the earth surface with its
> biosphere) tend to obey a so called "maximum entropy production" or
> "maximum entropy rate" principle: they system tends to a state that
> maximizes the rate at which entropy is expelled to the surrounding
> environment (e.g. by radiating long wavelength photons to space).
> My first question is:
> - A lifeless earth would still radiate the same amount of energy to
> space. But would it do so at an higher temperature, thus emitting
> shorter wavelength (less entropic) photons?
higher greenhouse effect and thus radiated less heat to space.
> IIUC, after photosynthesis appeared and the atmosphere became
> chemically oxidizing, some greenhouse gasses like methane couldn't
> exist in significant concentrations and thus the temperature become
> lower. Is that correct? Did life also worked to remove CH4 and CO2
> from the atmosphere even before photosynthetic bacteria started
> flooding it with oxygen?
> My second question is:
> - Is the Maximum Entropy Production principle a reasonable explanation
> (in a reductionist sense) for abiogenesis and biological evolution?
and how evolution emerged about 4 billion years ago.
I recommend you to read the paper by Hoelzer et al. (2006).
Reference:
Hoelzer GA, Smith E, Pepper JW. 2006. On the logical relationship
between natural selection and self-organization. J Evolution Biol
19:1785-1794.
marc.t...@wanadoo.fr
Jun 15, 2012, 4:36:29 AM6/15/12
to
On Jun 15, 3:48 am, Richard Norman <r_s_nor...@comcast.net> wrote:
> The paper is a confusing mix of disparate ideas. For example, it
> talks of increased diversity in an ecosystem as increasing entropy.
> That is true using an entropic or Shannon measure of diversity.
> However it is not by any means clear that the "informational" value of
> entropy is at all commensurate with the thermodynamic notion of
> entropy as energy flows through the ecosystem. My guess is that, if
> you tried to express the information value of diversity in physical
> terms (what are the units for entropy by the way, J/K?), it would be
> an incredibly tiny fraction of the actual flow of Joules through the
> system (divided by the temperature of the system).
>
> The paper claims a pond full of organisms generates more entropy than
> bare rock. I doubt it. My guess is that a field of black basalt in
> the sun absorbs far more energy, converting high "quality" sunlight
> into low quality heat, than does any biological system. Plants only
> use perhaps 5% of the energy that falls on them. Basalt has an albedo
> of 0.11, absorbing 89% of the light energy that falls on it.
I recognize your openness.
> The paper is a confusing mix of disparate ideas. For example, it
> talks of increased diversity in an ecosystem as increasing entropy.
> That is true using an entropic or Shannon measure of diversity.
> However it is not by any means clear that the "informational" value of
> entropy is at all commensurate with the thermodynamic notion of
> entropy as energy flows through the ecosystem. My guess is that, if
> you tried to express the information value of diversity in physical
> terms (what are the units for entropy by the way, J/K?), it would be
> an incredibly tiny fraction of the actual flow of Joules through the
> system (divided by the temperature of the system).
>
> The paper claims a pond full of organisms generates more entropy than
> bare rock. I doubt it. My guess is that a field of black basalt in
> the sun absorbs far more energy, converting high "quality" sunlight
> into low quality heat, than does any biological system. Plants only
> use perhaps 5% of the energy that falls on them. Basalt has an albedo
> of 0.11, absorbing 89% of the light energy that falls on it.
Vend
Jun 15, 2012, 6:27:36 AM6/15/12
to
On 15 Giu, 10:33, marc.tess...@wanadoo.fr wrote:
> On Jun 14, 7:25 pm, Vend <ven...@virgilio.it> wrote:> I've found some arguments, from theoretical physicists, that claim
> > that the existence of life on earth, and the workings of natural
> > selection, can be explained in the framework of non-equilibrium
> > thermodynamics.
>
> I thank you very much for this exciting discovery.
>
> > For instance:http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.0050142
> > I've not read that thoroughly, and I believe that the topic has been
> > already discussed here but I didn't followed that very much.
> > Intuitively I'm a bit wary of these kind of arguments that
> > superficially seem simplistic and almost teleological.
>
> I don't think there is any teleological ideology behind because the
> main idea is based on statistical theory and thus on "the most
> probable way for the molecules in a system to arrange themselves".
In order to make arguments from maximum probability, you need a
> On Jun 14, 7:25 pm, Vend <ven...@virgilio.it> wrote:> I've found some arguments, from theoretical physicists, that claim
> > that the existence of life on earth, and the workings of natural
> > selection, can be explained in the framework of non-equilibrium
> > thermodynamics.
>
> I thank you very much for this exciting discovery.
>
> > For instance:http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.0050142
> > I've not read that thoroughly, and I believe that the topic has been
> > already discussed here but I didn't followed that very much.
> > Intuitively I'm a bit wary of these kind of arguments that
> > superficially seem simplistic and almost teleological.
>
> I don't think there is any teleological ideology behind because the
> main idea is based on statistical theory and thus on "the most
> probable way for the molecules in a system to arrange themselves".
process that quickly explores the phase space. A pot of water on a
stove can reasonably reach the macrostate corresponding to the largest
number of microstates by brute-force random search. It's not
intuitively clear to me that life can do the same, given the size of
the configuration space.
> There is the case of Venus (a kind of "lifeless earth") which had a
> higher greenhouse effect and thus radiated less heat to space.
space. As long as the average surface temperature stays approximately
constant, the incoming heat (solar and geothermal) must be equal to
the radiated heat.
However, the more greenhouse effect, the higher the average surface
temperature is. Higher temperature results in radiated photons of
lower average wavelength and thus lower entropy.
> The first bacteria were likely methane-utilizing ones.
occourring soluble organic chemicals.
> Personally I am quite seduced by the idea that MEP would explain why
> and how evolution emerged about 4 billion years ago.
> I recommend you to read the paper by Hoelzer et al. (2006).
>
> Reference:
> Hoelzer GA, Smith E, Pepper JW. 2006. On the logical relationship
> between natural selection and self-organization. J Evolution Biol
> 19:1785-1794.
marc.t...@wanadoo.fr
Jun 15, 2012, 6:58:58 AM6/15/12
to
On Jun 15, 12:27 pm, Vend <ven...@virgilio.it> wrote:
> In order to make arguments from maximum probability, you need a
> process that quickly explores the phase space. A pot of water on a
> stove can reasonably reach the macrostate corresponding to the largest
> number of microstates by brute-force random search. It's not
> intuitively clear to me that life can do the same, given the size of
> the configuration space.
In the paper it is specified: "Evolution, Bejan believes, has been a
> In order to make arguments from maximum probability, you need a
> process that quickly explores the phase space. A pot of water on a
> stove can reasonably reach the macrostate corresponding to the largest
> number of microstates by brute-force random search. It's not
> intuitively clear to me that life can do the same, given the size of
> the configuration space.
process whereby structures have remodeled themselves so that energy
and matter flow through them as quickly and efficiently as possible.
Better flow structures—be they animals or river networks—have replaced
poorer".
What do you think of this interesting approach?
> > There is the case of Venus (a kind of "lifeless earth") which had a
> > higher greenhouse effect and thus radiated less heat to space.
>
> The greenhouse effect doesn't reduce the amount of heat radiated to
> space. As long as the average surface temperature stays approximately
> constant, the incoming heat (solar and geothermal) must be equal to
> the radiated heat.
> However, the more greenhouse effect, the higher the average surface
> temperature is. Higher temperature results in radiated photons of
> lower average wavelength and thus lower entropy.
> > The first bacteria were likely methane-utilizing ones.
> I think that the very first bacteria just used spontaneously
When you speak of "organic chemicals" what do you mean exactly? Do you
mean chemicals produced by other organisms than the very first
bacteria?
Ernest Major
Jun 15, 2012, 7:02:10 AM6/15/12
to
In message
<1deae64f-6a03-4af6...@m10g2000vbn.googlegroups.com>,
Vend <ven...@virgilio.it> writes
entropy generation.
However, it's a bit more complicated. The greenhouse effect does
increase the surface temperature, but it lowers the temperature in the
atmosphere at sufficient altitude (see stratospheric cooling). I suspect
that the contribution from radiation directly to space dominates over
the contribution from reradiation from high in the atmosphere, but I
could be wrong.
--
alias Ernest Major
<1deae64f-6a03-4af6...@m10g2000vbn.googlegroups.com>,
Vend <ven...@virgilio.it> writes
>The greenhouse effect doesn't reduce the amount of heat radiated to
>space. As long as the average surface temperature stays approximately
>constant, the incoming heat (solar and geothermal) must be equal to the
>radiated heat. However, the more greenhouse effect, the higher the
>average surface temperature is. Higher temperature results in radiated
>photons of lower average wavelength and thus lower entropy.
In which case, life, by removing CO2 from the atmosphere, would increase
>space. As long as the average surface temperature stays approximately
>constant, the incoming heat (solar and geothermal) must be equal to the
>radiated heat. However, the more greenhouse effect, the higher the
>average surface temperature is. Higher temperature results in radiated
>photons of lower average wavelength and thus lower entropy.
entropy generation.
However, it's a bit more complicated. The greenhouse effect does
increase the surface temperature, but it lowers the temperature in the
atmosphere at sufficient altitude (see stratospheric cooling). I suspect
that the contribution from radiation directly to space dominates over
the contribution from reradiation from high in the atmosphere, but I
could be wrong.
--
alias Ernest Major
marc.t...@wanadoo.fr
Jun 15, 2012, 7:34:10 AM6/15/12
to
On Jun 15, 12:27 pm, Vend <ven...@virgilio.it> wrote:
> The greenhouse effect doesn't reduce the amount of heat radiated to
> space. As long as the average surface temperature stays approximately
> constant, the incoming heat (solar and geothermal) must be equal to
> the radiated heat.
> However, the more greenhouse effect, the higher the average surface
> temperature is. Higher temperature results in radiated photons of
> lower average wavelength and thus lower entropy.
I suppose the fact that the average surface temperature increase (due
> space. As long as the average surface temperature stays approximately
> constant, the incoming heat (solar and geothermal) must be equal to
> the radiated heat.
> However, the more greenhouse effect, the higher the average surface
> temperature is. Higher temperature results in radiated photons of
> lower average wavelength and thus lower entropy.
to the greenhouse effect) results in radiated photons of lower average
wavelength (then in a higher amount of heat radiated by Earth to
space) is according to the black-body radiation mechanism?
When you say that this results in lower entropy, which entropy are you
speaking of:? Earth surface entropy or exporting entropy to space?
marc.t...@wanadoo.fr
Jun 15, 2012, 8:37:07 AM6/15/12
to
ISTM the claim is according to the second law of thermodynamics: to
create and maintain many complex systems (organisms) representing a
low entropy level, a big amount of entropy must be generated by the
organisms in comparison to the thermodynamic state of a field of black
basalt (high initial entropy level).
Richard Norman
Jun 15, 2012, 9:28:13 AM6/15/12
to
On Fri, 15 Jun 2012 05:37:07 -0700 (PDT), marc.t...@wanadoo.fr
wrote:
What the paper actually claims is "Adding life to physical systems
certainly increases entropy production. A pond full of plankton or a
patch of grass absorbs more of the Sun’s energy, and so produces more
entropy, than a sterile pool or bare rock." I claim that a patch of
black basalt absorbs more of the Sun's energy than a patch of grass.
The real difference is that a pond full of plankton or a patch of
grass convert the energy of sunlight into heat in a far more indrect
way than does a sterile pool or bare rock. But thermodynamics in this
application considers the end points of a process, not the pathway to
reach the end point. In both the living and the non-living cases,
virtually all the absorbed energy is ultimately converted into heat.
The amount of energy used in a living ecosystem in virtual steady
state to produce "structure" or "order" or diversity is trivial. So
the entropy change is the energy absorbed divided by the temperature
of the final heat. The energy absorbed from the sun by the biosphere
is photosynthesis: at most 8% of the incident radiation. All the rest
of the light falling on grass or pond that is not reflected goes
directly to heat, just as it does on the sterile pool or rock. The
temperature of grass or pond might be lower than that of a sterile
pool or rock but perhaps by 10 or even 15 degrees C, that is just 5%
lower. So do the math: there is no way that it works.
If you disagree, I would like to see the numbers, not just statements
of "complexity" or "increased structure and diversity".
You might argue that the world is not made of dark basalt but rather
of lighter silicon dioxide or granites. In that case my question is
why didn't "physical evolution" produce a dark basaltic world rather
than a rather lighter colored biosphere because that would produce an
even greater entropy production: the living world is not maximum.
wrote:
certainly increases entropy production. A pond full of plankton or a
patch of grass absorbs more of the Sun’s energy, and so produces more
entropy, than a sterile pool or bare rock." I claim that a patch of
black basalt absorbs more of the Sun's energy than a patch of grass.
The real difference is that a pond full of plankton or a patch of
grass convert the energy of sunlight into heat in a far more indrect
way than does a sterile pool or bare rock. But thermodynamics in this
application considers the end points of a process, not the pathway to
reach the end point. In both the living and the non-living cases,
virtually all the absorbed energy is ultimately converted into heat.
The amount of energy used in a living ecosystem in virtual steady
state to produce "structure" or "order" or diversity is trivial. So
the entropy change is the energy absorbed divided by the temperature
of the final heat. The energy absorbed from the sun by the biosphere
is photosynthesis: at most 8% of the incident radiation. All the rest
of the light falling on grass or pond that is not reflected goes
directly to heat, just as it does on the sterile pool or rock. The
temperature of grass or pond might be lower than that of a sterile
pool or rock but perhaps by 10 or even 15 degrees C, that is just 5%
lower. So do the math: there is no way that it works.
If you disagree, I would like to see the numbers, not just statements
of "complexity" or "increased structure and diversity".
You might argue that the world is not made of dark basalt but rather
of lighter silicon dioxide or granites. In that case my question is
why didn't "physical evolution" produce a dark basaltic world rather
than a rather lighter colored biosphere because that would produce an
even greater entropy production: the living world is not maximum.
Vend
Jun 15, 2012, 10:25:35 AM6/15/12
to
On 15 Giu, 13:34, marc.tess...@wanadoo.fr wrote:
> On Jun 15, 12:27 pm, Vend <ven...@virgilio.it> wrote:> The greenhouse effect doesn't reduce the amount of heat radiated to
> > space. As long as the average surface temperature stays approximately
> > constant, the incoming heat (solar and geothermal) must be equal to
> > the radiated heat.
> > However, the more greenhouse effect, the higher the average surface
> > temperature is. Higher temperature results in radiated photons of
> > lower average wavelength and thus lower entropy.
>
> I suppose the fact that the average surface temperature increase (due
> to the greenhouse effect) results in radiated photons of lower average
> wavelength (then in a higher amount of heat radiated by Earth to
> space) is according to the black-body radiation mechanism?
That is what I was thinking of. Of course, the Earth also radiates
> On Jun 15, 12:27 pm, Vend <ven...@virgilio.it> wrote:> The greenhouse effect doesn't reduce the amount of heat radiated to
> > space. As long as the average surface temperature stays approximately
> > constant, the incoming heat (solar and geothermal) must be equal to
> > the radiated heat.
> > However, the more greenhouse effect, the higher the average surface
> > temperature is. Higher temperature results in radiated photons of
> > lower average wavelength and thus lower entropy.
>
> I suppose the fact that the average surface temperature increase (due
> to the greenhouse effect) results in radiated photons of lower average
> wavelength (then in a higher amount of heat radiated by Earth to
> space) is according to the black-body radiation mechanism?
sunlight reflectively, depending on the albedo of it's surface and
atmosphere. I don't know whether life contributes positively or
negatively to the Earth albedo.
The Earth albedo is higher than the albedo of the Moon or Mars,
largely due to the presence of clouds, snow and large ice caps.
According to Wikipedia the albedo of forests, grasslands and bare soil
is lower than desert sand, but similar or higher than the Moon or
Mars.
http://en.wikipedia.org/wiki/Albedo
> When you say that this results in lower entropy, which entropy are you
> speaking of:? Earth surface entropy or exporting entropy to space?
marc.t...@wanadoo.fr
Jun 15, 2012, 10:41:29 AM6/15/12
to
On Jun 15, 3:28 pm, Richard Norman <r_s_nor...@comcast.net> wrote:
> What the paper actually claims is "Adding life to physical systems
> certainly increases entropy production. A pond full of plankton or a
> patch of grass absorbs more of the Sun s energy, and so produces more
> entropy, than a sterile pool or bare rock."
Until that point we fully agree.
> What the paper actually claims is "Adding life to physical systems
> certainly increases entropy production. A pond full of plankton or a
> patch of grass absorbs more of the Sun s energy, and so produces more
> entropy, than a sterile pool or bare rock."
> I claim that a patch of
> black basalt absorbs more of the Sun's energy than a patch of grass.
> The real difference is that a pond full of plankton or a patch of
> grass convert the energy of sunlight into heat in a far more indrect
> way than does a sterile pool or bare rock. But thermodynamics in this
> application considers the end points of a process, not the pathway to
> reach the end point. In both the living and the non-living cases,
> virtually all the absorbed energy is ultimately converted into heat.
> The amount of energy used in a living ecosystem in virtual steady
> state to produce "structure" or "order" or diversity is trivial. So
> the entropy change is the energy absorbed divided by the temperature
> of the final heat. The energy absorbed from the sun by the biosphere
> is photosynthesis: at most 8% of the incident radiation. All the rest
> of the light falling on grass or pond that is not reflected goes
> directly to heat, just as it does on the sterile pool or rock. The
> temperature of grass or pond might be lower than that of a sterile
> pool or rock but perhaps by 10 or even 15 degrees C, that is just 5%
> lower. So do the math: there is no way that it works.
given closed physical system an increase of entropy means that the
disorder of the whole system increases.
In your example it is not possible to isolate the patch of grass
(respectively the patch of black basalt) from its surroundings in the
calculation for the entropy change: the whole system for which the
entropy increases is composed of both. I don't understand how you can
easily calculate the entropy changes in the two compared situations.
> If you disagree, I would like to see the numbers, not just statements
> of "complexity" or "increased structure and diversity".
> You might argue that the world is not made of dark basalt but rather
> of lighter silicon dioxide or granites. In that case my question is
> why didn't "physical evolution" produce a dark basaltic world rather
> than a rather lighter colored biosphere because that would produce an
>
> - Show quoted text -
marc.t...@wanadoo.fr
Jun 15, 2012, 11:01:36 AM6/15/12
to
On Jun 15, 4:25 pm, Vend <ven...@virgilio.it> wrote:
> That is what I was thinking of. Of course, the Earth also radiates
> sunlight reflectively, depending on the albedo of it's surface and
> atmosphere. I don't know whether life contributes positively or
> negatively to the Earth albedo.
>
> The Earth albedo is higher than the albedo of the Moon or Mars,
> largely due to the presence of clouds, snow and large ice caps.
> According to Wikipedia the albedo of forests, grasslands and bare soil
> is lower than desert sand, but similar or higher than the Moon or
> Mars.
>
> http://en.wikipedia.org/wiki/Albedo
>
> > When you say that this results in lower entropy, which entropy are you
> > speaking of:? Earth surface entropy or exporting entropy to space?
>
> Exporting entropy to space.
Regarding the energy balance the difference I see between out present
> That is what I was thinking of. Of course, the Earth also radiates
> sunlight reflectively, depending on the albedo of it's surface and
> atmosphere. I don't know whether life contributes positively or
> negatively to the Earth albedo.
>
> The Earth albedo is higher than the albedo of the Moon or Mars,
> largely due to the presence of clouds, snow and large ice caps.
> According to Wikipedia the albedo of forests, grasslands and bare soil
> is lower than desert sand, but similar or higher than the Moon or
> Mars.
>
> http://en.wikipedia.org/wiki/Albedo
>
> > When you say that this results in lower entropy, which entropy are you
> > speaking of:? Earth surface entropy or exporting entropy to space?
>
> Exporting entropy to space.
Earth with all its organisms and an "Earth without" is that the latter
would retain a lower amount of energy because a certain amount of
energy is used by the present Earth organisms for their growth and
their reproduction. Then there would be more exporting energy to the
space (i.e., lost energy) in the case of an "Earth without".
I don't understand the kind of relation you make between the exporting
energy to space and the exporting entropy to space: can you clarify
your point?
Ernest Major
Jun 15, 2012, 11:02:22 AM6/15/12
to
In message
<79555a3b-5fe7-450a...@l5g2000vbo.googlegroups.com>,
marc.t...@wanadoo.fr writes
The amount of entropy bound up in living organisms is more or less
constant - a patch of grass may vary seasonally, but it's much the same
from year to year. So the entropy production process can be reduced to
low entropy high frequency light being absorbed at the earth's surface,
and high entropy low frequency light being emitted from the earth's
surface.
There are two competing effects here
1) albedo - all things being equal a lower albedo surface absorbs more
energy, and therefore results in a greater entropy production.
2) temperature - all things being equal a lower temperature surface
radiates lower frequency light, and there a greater entropy production.
significantly reduced atmospheric CO2 levels, lowering surface
temperature, and presumably increasing entropy production. If nature
maximises entropy production, why didn't an equivalent event occur
earlier? Alternatively, if the increased albedo reduced entropy
production, why did the event occur at all?
alias Ernest Major
<79555a3b-5fe7-450a...@l5g2000vbo.googlegroups.com>,
marc.t...@wanadoo.fr writes
constant - a patch of grass may vary seasonally, but it's much the same
from year to year. So the entropy production process can be reduced to
low entropy high frequency light being absorbed at the earth's surface,
and high entropy low frequency light being emitted from the earth's
surface.
There are two competing effects here
1) albedo - all things being equal a lower albedo surface absorbs more
energy, and therefore results in a greater entropy production.
2) temperature - all things being equal a lower temperature surface
radiates lower frequency light, and there a greater entropy production.
>
>> If you disagree, I would like to see the numbers, not just statements
>> of "complexity" or "increased structure and diversity".
>> You might argue that the world is not made of dark basalt but rather
>> of lighter silicon dioxide or granites. In that case my question is
>> why didn't "physical evolution" produce a dark basaltic world rather
>> than a rather lighter colored biosphere because that would produce an
>> even greater entropy production: the living world is not maximum.-
>>Hide quoted text -
A related question - the Azolla events of the middle Eocene
>> If you disagree, I would like to see the numbers, not just statements
>> of "complexity" or "increased structure and diversity".
>> You might argue that the world is not made of dark basalt but rather
>> of lighter silicon dioxide or granites. In that case my question is
>> why didn't "physical evolution" produce a dark basaltic world rather
>> than a rather lighter colored biosphere because that would produce an
>> even greater entropy production: the living world is not maximum.-
>>Hide quoted text -
significantly reduced atmospheric CO2 levels, lowering surface
temperature, and presumably increasing entropy production. If nature
maximises entropy production, why didn't an equivalent event occur
earlier? Alternatively, if the increased albedo reduced entropy
production, why did the event occur at all?
>>
>> - Show quoted text -
>
>
--
>> - Show quoted text -
>
>
alias Ernest Major
Vend
Jun 15, 2012, 1:04:51 PM6/15/12
to
On 15 Giu, 17:01, marc.tess...@wanadoo.fr wrote:
> On Jun 15, 4:25 pm, Vend <ven...@virgilio.it> wrote:
>
>
>
>
>
>
>
> > That is what I was thinking of. Of course, the Earth also radiates
> > sunlight reflectively, depending on the albedo of it's surface and
> > atmosphere. I don't know whether life contributes positively or
> > negatively to the Earth albedo.
>
> > The Earth albedo is higher than the albedo of the Moon or Mars,
> > largely due to the presence of clouds, snow and large ice caps.
> > According to Wikipedia the albedo of forests, grasslands and bare soil
> > is lower than desert sand, but similar or higher than the Moon or
> > Mars.
>
> >http://en.wikipedia.org/wiki/Albedo
>
> > > When you say that this results in lower entropy, which entropy are you
> > > speaking of:? Earth surface entropy or exporting entropy to space?
>
> > Exporting entropy to space.
>
> Regarding the energy balance the difference I see between out present
> Earth with all its organisms and an "Earth without" is that the latter
> would retain a lower amount of energy because a certain amount of
> energy is used by the present Earth organisms for their growth and
> their reproduction. Then there would be more exporting energy to the
> space (i.e., lost energy) in the case of an "Earth without".
The energy organisms use for their processes doesn't magically
> On Jun 15, 4:25 pm, Vend <ven...@virgilio.it> wrote:
>
>
>
>
>
>
>
> > That is what I was thinking of. Of course, the Earth also radiates
> > sunlight reflectively, depending on the albedo of it's surface and
> > atmosphere. I don't know whether life contributes positively or
> > negatively to the Earth albedo.
>
> > The Earth albedo is higher than the albedo of the Moon or Mars,
> > largely due to the presence of clouds, snow and large ice caps.
> > According to Wikipedia the albedo of forests, grasslands and bare soil
> > is lower than desert sand, but similar or higher than the Moon or
> > Mars.
>
> >http://en.wikipedia.org/wiki/Albedo
>
> > > When you say that this results in lower entropy, which entropy are you
> > > speaking of:? Earth surface entropy or exporting entropy to space?
>
> > Exporting entropy to space.
>
> Regarding the energy balance the difference I see between out present
> Earth with all its organisms and an "Earth without" is that the latter
> would retain a lower amount of energy because a certain amount of
> energy is used by the present Earth organisms for their growth and
> their reproduction. Then there would be more exporting energy to the
> space (i.e., lost energy) in the case of an "Earth without".
disappear. It is eventually relased as heat. That heat is eventually
radiated to space as electromagnetic radiation. So the power (energy
flow) balance of the Earth surface is approximately the same with or
without life:
sunlight + geothermal energy = light radiated to space
You can break up the right-hand side of the equation as:
sunlight + geothermal energy = reflected sunlight + thermal radiation
> I don't understand the kind of relation you make between the exporting
> energy to space and the exporting entropy to space: can you clarify
> your point?
albedo means less entropy is being exported.
Arkalen
Jun 15, 2012, 1:18:29 PM6/15/12
to
Earth system modelling or something of the sort. IIRC it really is just
a principle - I don't think it's proven that's how things actually work.
And I always thought it made some sense in the context of life because
life breaks down so many things and generates so much heat as a normal
part of its functioning, but I can't answer any of the questions you and
Vend raise so I'm probably wrong.
Anyway, what I heard is that the principle of entropy maximisation had
been used productively in a modelling/optimization context and that this
is what made it attractive. Claims that it can explain Life On Earth are
probably overblown at this point though.
Richard Norman
Jun 15, 2012, 3:17:26 PM6/15/12
to
On Fri, 15 Jun 2012 07:41:29 -0700 (PDT), marc.t...@wanadoo.fr
wrote:
Sorry, I used the words of the original authors to isolate a patch of
grass. Let me repeat once more the words they used: " A pond full of
is false. You have done nothing arguing about "disorder" in a vague
way to change that fact.
On a different topic, the paper goals global. In that cases the earth
is in a virtual steady state, energy in equals energy out. Neglecting
for simplicity the energy released from the earth's core by
radioactive decay, the energy input from space is that fraction of
solar radiation, which has a very high effective temperature, that is
not directly reflected back into space. The energy output to space is
microwave radiation which has a very low effective temperature.
Entropy is energy per degree so taking in energy at high temperature
(low entropy) and releasing it at low temperature (higher entropy)
represents the increase.
There are two questions that need be answered: First, is the albedo
of the earth as viewed from space lower in an earth with a biosphere
than a lifeless earth? That has to do with the total energy input:
directly reflected sunlight essentiall doesn't "enter" the earth's
budget. Second, is the effective temperature of that layer in the
upper atmosphere that does emit the microwave radiation colder in an
earth with an atmosphere than in a lifeless earth? That has to do
with the amount of entropy increase when from the energy flux into and
out of the earth.
The paper does exactly that kind of analysis totally ignoring the
albedo part and concludes that life on earth produces a better entropy
generator than would a lifeless earth. Again, this is based on the
temperature of outbound radiation, not notions of "disorder" except
for the fact that heat is a measure of disorder.
As a completely separate question, the paper talks about particular
earthly processes. Of course an organism that captures and uses a
greater percentage of food that it ingests or one that locomotes more
efficiently has a fitness advantage over an organism that is less
efficient. Everybody has always known that. Expressing the
difference in terms of entropy might be a nice exercise in physics but
does not improve the biology.
Finally, as another completely separate question, the paper discusses
ecosystem "order". It is certainly true that formulas for ecosystem
diversity based on Shannon information have been useful for ecological
studies. It is also well established that diversity in ecosystems
seems to be better or "healthier". Framing that in terms of entropy
might be an interesting exercise in physics but does not improve the
biology. Saying "biological systems maximize entropy" is not
noticably better than saying "biological systems maximize fitness"
except to a physicist who somehow things "entropy" is a legitimate
topic to study whereas "fitness" is not.
That is why I originally claimed that "The paper is a confusing mix of
disparate ideas."
wrote:
grass. Let me repeat once more the words they used: " A pond full of
plankton or a patch of grass absorbs more of the Sun s energy, and so
produces more entropy, than a sterile pool or bare rock." I say that
is false. You have done nothing arguing about "disorder" in a vague
way to change that fact.
On a different topic, the paper goals global. In that cases the earth
is in a virtual steady state, energy in equals energy out. Neglecting
for simplicity the energy released from the earth's core by
radioactive decay, the energy input from space is that fraction of
solar radiation, which has a very high effective temperature, that is
not directly reflected back into space. The energy output to space is
microwave radiation which has a very low effective temperature.
Entropy is energy per degree so taking in energy at high temperature
(low entropy) and releasing it at low temperature (higher entropy)
represents the increase.
There are two questions that need be answered: First, is the albedo
of the earth as viewed from space lower in an earth with a biosphere
than a lifeless earth? That has to do with the total energy input:
directly reflected sunlight essentiall doesn't "enter" the earth's
budget. Second, is the effective temperature of that layer in the
upper atmosphere that does emit the microwave radiation colder in an
earth with an atmosphere than in a lifeless earth? That has to do
with the amount of entropy increase when from the energy flux into and
out of the earth.
The paper does exactly that kind of analysis totally ignoring the
albedo part and concludes that life on earth produces a better entropy
generator than would a lifeless earth. Again, this is based on the
temperature of outbound radiation, not notions of "disorder" except
for the fact that heat is a measure of disorder.
As a completely separate question, the paper talks about particular
earthly processes. Of course an organism that captures and uses a
greater percentage of food that it ingests or one that locomotes more
efficiently has a fitness advantage over an organism that is less
efficient. Everybody has always known that. Expressing the
difference in terms of entropy might be a nice exercise in physics but
does not improve the biology.
Finally, as another completely separate question, the paper discusses
ecosystem "order". It is certainly true that formulas for ecosystem
diversity based on Shannon information have been useful for ecological
studies. It is also well established that diversity in ecosystems
seems to be better or "healthier". Framing that in terms of entropy
might be an interesting exercise in physics but does not improve the
biology. Saying "biological systems maximize entropy" is not
noticably better than saying "biological systems maximize fitness"
except to a physicist who somehow things "entropy" is a legitimate
topic to study whereas "fitness" is not.
That is why I originally claimed that "The paper is a confusing mix of
disparate ideas."
marc.t...@wanadoo.fr
Jun 16, 2012, 5:28:13 AM6/16/12
to
On 15 juin, 21:17, Richard Norman <r_s_nor...@comcast.net> wrote:
> Sorry, I used the words of the original authors to isolate a patch of
> grass. Let me repeat once more the words they used: " A pond full of
> plankton or a patch of grass absorbs more of the Sun s energy, and so
> produces more entropy, than a sterile pool or bare rock." I say that
> is false. You have done nothing arguing about "disorder" in a vague
> way to change that fact.
Do you disagree when it is said that in the physical processes on a
> Sorry, I used the words of the original authors to isolate a patch of
> grass. Let me repeat once more the words they used: " A pond full of
> plankton or a patch of grass absorbs more of the Sun s energy, and so
> produces more entropy, than a sterile pool or bare rock." I say that
> is false. You have done nothing arguing about "disorder" in a vague
> way to change that fact.
Earth with all its organisms, where the Sun's energy is used for the
growth and reproduction of these organisms (which corresponds to a
decrease of the entropy = production of negentropy), there must be a
corresponding higher production of entropy (i.e., exporting entropy by
the organisms) than the produced negentropy in order to be in
accordance with the second law of thermodynamics while on a "Earth
without" there is no such exporting entropy production?
Richard Norman
Jun 16, 2012, 8:00:24 AM6/16/12
to
On Sat, 16 Jun 2012 02:28:13 -0700 (PDT), marc.t...@wanadoo.fr
wrote:
>On 15 juin, 21:17, Richard Norman <r_s_nor...@comcast.net> wrote:
>> Sorry, I used the words of the original authors to isolate a patch of
>> grass. Let me repeat once more the words they used: " A pond full of
>> plankton or a patch of grass absorbs more of the Sun s energy, and so
>> produces more entropy, than a sterile pool or bare rock." I say that
>> is false. You have done nothing arguing about "disorder" in a vague
>> way to change that fact.
>Do you disagree when it is said that in the physical processes on a
>Earth with all its organisms, where the Sun's energy is used for the
>growth and reproduction of these organisms (which corresponds to a
>decrease of the entropy = production of negentropy), there must be a
>corresponding higher production of entropy (i.e., exporting entropy by
>the organisms) than the produced negentropy in order to be in
>accordance with the second law of thermodynamics while on a "Earth
>without" there is no such exporting entropy production?
<snip material clearly labelled as on different topics>
In an earlier thread I said "If you disagree, I would like to see the
the numbers.
First, in my analyses I have repeated stressed that biological systems
are in a quasi steady state. That is, the total biomass in quite the
same or in essential equivalent form is present from moment to moment,
from year to year. The argument presented is in terms of energy flow:
the principle discussed involves maximizing the _rate_ of entropy
production. The amount of energy flux that is diverted in living
systems to produce order or structure (new biomass) or, if you will,
negentropy and that is not at the same time lost as biomass dies and
is eaten or decays or otherwise loses its order and structure (and
negentropy) is quite trivial. This negentropy is very important over
the long term; it is, as you correctly point out, what drives
evolution. But it is an extremely tiny fraction of the energy flow
through the ecosystem.
So the amount of negentropy that accumulates in the biosphere is a
tiny fraction of the total energy flow through the biosystem. And the
energy flow through the biosphere is a tiny fraction of the total
energy flow through the total earth, counting biological activity and
physical processes (hydologic cycle, water and air currents, weather
patterns) all driven by solar energy. If the "goal" is to maximize
entropy production, then the minuscule increase in energy associated
with the phenomenon of "life" could easily be replaced by slight
tweaks in the way that energy flows through the non-living processes
on earth. To say that biological evolution is a consequence of some
entropy maximization phenomenon fails to understand that entropy could
be increased far greater by other relatively "simple" physical
changes: simple changes to the color of rock, for example.
So I repeat: if you want to accept the argument presented in the paper
that deals with maximum entropy production, show me the numbers about
entropy production. So your job, or more properly the real job of the
proponents of this idea, is to show that the entropy production
produced biologically is a significant fraction of the total entropy
production by all sorts of non-living physical processes.
wrote:
>On 15 juin, 21:17, Richard Norman <r_s_nor...@comcast.net> wrote:
>> Sorry, I used the words of the original authors to isolate a patch of
>> grass. Let me repeat once more the words they used: " A pond full of
>> plankton or a patch of grass absorbs more of the Sun s energy, and so
>> produces more entropy, than a sterile pool or bare rock." I say that
>> is false. You have done nothing arguing about "disorder" in a vague
>> way to change that fact.
>Do you disagree when it is said that in the physical processes on a
>Earth with all its organisms, where the Sun's energy is used for the
>growth and reproduction of these organisms (which corresponds to a
>decrease of the entropy = production of negentropy), there must be a
>corresponding higher production of entropy (i.e., exporting entropy by
>the organisms) than the produced negentropy in order to be in
>accordance with the second law of thermodynamics while on a "Earth
>without" there is no such exporting entropy production?
In an earlier thread I said "If you disagree, I would like to see the
numbers, not just statements of 'complexity' or 'increased structure
and diversity'". The term 'negentropy' is quite equivalent. Show me
the numbers.
First, in my analyses I have repeated stressed that biological systems
are in a quasi steady state. That is, the total biomass in quite the
same or in essential equivalent form is present from moment to moment,
from year to year. The argument presented is in terms of energy flow:
the principle discussed involves maximizing the _rate_ of entropy
production. The amount of energy flux that is diverted in living
systems to produce order or structure (new biomass) or, if you will,
negentropy and that is not at the same time lost as biomass dies and
is eaten or decays or otherwise loses its order and structure (and
negentropy) is quite trivial. This negentropy is very important over
the long term; it is, as you correctly point out, what drives
evolution. But it is an extremely tiny fraction of the energy flow
through the ecosystem.
So the amount of negentropy that accumulates in the biosphere is a
tiny fraction of the total energy flow through the biosystem. And the
energy flow through the biosphere is a tiny fraction of the total
energy flow through the total earth, counting biological activity and
physical processes (hydologic cycle, water and air currents, weather
patterns) all driven by solar energy. If the "goal" is to maximize
entropy production, then the minuscule increase in energy associated
with the phenomenon of "life" could easily be replaced by slight
tweaks in the way that energy flows through the non-living processes
on earth. To say that biological evolution is a consequence of some
entropy maximization phenomenon fails to understand that entropy could
be increased far greater by other relatively "simple" physical
changes: simple changes to the color of rock, for example.
So I repeat: if you want to accept the argument presented in the paper
that deals with maximum entropy production, show me the numbers about
entropy production. So your job, or more properly the real job of the
proponents of this idea, is to show that the entropy production
produced biologically is a significant fraction of the total entropy
production by all sorts of non-living physical processes.
marc.t...@wanadoo.fr
Jun 16, 2012, 8:48:20 AM6/16/12
to
On 16 juin, 14:00, Richard Norman <r_s_nor...@comcast.net> wrote:
> On Sat, 16 Jun 2012 02:28:13 -0700 (PDT), marc.tess...@wanadoo.fr
I think the question is to explain the mechanism of selection between
several possible states of a population of open, nonequilibrium
systems.
The classical explanation is fitness. Roderick Dewar's explanation is
that the state which is finally selected is "the one that can be
realized in more ways than any other". It would be only a "question of
probability".
> On Sat, 16 Jun 2012 02:28:13 -0700 (PDT), marc.tess...@wanadoo.fr
several possible states of a population of open, nonequilibrium
systems.
The classical explanation is fitness. Roderick Dewar's explanation is
that the state which is finally selected is "the one that can be
realized in more ways than any other". It would be only a "question of
probability".
Richard Norman
Jun 16, 2012, 9:39:46 AM6/16/12
to
On Sat, 16 Jun 2012 05:48:20 -0700 (PDT), marc.t...@wanadoo.fr
wrote:
What you think the question is doesn't relate to the article under
discussion. I complained about a specific statement: " A pond full
don't address that issue. The article attributes biological evolution
to a maximal entropy production principle. You don't address that
issue. Now you raise some other sort of thing putting together a
bunch of words that don't really seem to say anything.
Once again: show me the numbers. You demonstrate to me that the
evolution of life produces a state "that can be realized in more ways
than any other". Show me the evidence. Show me some proof. Otherwise
you are just spouting idle and meaningless words.
You argue that "life" is a meaningless notion, undefinable. I claim
that "question of probability", a phrase you cite, is a meaningless
notion, undefinable. Show me otherwise. I mean good hard solid
logical argument, not more arm waving verbiage.
wrote:
discussion. I complained about a specific statement: " A pond full
of plankton or a patch of grass absorbs more of the Sun s energy, and
so produces more entropy, than a sterile pool or bare rock." You
don't address that issue. The article attributes biological evolution
to a maximal entropy production principle. You don't address that
issue. Now you raise some other sort of thing putting together a
bunch of words that don't really seem to say anything.
Once again: show me the numbers. You demonstrate to me that the
evolution of life produces a state "that can be realized in more ways
than any other". Show me the evidence. Show me some proof. Otherwise
you are just spouting idle and meaningless words.
You argue that "life" is a meaningless notion, undefinable. I claim
that "question of probability", a phrase you cite, is a meaningless
notion, undefinable. Show me otherwise. I mean good hard solid
logical argument, not more arm waving verbiage.
Paul J Gans
Jun 16, 2012, 12:06:37 PM6/16/12
to
point to make.
The "driving force" in a system depends on the constraints on that
system. Entropy is overstressed by most folks. It has nothing to
do with most of this.
If you take the temperature and pressure of the steady state system
as essentially constant, the driving force is the Gibbs free energy.
One can argue that that's just the entropy in another guise, and
there is some truth to it. But it is easier to deal with.
Another point: using thermodynamic arguments in non-equilibrium
situations is fraught with difficulty. The literature is filled
with warring papers on the subject, each insisting that it can
be done and each doing it in a different way.
That's usually a sign saying "BEWARE!"
--
--- Paul J. Gans
Richard Norman
Jun 16, 2012, 1:24:48 PM6/16/12
to
not pedantic nits. However the article that generated this entire
discussion uses "maximum entropy production" specifically in
non-equilibrium conditions as the "driving force" for evolution. So
that is necessarily the subject matter.
Example: "orderly, self-organized systems are like engines
designed to level out energy gradients—while they persist,
they produce more entropy, more quickly, than a disordered
mishmash of molecules."
Or: "under the conditions on early Earth, life was the best way to
release the build-up of geothermal energy and an inevitable
consequence of that energy. Once biochemistry had got
going, subsequent chemical and Darwinian selection would
each favor the systems best at dissipating Earth’s pent-up
energy, whether geothermal or, following the invention of
photosynthesis, solar."
The entire article is a sign saying "BEWARE!"
The total global net primary productivity, the amount of energy
converted by photosynthesis into biomass and hence the total amount of
energy to support all life on earth (except for the tiny extra from
chemosynthesis) amounts to less than 0.1 % of the energy that strikes
our planet (hits the upper atmosphere). So "the systems best at
dissipating Earth's energy" manage just a tiny bit of it and
non-biological processes manage to handle one thousand times more.
That is a very tiny tail wagging an enormous dog.
Richard Norman
Jun 16, 2012, 2:05:37 PM6/16/12
to
>The "driving force" in a system depends on the constraints on that
>system. Entropy is overstressed by most folks. It has nothing to
>do with most of this.
>
>If you take the temperature and pressure of the steady state system
>as essentially constant, the driving force is the Gibbs free energy.
>One can argue that that's just the entropy in another guise, and
>there is some truth to it. But it is easier to deal with.
I once gave a colloquium in a department of "Natural Sciences" that
>system. Entropy is overstressed by most folks. It has nothing to
>do with most of this.
>
>If you take the temperature and pressure of the steady state system
>as essentially constant, the driving force is the Gibbs free energy.
>One can argue that that's just the entropy in another guise, and
>there is some truth to it. But it is easier to deal with.
included biology, chemistry, physics, and geology. To help provide
some background to this diverse group I felt compelled to include some
trivial stuff, stuff from day 1 of my physiology class, that I would
expect every scientist to know. Specifically I wrote out
delta G = delta H - T delta S
and said that, since hardly any biological process involves any
significant heat, H, that a decrease in free energy, G, was equivalent
to an increase in entropy, S.
There was an audible gasp from the physicists. "Aha, so THAT'S why
biologists never talk about entropy!"
Paul J Gans
Jun 16, 2012, 8:06:07 PM6/16/12
to
that evolution can be explained by entropy production or whatever.
As you point out the major entropy production has nothing to do
with life.
For me imperfect reproduction with differential survival rates is
sufficient to explain evolution. My personal view is that given
the chemical facts involved evolution is inevitable.
And one can leave thermodynamics out of it.
marc.t...@wanadoo.fr
Jun 17, 2012, 4:08:39 AM6/17/12
to
On 17 juin, 02:06, Paul J Gans <gan...@panix.com> wrote:
> >>>On Sat, 16 Jun 2012 02:28:13 -0700 (PDT), marc.tess...@wanadoo.fr
So you both probably disagree with that paragraph:
"One hundred years ago, one of the hottest debates in biology
concerned vitalism—whether living things were made from the same
chemicals as inanimate matter, and whether they were animated by a
“vital force” unique to biological systems, or obeyed the same laws of
physics as dead matter.
A century on, we know that living things and dead things are made from
the same stuff, and subject to the same forces.
Perhaps in another hundred years, no one will think that we need one
set of theories for biology and another for physics".
> Richard Norman <r_s_nor...@comcast.net> wrote:
> >On Sat, 16 Jun 2012 16:06:37 +0000 (UTC), Paul J Gans
> ><gan...@panix.com> wrote:
> >>Richard Norman <r_s_nor...@comcast.net> wrote:
> >On Sat, 16 Jun 2012 16:06:37 +0000 (UTC), Paul J Gans
> ><gan...@panix.com> wrote:
> >>>On Sat, 16 Jun 2012 02:28:13 -0700 (PDT), marc.tess...@wanadoo.fr
"One hundred years ago, one of the hottest debates in biology
concerned vitalism—whether living things were made from the same
chemicals as inanimate matter, and whether they were animated by a
“vital force” unique to biological systems, or obeyed the same laws of
physics as dead matter.
A century on, we know that living things and dead things are made from
the same stuff, and subject to the same forces.
Perhaps in another hundred years, no one will think that we need one
set of theories for biology and another for physics".
Vend
Jun 17, 2012, 8:36:15 AM6/17/12
to
doman-specific theories, AFAIK.
Richard Norman
Jun 17, 2012, 10:09:25 AM6/17/12
to
On Sun, 17 Jun 2012 01:08:39 -0700 (PDT), marc.t...@wanadoo.fr
wrote:
There are statements in the article that are valid, even though the
ones I quoted which I think represent the main thrust are not.
It is quite obvious that the mechanisms of biology, of "life" as i
insist on phrasing it, are physical. Entropy applies to living things
just as it does to everything else in the universe. What Paul said,
and I fully agree, is that entropy is not a useful tool to use in
describing many aspects of biology including evolution. The reason
rivers run downhill is because entropy increases. That does not give
us a useful tool in dealing with hydrodynamics. Paul referred to
Gibbs free energy as a very useful concept in biochemistry and
biophysics. As I indicated in a different post, it is really entropy
in a different guise, but in a far more useful one. As Paul very
correctly pointed out: " My particular prejudice is against notions
that evolution can be explained by entropy production." That is very
different from saying that evolution has nothing to do with entropy.
Biology operates on a very different level from physics. Although the
beating of the heart depends totally on quantum electrodynamics plus
general relativity, applying quantum electrodynamics plus general
relativity to cardiovascular dynamics is quite worthless. This
notwithstanding the fact that quantum physics underlies the chemical
bonds holding together the molecules that make of the cardiovascular
system. Everything in its place. Biology has its own place.
wrote:
ones I quoted which I think represent the main thrust are not.
It is quite obvious that the mechanisms of biology, of "life" as i
insist on phrasing it, are physical. Entropy applies to living things
just as it does to everything else in the universe. What Paul said,
and I fully agree, is that entropy is not a useful tool to use in
describing many aspects of biology including evolution. The reason
rivers run downhill is because entropy increases. That does not give
us a useful tool in dealing with hydrodynamics. Paul referred to
Gibbs free energy as a very useful concept in biochemistry and
biophysics. As I indicated in a different post, it is really entropy
in a different guise, but in a far more useful one. As Paul very
correctly pointed out: " My particular prejudice is against notions
that evolution can be explained by entropy production." That is very
different from saying that evolution has nothing to do with entropy.
Biology operates on a very different level from physics. Although the
beating of the heart depends totally on quantum electrodynamics plus
general relativity, applying quantum electrodynamics plus general
relativity to cardiovascular dynamics is quite worthless. This
notwithstanding the fact that quantum physics underlies the chemical
bonds holding together the molecules that make of the cardiovascular
system. Everything in its place. Biology has its own place.
marc.t...@wanadoo.fr
Jun 17, 2012, 5:14:58 PM6/17/12
to
On 17 juin, 16:09, Richard Norman <r_s_nor...@comcast.net> wrote:
> On Sun, 17 Jun 2012 01:08:39 -0700 (PDT), marc.tess...@wanadoo.fr
Do you mean that the driving force for a river to run downhill is the
second law of thermodynamics? Isn't the gravitation? Can you clarify
your view?
> Paul referred to
> Gibbs free energy as a very useful concept in biochemistry and
> biophysics. As I indicated in a different post, it is really entropy
> in a different guise, but in a far more useful one. As Paul very
> correctly pointed out: " My particular prejudice is against notions
> that evolution can be explained by entropy production." That is very
> different from saying that evolution has nothing to do with entropy.
>
> Biology operates on a very different level from physics. Although the
> beating of the heart depends totally on quantum electrodynamics plus
> general relativity, applying quantum electrodynamics plus general
> relativity to cardiovascular dynamics is quite worthless. This
> notwithstanding the fact that quantum physics underlies the chemical
> bonds holding together the molecules that make of the cardiovascular
> system.
Well don't you think that there are also fluid mechanics, elasticity
laws and other physical laws which are very useful in the
understanding of blood pressure and cardiovascular disorders?
> Everything in its place. Biology has its own place.
Biology means "the science of life". This is indeed the issue ... for
me!
> On Sun, 17 Jun 2012 01:08:39 -0700 (PDT), marc.tess...@wanadoo.fr
second law of thermodynamics? Isn't the gravitation? Can you clarify
your view?
> Paul referred to
> Gibbs free energy as a very useful concept in biochemistry and
> biophysics. As I indicated in a different post, it is really entropy
> in a different guise, but in a far more useful one. As Paul very
> correctly pointed out: " My particular prejudice is against notions
> that evolution can be explained by entropy production." That is very
> different from saying that evolution has nothing to do with entropy.
>
> Biology operates on a very different level from physics. Although the
> beating of the heart depends totally on quantum electrodynamics plus
> general relativity, applying quantum electrodynamics plus general
> relativity to cardiovascular dynamics is quite worthless. This
> notwithstanding the fact that quantum physics underlies the chemical
> bonds holding together the molecules that make of the cardiovascular
> system.
laws and other physical laws which are very useful in the
understanding of blood pressure and cardiovascular disorders?
> Everything in its place. Biology has its own place.
me!
Richard Norman
Jun 17, 2012, 5:36:32 PM6/17/12
to
On Sun, 17 Jun 2012 14:14:58 -0700 (PDT), marc.t...@wanadoo.fr
wrote:
You totally misunderstand the issue.
First, yes gravity is the reason why water runs downhill. But unless
you want to get into arcane general relativity, according to classical
physics the energy in the gravitational field released by water
running downhill is converted to kinetic energy of the water moving
which is then dissipated by viscous and frictional forces within the
stream and between the stream and the riverbed. In the end,
gravitational energy is converted to heat at the ambient temperature
which is an increase in entropy. A river really does move downhill
because that is how it increases entropy. But looking at the entropy
in no way helps us understand or explain the phenomenon. I do not
wish to discuss rivers in terms of general relativity -- that is far
outside my comfort zone.
Second, certainly Poiseuille's law and Laplace's law and Bernoulli's
law and Hook's law and all sorts of physics is involved in the
cardiovascular system. I taught that stuff for many decades making
full use of the biophysics of systems as well as the biochemistry of
cells. However you again miss the point. The laws that you describe
are all merely applications of quantum electrodynamics and general
relativity. However it makes no sense to talk about cardiovascular
dynamics in terms of the fundamental physics but rather only in terms
of highly derived principles, phenomenological principles in fact.
That is exactly the same as Paul saying thate Gibbs free energy is
useful for most biochemistry and biophysics whereas entropy is not.
Biology operates on a very different level from physics. Biophysics
does apply to cells and tissues and organ systems. However it becomes
less useful in understanding ecosystem development or macroevolution
even though many separate aspects of ecosystem function or
macroevolution might rely on biophysical principles.
wrote:
First, yes gravity is the reason why water runs downhill. But unless
you want to get into arcane general relativity, according to classical
physics the energy in the gravitational field released by water
running downhill is converted to kinetic energy of the water moving
which is then dissipated by viscous and frictional forces within the
stream and between the stream and the riverbed. In the end,
gravitational energy is converted to heat at the ambient temperature
which is an increase in entropy. A river really does move downhill
because that is how it increases entropy. But looking at the entropy
in no way helps us understand or explain the phenomenon. I do not
wish to discuss rivers in terms of general relativity -- that is far
outside my comfort zone.
Second, certainly Poiseuille's law and Laplace's law and Bernoulli's
law and Hook's law and all sorts of physics is involved in the
cardiovascular system. I taught that stuff for many decades making
full use of the biophysics of systems as well as the biochemistry of
cells. However you again miss the point. The laws that you describe
are all merely applications of quantum electrodynamics and general
relativity. However it makes no sense to talk about cardiovascular
dynamics in terms of the fundamental physics but rather only in terms
of highly derived principles, phenomenological principles in fact.
That is exactly the same as Paul saying thate Gibbs free energy is
useful for most biochemistry and biophysics whereas entropy is not.
Biology operates on a very different level from physics. Biophysics
does apply to cells and tissues and organ systems. However it becomes
less useful in understanding ecosystem development or macroevolution
even though many separate aspects of ecosystem function or
macroevolution might rely on biophysical principles.
Richard Norman
Jun 17, 2012, 6:38:45 PM6/17/12
to
On Sat, 16 Jun 2012 02:28:13 -0700 (PDT), marc.t...@wanadoo.fr
wrote:
<snip to retain a single point>
>Do you disagree when it is said that in the physical processes on a
>Earth with all its organisms, where the Sun's energy is used for the
>growth and reproduction of these organisms (which corresponds to a
>decrease of the entropy = production of negentropy), there must be a
>corresponding higher production of entropy (i.e., exporting entropy by
>the organisms) than the produced negentropy in order to be in
>accordance with the second law of thermodynamics while on a "Earth
>without" there is no such exporting entropy production?
I believe you have a fundamental error in assumptions and arguments
here. Let us say that there is a reality to the concept of biological
"negentropy", corresponding to the structure and organization or
biological cells and tissues and organs and organisms and ecosystems,
not to mention the "information content" of all the genomes involved.
Then all that is derived from the energy flux in the metabolism of all
the organisms (I would prefer to say "living" things) involved. The
open system argument about life obeying the 2nd law is that the
increase in entropy in the remainder of the system compensates for
this decrease in entropy (negentropy). The problem is _when_.
The sun radiates as it does whether or not there are living things
capturing sunlight for photosynthesis. In the absence of
photosynthesis, the energy of sunlight is converted to heat, an
increase in entropy here on earth. In the presence of photosynthesis,
a tiny fraction of the energy of sunlight is converted into the energy
content of structured biomass with the rest going into heat. So there
is less entropy being generated here on earth. Nothing changes
anywhere in the rest of the universe so that the presence of life
DEcreases entropy production, not INcreases it.
But living things die, and decompose or get eaten. Eventually, the
carbohydrates and secondarily the proteins produced from
photosynthesis get metabolized releasing heat. Some fraction goes
into mechanical energy as organisms move around but this, too, gets
dissipated as heat. So eventually the entropy catches up. Once the
biosphere reaches a steady state in biomass, then metabolic
destruction (respiration) belances metabolic construction (anabolic
photosynthesis) so that all the sun's energy capture in photosynthesis
is released as heat, so entropy is produced at exactly the same rate
with or without life (assuming the ambient temperature at which the
final heat is expressed is the same).
The processes of life and the production of negentropy do NOT increase
the production of entropy elsewhere. They just DELAY the production
of entropy until the structured biosystem disintegrates and decays
completely, as it eventually must.
In other words, the principle of maximazation of entropy totally fails
if it is applied in this way.
Note to Paul: I am using the entropy argument loosely, but adhering
to the way argument was formulated. You can argue on your own that
the whole approach, including the concept of "negentropy" is flawed.
wrote:
<snip to retain a single point>
>Do you disagree when it is said that in the physical processes on a
>Earth with all its organisms, where the Sun's energy is used for the
>growth and reproduction of these organisms (which corresponds to a
>decrease of the entropy = production of negentropy), there must be a
>corresponding higher production of entropy (i.e., exporting entropy by
>the organisms) than the produced negentropy in order to be in
>accordance with the second law of thermodynamics while on a "Earth
>without" there is no such exporting entropy production?
here. Let us say that there is a reality to the concept of biological
"negentropy", corresponding to the structure and organization or
biological cells and tissues and organs and organisms and ecosystems,
not to mention the "information content" of all the genomes involved.
Then all that is derived from the energy flux in the metabolism of all
the organisms (I would prefer to say "living" things) involved. The
open system argument about life obeying the 2nd law is that the
increase in entropy in the remainder of the system compensates for
this decrease in entropy (negentropy). The problem is _when_.
The sun radiates as it does whether or not there are living things
capturing sunlight for photosynthesis. In the absence of
photosynthesis, the energy of sunlight is converted to heat, an
increase in entropy here on earth. In the presence of photosynthesis,
a tiny fraction of the energy of sunlight is converted into the energy
content of structured biomass with the rest going into heat. So there
is less entropy being generated here on earth. Nothing changes
anywhere in the rest of the universe so that the presence of life
DEcreases entropy production, not INcreases it.
But living things die, and decompose or get eaten. Eventually, the
carbohydrates and secondarily the proteins produced from
photosynthesis get metabolized releasing heat. Some fraction goes
into mechanical energy as organisms move around but this, too, gets
dissipated as heat. So eventually the entropy catches up. Once the
biosphere reaches a steady state in biomass, then metabolic
destruction (respiration) belances metabolic construction (anabolic
photosynthesis) so that all the sun's energy capture in photosynthesis
is released as heat, so entropy is produced at exactly the same rate
with or without life (assuming the ambient temperature at which the
final heat is expressed is the same).
The processes of life and the production of negentropy do NOT increase
the production of entropy elsewhere. They just DELAY the production
of entropy until the structured biosystem disintegrates and decays
completely, as it eventually must.
In other words, the principle of maximazation of entropy totally fails
if it is applied in this way.
Note to Paul: I am using the entropy argument loosely, but adhering
to the way argument was formulated. You can argue on your own that
the whole approach, including the concept of "negentropy" is flawed.
Vend
Jun 18, 2012, 5:32:32 AM6/18/12
to
On 15 Giu, 19:18, Arkalen <arka...@inbox.com> wrote:
> Anyway, what I heard is that the principle of entropy maximisation had
> been used productively in a modelling/optimization context and that this
> is what made it attractive. Claims that it can explain Life On Earth are
> probably overblown at this point though.
Can you suggest some tutorials on non-equilibrium thermodynamics? I'm
> Anyway, what I heard is that the principle of entropy maximisation had
> been used productively in a modelling/optimization context and that this
> is what made it attractive. Claims that it can explain Life On Earth are
> probably overblown at this point though.
not a physicist, but I've some familiarity with equilibrium
thermodynamics.
marc.t...@wanadoo.fr
Jun 18, 2012, 6:31:20 AM6/18/12
to
On 17 juin, 23:36, Richard Norman <r_s_nor...@comcast.net> wrote:
> First, yes gravity is the reason why water runs downhill. But unless
> you want to get into arcane general relativity, according to classical
> physics the energy in the gravitational field released by water
> running downhill is converted to kinetic energy of the water moving
> which is then dissipated by viscous and frictional forces within the
> stream and between the stream and the riverbed. In the end,
> gravitational energy is converted to heat at the ambient temperature
> which is an increase in entropy. A river really does move downhill
> because that is how it increases entropy.
Now I quite understand you point and I fully agree with you.
> First, yes gravity is the reason why water runs downhill. But unless
> you want to get into arcane general relativity, according to classical
> physics the energy in the gravitational field released by water
> running downhill is converted to kinetic energy of the water moving
> which is then dissipated by viscous and frictional forces within the
> stream and between the stream and the riverbed. In the end,
> gravitational energy is converted to heat at the ambient temperature
> which is an increase in entropy. A river really does move downhill
> because that is how it increases entropy.
Why wouldn't be possible to apply the same reasoning to the evolution
mechanisms?
> But looking at the entropy
> in no way helps us understand or explain the phenomenon. I do not
> wish to discuss rivers in terms of general relativity -- that is far
> outside my comfort zone.
>
> Second, certainly Poiseuille's law and Laplace's law and Bernoulli's
> law and Hook's law and all sorts of physics is involved in the
> cardiovascular system. I taught that stuff for many decades making
> full use of the biophysics of systems as well as the biochemistry of
> cells. However you again miss the point. The laws that you describe
> are all merely applications of quantum electrodynamics and general
> relativity. However it makes no sense to talk about cardiovascular
> dynamics in terms of the fundamental physics but rather only in terms
> of highly derived principles, phenomenological principles in fact.
> That is exactly the same as Paul saying thate Gibbs free energy is
> useful for most biochemistry and biophysics whereas entropy is not.
understanding of the processes involved in open dissipative far-from-
equilibrium systems like the extant organisms as we know them.
> Biology operates on a very different level from physics. Biophysics
> does apply to cells and tissues and organ systems. However it becomes
> less useful in understanding ecosystem development or macroevolution
> even though many separate aspects of ecosystem function or
> macroevolution might rely on biophysical principles.
Richard Norman
Jun 18, 2012, 7:27:22 AM6/18/12
to
On Mon, 18 Jun 2012 03:31:20 -0700 (PDT), marc.t...@wanadoo.fr
wrote:
Questions, questions. Never answers or definitive material or
rebuttals of my arguments.
Entropy is simply not a fruitful way of approaching most problems even
though it may be involved ultimately. Quantum mechanics is not a
fruitful way of solving almost any problem outside the world of the
atomic or microscopic even though quantum mechanics may form the basis
for what we see in our macroscopic world.
By the way, now that you have stopped snipping everything you see,
another improvement in your posting style would be to separate your
comments by a blank line from what you are answering. I have added
those lines above. Formatting this way helps the reader easily see
what is happening. That is exactly why paragraphs are separated by
blank lines.
wrote:
rebuttals of my arguments.
Entropy is simply not a fruitful way of approaching most problems even
though it may be involved ultimately. Quantum mechanics is not a
fruitful way of solving almost any problem outside the world of the
atomic or microscopic even though quantum mechanics may form the basis
for what we see in our macroscopic world.
By the way, now that you have stopped snipping everything you see,
another improvement in your posting style would be to separate your
comments by a blank line from what you are answering. I have added
those lines above. Formatting this way helps the reader easily see
what is happening. That is exactly why paragraphs are separated by
blank lines.
marc.t...@wanadoo.fr
Jun 18, 2012, 7:56:22 AM6/18/12
to
On 18 juin, 13:27, Richard Norman <r_s_nor...@comcast.net> wrote:
>> Questions, questions. Never answers or definitive material or
> rebuttals of my arguments.
>
> Entropy is simply not a fruitful way of approaching most problems even
> though it may be involved ultimately. Quantum mechanics is not a
> fruitful way of solving almost any problem outside the world of the
> atomic or microscopic even though quantum mechanics may form the basis
> for what we see in our macroscopic world.
>
> By the way, now that you have stopped snipping everything you see,
> another improvement in your posting style would be to separate your
> comments by a blank line from what you are answering. I have added
> those lines above. Formatting this way helps the reader easily see
> what is happening. That is exactly why paragraphs are separated by
> blank lines.
Sorry for the questions but I think it is also a good way to discuss
>> Questions, questions. Never answers or definitive material or
> rebuttals of my arguments.
>
> Entropy is simply not a fruitful way of approaching most problems even
> though it may be involved ultimately. Quantum mechanics is not a
> fruitful way of solving almost any problem outside the world of the
> atomic or microscopic even though quantum mechanics may form the basis
> for what we see in our macroscopic world.
>
> By the way, now that you have stopped snipping everything you see,
> another improvement in your posting style would be to separate your
> comments by a blank line from what you are answering. I have added
> those lines above. Formatting this way helps the reader easily see
> what is happening. That is exactly why paragraphs are separated by
> blank lines.
and to be sure that we're on the same wavelength (see the example of
the relationship between a river and entropy).
If you ask me any questions I think I won't have any displeasure to
try to answer these. The only possibility might be that I ask you to
clarify these if I don't quite understand what you ask for.
Then I would be very much interested by your response to my question:
which specific biological laws do you think of?
Richard Norman
Jun 18, 2012, 8:29:33 AM6/18/12
to
On Mon, 18 Jun 2012 04:56:22 -0700 (PDT), marc.t...@wanadoo.fr
wrote:
You propose the topic and some information about it along with your
interpretation or analysis and we can go from there. Otherwise, I get
the impression, quite possibly mistaken, that I am doing most of the
discussing.
wrote:
interpretation or analysis and we can go from there. Otherwise, I get
the impression, quite possibly mistaken, that I am doing most of the
discussing.
marc.t...@wanadoo.fr
Jun 18, 2012, 9:07:10 AM6/18/12
to
On 18 juin, 14:29, Richard Norman <r_s_nor...@comcast.net> wrote:
> On Mon, 18 Jun 2012 04:56:22 -0700 (PDT), marc.tess...@wanadoo.fr
> discussing.- Masquer le texte des messages pr�c�dents -
>
> - Afficher le texte des messages pr�c�dents -
Is there any problem if you are in the spotlight?
But you think that the balance questions/answers is not in your favor:
then, which questions do you want I answer?
> On Mon, 18 Jun 2012 04:56:22 -0700 (PDT), marc.tess...@wanadoo.fr
>
> - Afficher le texte des messages pr�c�dents -
Is there any problem if you are in the spotlight?
But you think that the balance questions/answers is not in your favor:
then, which questions do you want I answer?
marc.t...@wanadoo.fr
Jun 18, 2012, 9:53:53 AM6/18/12
to
Richard Norman
Jun 18, 2012, 10:23:24 AM6/18/12
to
On Mon, 18 Jun 2012 06:07:10 -0700 (PDT), marc.t...@wanadoo.fr
wrote:
>> discussing.- Masquer le texte des messages précédents -
>>
>> - Afficher le texte des messages précédents -
responding to my complaint about your constant questioning with only
more questions.
wrote:
>>
>> - Afficher le texte des messages précédents -
>
>Is there any problem if you are in the spotlight?
>But you think that the balance questions/answers is not in your favor:
>then, which questions do you want I answer?
You are being either very naive or trying to be very clever in
>Is there any problem if you are in the spotlight?
>But you think that the balance questions/answers is not in your favor:
>then, which questions do you want I answer?
responding to my complaint about your constant questioning with only
more questions.
marc.t...@wanadoo.fr
Jun 18, 2012, 10:58:01 AM6/18/12
to
On 18 juin, 00:38, Richard Norman <r_s_nor...@comcast.net> wrote:
> On Sat, 16 Jun 2012 02:28:13 -0700 (PDT), marc.tess...@wanadoo.fr
I recommend you to read the paper by Hoelzer et al. (2006) which I
think answers your question about the amount of sun's energy capture
in photosynthesis: I can email it to you if you like.
The authors made calculations (described in the appendix) and found
that "from simple considerations of energy and momentum conservation,
that (inelastic) light absorption transfers roughly one billion times
as much energy per event from the visible to microwave bands, as
competing elastic scattering processes, when the atoms participating
in the two processes cycle between comparable (low) temperatures. An
aggregate consequence of photosynthesis is therefore that the
effective specific heat, the energy absorbed per degree of warming, of
the earth as a whole is increased".
They add "Most abiotic conversion of visible to thermal energy on
earth occurs through diffuse, multiple scattering of light in the
oceans, made possible by the unique physical properties of water. This
is the major source of energy
driving global-scale weather and climate, but it is incapable of
generating the structures of life because of the small energy capture
per molecule and per scattering event. Photosynthesis, while smaller
in net energy capture because of the tiny mass of life compared with
the mass of the oceans, contributes a parallel channel by preserving
large fractions of the energy from visible photons in individual
molecular bonds (Blankenship, 2001). The energy and entropy flows
through this parallel channel, inaccessible to weather, provide the
source of free energy to create and maintain biochemical networks
capable of supporting photosynthesis".
And "The transduction of sunlight not only makes photosynthetic life
possible, but also it appears to have stabilized its core chemistry
even in the face of major shocks to planetary ecosystems, such as
those resulting in recurring mass extinctions. This universally known
but underemphasized fact suggests that photosynthesizing life is a
statistically favoured component of the biosphere, or that a high-flux
channel for light transduction is a favoured endpoint, towards which
perturbed ecosystems recover".
Reference:
Hoelzer GA, Smith E, Pepper JW. 2006. On the logical relationship
between natural selection and self-organization. J Evolution Biol
19:1785-1794.
> On Sat, 16 Jun 2012 02:28:13 -0700 (PDT), marc.tess...@wanadoo.fr
think answers your question about the amount of sun's energy capture
in photosynthesis: I can email it to you if you like.
The authors made calculations (described in the appendix) and found
that "from simple considerations of energy and momentum conservation,
that (inelastic) light absorption transfers roughly one billion times
as much energy per event from the visible to microwave bands, as
competing elastic scattering processes, when the atoms participating
in the two processes cycle between comparable (low) temperatures. An
aggregate consequence of photosynthesis is therefore that the
effective specific heat, the energy absorbed per degree of warming, of
the earth as a whole is increased".
They add "Most abiotic conversion of visible to thermal energy on
earth occurs through diffuse, multiple scattering of light in the
oceans, made possible by the unique physical properties of water. This
is the major source of energy
driving global-scale weather and climate, but it is incapable of
generating the structures of life because of the small energy capture
per molecule and per scattering event. Photosynthesis, while smaller
in net energy capture because of the tiny mass of life compared with
the mass of the oceans, contributes a parallel channel by preserving
large fractions of the energy from visible photons in individual
molecular bonds (Blankenship, 2001). The energy and entropy flows
through this parallel channel, inaccessible to weather, provide the
source of free energy to create and maintain biochemical networks
capable of supporting photosynthesis".
And "The transduction of sunlight not only makes photosynthetic life
possible, but also it appears to have stabilized its core chemistry
even in the face of major shocks to planetary ecosystems, such as
those resulting in recurring mass extinctions. This universally known
but underemphasized fact suggests that photosynthesizing life is a
statistically favoured component of the biosphere, or that a high-flux
channel for light transduction is a favoured endpoint, towards which
perturbed ecosystems recover".
Reference:
Hoelzer GA, Smith E, Pepper JW. 2006. On the logical relationship
between natural selection and self-organization. J Evolution Biol
19:1785-1794.
Vend
Jun 18, 2012, 6:49:25 PM6/18/12
to
equilibrium thermodynamics before venturing into its proposed
applications to biology.
Richard Norman
Jun 18, 2012, 7:23:38 PM6/18/12
to
On Mon, 18 Jun 2012 07:58:01 -0700 (PDT), marc.t...@wanadoo.fr
wrote:
Unfortunately for lurkers, I do not see that paper available free
on-line. I do have it though and will email it on request. Just
delete the two underscores in my listed email address for your
request.
Unfortunately for Marc, the paper does not really support your
argument. It does not talk about the amount of light captured in
photosynthesis in comparison to the vastly larger capture of light
energy by non-living physical systems.
It is true that for light energy to actually be harnassed, it must be
captured by inelastic processes. I do not believe the statement in
the paper that: " An aggregate consequence of photosynthesis is
not to any significant or even measurable degree. Photosynthesis
converts almost all of the incident light energy to heat, only a tiny
fraction of that is "saved" as synthesized organic compounds. Of
those organic compounds, almost all are recycled by respiration. A
truly tiny amount is preserved as biomass. However physical processes
also retain some of the sun's energy without releasing it as heat. For
example, evaporation of water in the hydrologic cycle is initiated by
the absorption of light energy. Not all the energy is converted to
heat, some goes into converting liquid water to water vapor. Other
factors use sun energy to cause winds to lift the evaporated water to
great altitude where it is deposited on mountain tops. So if the
glacial caps on mountains grow, that means that a substantial amount
of sun energy is thereby "put into storage", just as in the case when
biomass is grown but sequestered and not consumed. I would like to
see numbers to indicate that photosynthesis actually changes the heat
capacity of the entire earth. For example, consider the following
experiment. Put green leaves in the sun in an enclosed container so
that they can do photosynthesis. Measure the rate at which the
container warms from the inefficiencies of photosynthesis as light is
absorbed and turned into heat instead of "being captured." Now do
exactly the same experiment with exactly the same leaves in the same
chamber but this time in an atmosphere completely devoid of CO2 so
that no photosynthesis can occur. There are also chemical means of
blocking the reactions of photosynthesis that will do the same thing.
The leaves are just as green as before meaning they will absorb just
as much light as before. However this time ALL the energy will be
converted to heat. I am quite willing to bet that there will be
absolutely no observable difference in temperature change. The
presence of photosynthesis may conceptuall change the heat capacity of
a system but not to any measureable degree.
The section of the paper you quote goes on to describe the trully
massive energy flows in weather and climate even though they result
from an enormous number of elastic scattering and reflection events,
each of which absorbs only a tiny amount of energy. The magnitude of
energy flux through these "inefficient and useless" interactions
greatly exceed the magnitude of energy flux through the "more useful"
inelastic absorption by chlorophyll and other plant pigments. (quotes
are my own, not taken from Hoelzer). Of course there are inorganic
compounds on earth that absorb light inelastically, just like the
organic ones.
The remainder of your quotes only say what is already well known: the
energy capture by photosynthesis is what drives the entire biosphere
(except for chemosynthesis in deep sea vents). And the entire
biosphere is totally dependent on the primary producers, the green
plants. Hence, in a global mass extinction, or a local extinction
event like the explosion at Mt. St. Helens, it is the green stuff --
plants and cyanobacteria and all the diverse algae (plus some purple
photosynthesizers) -- that recovers first and forms the basis for
everything else to recover. Without photosynthesis we would have no
life. Is that what is meant by " stabilized its core chemistry" is
supposed to mean? Writing " a high-flux channel for light
transduction is a favoured endpoint" is just an overblown way of
saying "lving systems need energy and the only available source is
light radiation from the sun. Hence a channel that effectively
channels the energy of sunlight into living systems is a favored
endpoint in the evolution of life." Doh! Put that way is sure sounds
good but doesn't really add much to our understanding of things.
There is a lot of value in the paper because self organizing systems
are a truly important part of life's processes. Here I just responded
to the portion you quoted.
wrote:
on-line. I do have it though and will email it on request. Just
delete the two underscores in my listed email address for your
request.
Unfortunately for Marc, the paper does not really support your
argument. It does not talk about the amount of light captured in
photosynthesis in comparison to the vastly larger capture of light
energy by non-living physical systems.
It is true that for light energy to actually be harnassed, it must be
captured by inelastic processes. I do not believe the statement in
the paper that: " An aggregate consequence of photosynthesis is
therefore that the effective specific heat, the energy absorbed per
degree of warming, of the earth as a whole is increased". At least
not to any significant or even measurable degree. Photosynthesis
converts almost all of the incident light energy to heat, only a tiny
fraction of that is "saved" as synthesized organic compounds. Of
those organic compounds, almost all are recycled by respiration. A
truly tiny amount is preserved as biomass. However physical processes
also retain some of the sun's energy without releasing it as heat. For
example, evaporation of water in the hydrologic cycle is initiated by
the absorption of light energy. Not all the energy is converted to
heat, some goes into converting liquid water to water vapor. Other
factors use sun energy to cause winds to lift the evaporated water to
great altitude where it is deposited on mountain tops. So if the
glacial caps on mountains grow, that means that a substantial amount
of sun energy is thereby "put into storage", just as in the case when
biomass is grown but sequestered and not consumed. I would like to
see numbers to indicate that photosynthesis actually changes the heat
capacity of the entire earth. For example, consider the following
experiment. Put green leaves in the sun in an enclosed container so
that they can do photosynthesis. Measure the rate at which the
container warms from the inefficiencies of photosynthesis as light is
absorbed and turned into heat instead of "being captured." Now do
exactly the same experiment with exactly the same leaves in the same
chamber but this time in an atmosphere completely devoid of CO2 so
that no photosynthesis can occur. There are also chemical means of
blocking the reactions of photosynthesis that will do the same thing.
The leaves are just as green as before meaning they will absorb just
as much light as before. However this time ALL the energy will be
converted to heat. I am quite willing to bet that there will be
absolutely no observable difference in temperature change. The
presence of photosynthesis may conceptuall change the heat capacity of
a system but not to any measureable degree.
The section of the paper you quote goes on to describe the trully
massive energy flows in weather and climate even though they result
from an enormous number of elastic scattering and reflection events,
each of which absorbs only a tiny amount of energy. The magnitude of
energy flux through these "inefficient and useless" interactions
greatly exceed the magnitude of energy flux through the "more useful"
inelastic absorption by chlorophyll and other plant pigments. (quotes
are my own, not taken from Hoelzer). Of course there are inorganic
compounds on earth that absorb light inelastically, just like the
organic ones.
The remainder of your quotes only say what is already well known: the
energy capture by photosynthesis is what drives the entire biosphere
(except for chemosynthesis in deep sea vents). And the entire
biosphere is totally dependent on the primary producers, the green
plants. Hence, in a global mass extinction, or a local extinction
event like the explosion at Mt. St. Helens, it is the green stuff --
plants and cyanobacteria and all the diverse algae (plus some purple
photosynthesizers) -- that recovers first and forms the basis for
everything else to recover. Without photosynthesis we would have no
life. Is that what is meant by " stabilized its core chemistry" is
supposed to mean? Writing " a high-flux channel for light
transduction is a favoured endpoint" is just an overblown way of
saying "lving systems need energy and the only available source is
light radiation from the sun. Hence a channel that effectively
channels the energy of sunlight into living systems is a favored
endpoint in the evolution of life." Doh! Put that way is sure sounds
good but doesn't really add much to our understanding of things.
There is a lot of value in the paper because self organizing systems
are a truly important part of life's processes. Here I just responded
to the portion you quoted.
marc.t...@wanadoo.fr
Jun 19, 2012, 7:13:31 AM6/19/12
to
On Jun 19, 1:23 am, Richard Norman <r_s_nor...@comcast.net> wrote:
> Unfortunately for Marc, the paper does not really support your
> argument. It does not talk about the amount of light captured in
> photosynthesis in comparison to the vastly larger capture of light
> energy by non-living physical systems.
>
> It is true that for light energy to actually be harnassed, it must be
> captured by inelastic processes. I do not believe the statement in
> the paper that: " An aggregate consequence of photosynthesis is
> therefore that the effective specific heat, the energy absorbed per
> degree of warming, of the earth as a whole is increased".
Do you agree with the calculation of the authors (see Appendix)? Then
> Unfortunately for Marc, the paper does not really support your
> argument. It does not talk about the amount of light captured in
> photosynthesis in comparison to the vastly larger capture of light
> energy by non-living physical systems.
>
> It is true that for light energy to actually be harnassed, it must be
> captured by inelastic processes. I do not believe the statement in
> the paper that: " An aggregate consequence of photosynthesis is
> therefore that the effective specific heat, the energy absorbed per
> degree of warming, of the earth as a whole is increased".
that "from simple considerations of energy and momentum conservation,
(inelastic) light absorption transfers roughly one billion times as
much energy per event from the visible to microwave bands, as
competing elastic scattering processes, when the atoms participating
in the two processes cycle between comparable (low) temperatures"?
much energy per event from the visible to microwave bands, as
competing elastic scattering processes, when the atoms participating
And, as mentioned in the appendix, that "with such a large multiplier
per event, though, even a modest fraction of terrestrial matter
rendered photosynthetic by plants can produce a large enough change in
energy transport to power substantial chemical machinery?
>
> read more »- Hide quoted text -
>
> - Show quoted text -
Ernest Major
Jun 19, 2012, 7:35:41 AM6/19/12
to
In message
<643fdb40-eaac-4e5c...@6g2000vbv.googlegroups.com>,
marc.t...@wanadoo.fr writes
--
alias Ernest Major
<643fdb40-eaac-4e5c...@6g2000vbv.googlegroups.com>,
marc.t...@wanadoo.fr writes
>Do you agree with the calculation of the authors (see Appendix)? Then
>that "from simple considerations of energy and momentum conservation,
>(inelastic) light absorption transfers roughly one billion times as
>much energy per event from the visible to microwave bands, as competing
>elastic scattering processes, when the atoms participating in the two
>processes cycle between comparable (low) temperatures"?
Could you explain why you think that these claims are relevant.
>that "from simple considerations of energy and momentum conservation,
>(inelastic) light absorption transfers roughly one billion times as
>much energy per event from the visible to microwave bands, as competing
>elastic scattering processes, when the atoms participating in the two
>processes cycle between comparable (low) temperatures"?
--
alias Ernest Major
marc.t...@wanadoo.fr
Jun 19, 2012, 8:14:00 AM6/19/12
to
On Jun 19, 1:35 pm, Ernest Major <{$t...@meden.demon.co.uk> wrote:
> In message
> <643fdb40-eaac-4e5c-ac76-26e2cb66d...@6g2000vbv.googlegroups.com>,
> marc.tess...@wanadoo.fr writes
Moreover I think the entropy concept approach is useful to understand
the problems homo sapiens today is dealing with: the pollution and
particularly the greenhouse problem. To maintain the very high level
of organization of our species, homo sapiens and given the growing
overpopulation of this species there is a production of entropy
(pollution) which is significant relatively to our Earth ecosystem.
> In message
> <643fdb40-eaac-4e5c-ac76-26e2cb66d...@6g2000vbv.googlegroups.com>,
> marc.tess...@wanadoo.fr writes
>
> >Do you agree with the calculation of the authors (see Appendix)? Then
> >that "from simple considerations of energy and momentum conservation,
> >(inelastic) light absorption transfers roughly one billion times as
> >much energy per event from the visible to microwave bands, as competing
> >elastic scattering processes, when the atoms participating in the two
> >processes cycle between comparable (low) temperatures"?
>
> Could you explain why you think that these claims are relevant.
I would say because "with such a large multiplier per event, though,
> >Do you agree with the calculation of the authors (see Appendix)? Then
> >that "from simple considerations of energy and momentum conservation,
> >(inelastic) light absorption transfers roughly one billion times as
> >much energy per event from the visible to microwave bands, as competing
> >elastic scattering processes, when the atoms participating in the two
> >processes cycle between comparable (low) temperatures"?
>
> Could you explain why you think that these claims are relevant.
even a modest fraction of terrestrial matter rendered photosynthetic
by plants can produce a large enough change in energy transport to
power substantial chemical machinery".
by plants can produce a large enough change in energy transport to
Moreover I think the entropy concept approach is useful to understand
the problems homo sapiens today is dealing with: the pollution and
particularly the greenhouse problem. To maintain the very high level
of organization of our species, homo sapiens and given the growing
overpopulation of this species there is a production of entropy
(pollution) which is significant relatively to our Earth ecosystem.
Richard Norman
Jun 19, 2012, 10:41:21 AM6/19/12
to
On Tue, 19 Jun 2012 05:14:00 -0700 (PDT), marc.t...@wanadoo.fr
wrote:
Here you again mix several different concepts.
First, the quote. Light interacts with matter in several different
ways usually characterized by absorption, scattering, and
fluorescence. Your quote indicates that absorption is different from
scattering in the amount of energy transferred. It is very true that
the energy "yield" of absorption is far, far greater than that of
scattering. However the quote is somewhat deceptive by saying
"transferred from visible to microwave". The energy taken in by a
molecule or atom by absorption does not go into microwave radiation
but rather is captured as an elevated energy level in the electron
shell. That energy can then pass through a wide variety of pathways
to do useful work. Ultimately, that energy may get transferred to a
dissipative process and end up as heat at relatively low temperature
which produces microwave radiation. When a molelcule or atom is
involved in light scattering, it acquires such a tiny amount of energy
that it is almost always directly associated with kinetic energy --
motion-- and hence it goes directly into heat without doing useful
work. So light absorption, as opposed to scattering, is really
important of you want to do something with the energy in light
radiation.
So the main idea of that appendix is quite true although also quite
unnecessary since the idea is neither new nor in doubt. It is well
known.
Earnest Major's point still stands, though. This well known fact is
irrelevant. First, if you look at geophysical scales, the totality of
energy converted into heat from sunlight far exceeds the amount that
is absorbed to be used for photosynthesis. In the large scale, the
amount of energy absorbed by each individual interaction of a photon
with a molecule is completely meaningless. Second, there is no
shortage of inorganic pigment in the world which absorbs light just as
effectively as chlorophyll. I gave the example of basalt, a black
rock.
You say the absorption of light by living material to be enough to
power our entire substantial chemical machinery. So it is. But it
still pales in comparison to the purely physical processes at work in
the world. You ignore the arguments trying to show that the evolution
of life somehow is important to the overall thermodynamics of the
earth when I claim that all life's processes are a tiny flea in the
side of the massive inorganic thermodynamic processes of the earth. In
recent times, human activities have increased to such an extent to
cause a small tweak in global energy exchange. That small tweak is
enough to produce what seems to us to be total devastation. However
to the earth as a whole, a few degrees or tens of degrees temperature
difference of a few meters of water level is quite trivial -- there
have been previous cycles of much greater magnitude. That all life,
or just life as we know it, may be destroyed or at least substantially
changed is irrelevant. The earth has gone through previous major
extinction events without blinking, at least not in terms of its total
energy fluxes and entropy production.
You also somehow mix entropy with pollution, indicating that you do
not know what entropy really is in its technical use. That is why you
take so readily to arguments about thermodynamics applied to the earth
and to life in general. They fail when rigor is applied.
We know about pollution. We know about anthropogenic climate change.
We know about depeletion of natural resources. We know about
overpopulation. We know the causes and disastrous effects of all
these things, yet we seem to be powerless in changing the economic and
political and social factors that cause them. I do not see how adding
"entropy" or the laws of thermodynamics will help us solve or
understand these problems. By the way, I am not insensitive to all
these problems. That the "earth" doesn't care what happens to us
doesn't mean that WE shouldn't care. We shouldn't stop analyzing and
working on solutions. We absolutely must change. But adding to the
list of our problems the invalid notion of how we are increasing
"entropy" doesn't help.
wrote:
First, the quote. Light interacts with matter in several different
ways usually characterized by absorption, scattering, and
fluorescence. Your quote indicates that absorption is different from
scattering in the amount of energy transferred. It is very true that
the energy "yield" of absorption is far, far greater than that of
scattering. However the quote is somewhat deceptive by saying
"transferred from visible to microwave". The energy taken in by a
molecule or atom by absorption does not go into microwave radiation
but rather is captured as an elevated energy level in the electron
shell. That energy can then pass through a wide variety of pathways
to do useful work. Ultimately, that energy may get transferred to a
dissipative process and end up as heat at relatively low temperature
which produces microwave radiation. When a molelcule or atom is
involved in light scattering, it acquires such a tiny amount of energy
that it is almost always directly associated with kinetic energy --
motion-- and hence it goes directly into heat without doing useful
work. So light absorption, as opposed to scattering, is really
important of you want to do something with the energy in light
radiation.
So the main idea of that appendix is quite true although also quite
unnecessary since the idea is neither new nor in doubt. It is well
known.
Earnest Major's point still stands, though. This well known fact is
irrelevant. First, if you look at geophysical scales, the totality of
energy converted into heat from sunlight far exceeds the amount that
is absorbed to be used for photosynthesis. In the large scale, the
amount of energy absorbed by each individual interaction of a photon
with a molecule is completely meaningless. Second, there is no
shortage of inorganic pigment in the world which absorbs light just as
effectively as chlorophyll. I gave the example of basalt, a black
rock.
You say the absorption of light by living material to be enough to
power our entire substantial chemical machinery. So it is. But it
still pales in comparison to the purely physical processes at work in
the world. You ignore the arguments trying to show that the evolution
of life somehow is important to the overall thermodynamics of the
earth when I claim that all life's processes are a tiny flea in the
side of the massive inorganic thermodynamic processes of the earth. In
recent times, human activities have increased to such an extent to
cause a small tweak in global energy exchange. That small tweak is
enough to produce what seems to us to be total devastation. However
to the earth as a whole, a few degrees or tens of degrees temperature
difference of a few meters of water level is quite trivial -- there
have been previous cycles of much greater magnitude. That all life,
or just life as we know it, may be destroyed or at least substantially
changed is irrelevant. The earth has gone through previous major
extinction events without blinking, at least not in terms of its total
energy fluxes and entropy production.
You also somehow mix entropy with pollution, indicating that you do
not know what entropy really is in its technical use. That is why you
take so readily to arguments about thermodynamics applied to the earth
and to life in general. They fail when rigor is applied.
We know about pollution. We know about anthropogenic climate change.
We know about depeletion of natural resources. We know about
overpopulation. We know the causes and disastrous effects of all
these things, yet we seem to be powerless in changing the economic and
political and social factors that cause them. I do not see how adding
"entropy" or the laws of thermodynamics will help us solve or
understand these problems. By the way, I am not insensitive to all
these problems. That the "earth" doesn't care what happens to us
doesn't mean that WE shouldn't care. We shouldn't stop analyzing and
working on solutions. We absolutely must change. But adding to the
list of our problems the invalid notion of how we are increasing
"entropy" doesn't help.
marc.t...@wanadoo.fr
Jun 19, 2012, 11:14:31 AM6/19/12
to
On Jun 19, 4:41 pm, Richard Norman <r_s_nor...@comcast.net> wrote:
> On Tue, 19 Jun 2012 05:14:00 -0700 (PDT), marc.tess...@wanadoo.fr
I would be grateful if you could explain why there is no relationship
between the transformation of ordered things (like species, forests,
fossil fuels etc.) into much less ordered things like CO2 and an
increase of the entropy exported by our species to keep its own
entropy low.
> We know about pollution. We know about anthropogenic climate change.
> We know about depeletion of natural resources. We know about
> overpopulation. We know the causes and disastrous effects of all
> these things, yet we seem to be powerless in changing the economic and
> political and social factors that cause them. I do not see how adding
> "entropy" or the laws of thermodynamics will help us solve or
> understand these problems. By the way, I am not insensitive to all
> these problems. That the "earth" doesn't care what happens to us
> doesn't mean that WE shouldn't care. We shouldn't stop analyzing and
> working on solutions. We absolutely must change. But adding to the
> list of our problems the invalid notion of how we are increasing
> "entropy" doesn't help.- Hide quoted text -
> On Tue, 19 Jun 2012 05:14:00 -0700 (PDT), marc.tess...@wanadoo.fr
between the transformation of ordered things (like species, forests,
fossil fuels etc.) into much less ordered things like CO2 and an
increase of the entropy exported by our species to keep its own
entropy low.
> We know about pollution. We know about anthropogenic climate change.
> We know about depeletion of natural resources. We know about
> overpopulation. We know the causes and disastrous effects of all
> these things, yet we seem to be powerless in changing the economic and
> political and social factors that cause them. I do not see how adding
> "entropy" or the laws of thermodynamics will help us solve or
> understand these problems. By the way, I am not insensitive to all
> these problems. That the "earth" doesn't care what happens to us
> doesn't mean that WE shouldn't care. We shouldn't stop analyzing and
> working on solutions. We absolutely must change. But adding to the
> list of our problems the invalid notion of how we are increasing
Vend
Jun 19, 2012, 11:38:46 AM6/19/12
to
On 19 Giu, 17:14, marc.tess...@wanadoo.fr wrote:
> I would be grateful if you could explain why there is no relationship
> between the transformation of ordered things (like species, forests,
> fossil fuels etc.) into much less ordered things like CO2 and an
> increase of the entropy exported by our species to keep its own
> entropy low.
By burning fossil fuels, thus increasing the greenhouse effect and
> I would be grateful if you could explain why there is no relationship
> between the transformation of ordered things (like species, forests,
> fossil fuels etc.) into much less ordered things like CO2 and an
> increase of the entropy exported by our species to keep its own
> entropy low.
global temperature, we *reduce* the amount of entropy the Earth
exports to space.
We already pointed out that to you: higher temperature (given constant
albedo) => more exported entropy
marc.t...@wanadoo.fr
Jun 19, 2012, 12:51:41 PM6/19/12
to
is the entropy exported by our species which remains on the surface of
Earth and increases the entropy total in this local environment.
Richard Norman
Jun 19, 2012, 2:50:02 PM6/19/12
to
On Tue, 19 Jun 2012 08:14:31 -0700 (PDT), marc.t...@wanadoo.fr
wrote:
>On Jun 19, 4:41 pm, Richard Norman <r_s_nor...@comcast.net> wrote:
>> On Tue, 19 Jun 2012 05:14:00 -0700 (PDT), marc.tess...@wanadoo.fr
>> wrote:
<snip to retain only one single point quite distinct from the rest>
>> you
>> take so readily to arguments about thermodynamics applied to the earth
>> and to life in general. They fail when rigor is applied.
>
>I would be grateful if you could explain why there is no relationship
>between the transformation of ordered things (like species, forests,
>fossil fuels etc.) into much less ordered things like CO2 and an
>increase of the entropy exported by our species to keep its own
>entropy low.
You fall into a common fallacy of thinking that we living things "keep
our entropy low" by exporting it so that the totality of the entropy
in the universe can increase. Nothing gets exported. Consider
biology with constant temperature and pressure where Gibbs free energy
is appropriate. You can decrease entropy in a system by adding free
energy to it. That is, you can decrease entropy by doing work on it.
Nothing is exported.
In all systems, energy is conserved taking into account all inputs and
outputs. If you do work on a system (add energy to it) its internal
energy content must increase if nothing leaves. If the system is
conservative, that energy content exists somehow latent, as potential.
I can do work on a heavy object, lifting it from the floor to the
table. That energy is now present as gravitational potential energy
which can be released when the object later falls to the floor, but if
it stays on the table, that energy just sits there. There is no
entropy change in a conservative system. I can do work on a cell,
providing it with energy that the cell can use to build more cell,
creating macromolecules from smaller components and arranging them in
a specific structure. That creates "order". However no entropy was
exported either by lifting the weight nor by building the cell (I
ignore that the cell is not 100% "efficient".) The same happens with
an organism or an ecosystem. It can use its energy input to "increase
order" or "create negentropy" or "decrease entropy". However it
doesn't thereby export entropy to the outside.
If you allow a gas to expand, you can use it to do work and, if the
system is conservative, no entropy increases. Or you can allow the
gas to expand irreversibly in which case you do less or no work and
entropy increases. Using the expansion to do work does NOT cause a
compensatory increase in entropy elsewhere even if the work that you
do is to lower entropy here.
I think I can demonstrate the fallacy of the export concept with a
physical example. Consider an ordinary refrigerator. It takes in
electrical energy and decreases entropy by moving heat from a colder
region to a warmer one, cooling its inside and heating the outside.
"How can that be?" you ask. The answer is that the electric company
has a big generator that had to produce the electrical energy. Turning
on your refrigerator made the power company do more and so increases
the entropy there. But that is a false metaphor. The energy for
biological "negentropy" comes from the sun but the sun shines whether
there is anything living or not to use its energy. Turning on
photosynthesis has absolutely no effect on what happens in the sun.
Nothing is "exported" from the biological system because of
photosynthesis. All that happens is that the energy flow through the
system is temporarily diverted to do some useful work (create order)
rather than produce heat.
Or think of what I can do with a charged battery. I can use it to run
an electric motor that does lifts that object onto the table. Or I
can use it to just run the motor against a friction load without
lifting anything. In both cases the energy and thermodynamics of the
battery is identical: start with a charged battery and end with a
discharged one. In both cases the motor is identical: convert exactly
the same amount of electrical energy to mechanical. The difference is
that in one case I produce heat which is released to the environment
and entropy is increased. In the second, the object is lifted. The
entropy change is hidden, but decreased. Or, if you prefer, use the
motor to run the refrigerator so that entropy is decreased. Or use
the energy to run a biochemical system and create macromolecules and
"order". Doing useful work and transforming the input energy into
latent potential energy or "negentropy" or whatever does NOT export
entropy anywhere. And nowhere are the laws of thermodynamics
violated.
wrote:
>On Jun 19, 4:41 pm, Richard Norman <r_s_nor...@comcast.net> wrote:
>> On Tue, 19 Jun 2012 05:14:00 -0700 (PDT), marc.tess...@wanadoo.fr
>> wrote:
>> you
>> take so readily to arguments about thermodynamics applied to the earth
>> and to life in general. They fail when rigor is applied.
>
>I would be grateful if you could explain why there is no relationship
>between the transformation of ordered things (like species, forests,
>fossil fuels etc.) into much less ordered things like CO2 and an
>increase of the entropy exported by our species to keep its own
>entropy low.
our entropy low" by exporting it so that the totality of the entropy
in the universe can increase. Nothing gets exported. Consider
biology with constant temperature and pressure where Gibbs free energy
is appropriate. You can decrease entropy in a system by adding free
energy to it. That is, you can decrease entropy by doing work on it.
Nothing is exported.
In all systems, energy is conserved taking into account all inputs and
outputs. If you do work on a system (add energy to it) its internal
energy content must increase if nothing leaves. If the system is
conservative, that energy content exists somehow latent, as potential.
I can do work on a heavy object, lifting it from the floor to the
table. That energy is now present as gravitational potential energy
which can be released when the object later falls to the floor, but if
it stays on the table, that energy just sits there. There is no
entropy change in a conservative system. I can do work on a cell,
providing it with energy that the cell can use to build more cell,
creating macromolecules from smaller components and arranging them in
a specific structure. That creates "order". However no entropy was
exported either by lifting the weight nor by building the cell (I
ignore that the cell is not 100% "efficient".) The same happens with
an organism or an ecosystem. It can use its energy input to "increase
order" or "create negentropy" or "decrease entropy". However it
doesn't thereby export entropy to the outside.
If you allow a gas to expand, you can use it to do work and, if the
system is conservative, no entropy increases. Or you can allow the
gas to expand irreversibly in which case you do less or no work and
entropy increases. Using the expansion to do work does NOT cause a
compensatory increase in entropy elsewhere even if the work that you
do is to lower entropy here.
I think I can demonstrate the fallacy of the export concept with a
physical example. Consider an ordinary refrigerator. It takes in
electrical energy and decreases entropy by moving heat from a colder
region to a warmer one, cooling its inside and heating the outside.
"How can that be?" you ask. The answer is that the electric company
has a big generator that had to produce the electrical energy. Turning
on your refrigerator made the power company do more and so increases
the entropy there. But that is a false metaphor. The energy for
biological "negentropy" comes from the sun but the sun shines whether
there is anything living or not to use its energy. Turning on
photosynthesis has absolutely no effect on what happens in the sun.
Nothing is "exported" from the biological system because of
photosynthesis. All that happens is that the energy flow through the
system is temporarily diverted to do some useful work (create order)
rather than produce heat.
Or think of what I can do with a charged battery. I can use it to run
an electric motor that does lifts that object onto the table. Or I
can use it to just run the motor against a friction load without
lifting anything. In both cases the energy and thermodynamics of the
battery is identical: start with a charged battery and end with a
discharged one. In both cases the motor is identical: convert exactly
the same amount of electrical energy to mechanical. The difference is
that in one case I produce heat which is released to the environment
and entropy is increased. In the second, the object is lifted. The
entropy change is hidden, but decreased. Or, if you prefer, use the
motor to run the refrigerator so that entropy is decreased. Or use
the energy to run a biochemical system and create macromolecules and
"order". Doing useful work and transforming the input energy into
latent potential energy or "negentropy" or whatever does NOT export
entropy anywhere. And nowhere are the laws of thermodynamics
violated.
Vend
Jun 19, 2012, 4:38:36 PM6/19/12
to
warming?
Richard Norman
Jun 19, 2012, 5:19:30 PM6/19/12
to
On Tue, 19 Jun 2012 13:38:36 -0700 (PDT), Vend <ven...@virgilio.it>
It is a convoluted incorrect way of saying that we are causing global
warming. First, it is abuse of the word "entropy"; the very thing
Paul warned us about. Second, if the earth's temperature increases
then the conversion of incoming solar radiation into outgoing
microwave radiation represents a DEcrease in entropy from the current
level.
warming. First, it is abuse of the word "entropy"; the very thing
Paul warned us about. Second, if the earth's temperature increases
then the conversion of incoming solar radiation into outgoing
microwave radiation represents a DEcrease in entropy from the current
level.
marc.t...@wanadoo.fr
Jun 20, 2012, 4:08:19 AM6/20/12
to
On Jun 19, 8:50�pm, Richard Norman <r_s_nor...@comcast.net> wrote:
> You fall into a common fallacy of thinking that we living things "keep
> our entropy low" by exporting it so that the totality of the entropy
> in the universe can increase. �Nothing gets exported. �Consider
> You fall into a common fallacy of thinking that we living things "keep
> our entropy low" by exporting it so that the totality of the entropy
> biology with constant temperature and pressure where Gibbs free energy
> is appropriate. �You can decrease entropy in a system by adding free
> energy to it. �That is, you can decrease entropy by doing work on it.
> Nothing is exported.
>
> In all systems, energy is conserved taking into account all inputs and
> outputs. �If you do work on a system (add energy to it) its internal
>
> In all systems, energy is conserved taking into account all inputs and
> energy content must increase if nothing leaves. �If the system is
> conservative, that energy content exists somehow latent, as potential.
> I can do work on a heavy object, lifting it from the floor to the
> table. That energy is now present as gravitational potential energy
> which can be released when the object later falls to the floor, but if
> it stays on the table, that energy just sits there. There is no
> entropy change in a conservative system. �I can do work on a cell,
> I can do work on a heavy object, lifting it from the floor to the
> table. That energy is now present as gravitational potential energy
> which can be released when the object later falls to the floor, but if
> it stays on the table, that energy just sits there. There is no
> providing it with energy that the cell can use to build more cell,
> creating macromolecules from smaller components and arranging them in
> a specific structure. �That creates "order". �However no entropy was
> creating macromolecules from smaller components and arranging them in
> exported either by lifting the weight nor by building the cell (I
> ignore that the cell is not 100% "efficient".) �The same happens with
> an organism or an ecosystem. �It can use its energy input to "increase
> order" or "create negentropy" or "decrease entropy". �However it
> doesn't thereby export entropy to the outside.
>
> If you allow a gas to expand, you can use it to do work and, if the
> system is conservative, no entropy increases. �Or you can allow the
>
> If you allow a gas to expand, you can use it to do work and, if the
> gas to expand irreversibly in which case you do less or no work and
> entropy increases. �Using the expansion to do work does NOT cause a
> compensatory increase in entropy elsewhere even if the work that you
> do is to lower entropy here.
>
> I think I can demonstrate the fallacy of the export concept with a
> physical example. �Consider an ordinary refrigerator. �It takes in
> do is to lower entropy here.
>
> I think I can demonstrate the fallacy of the export concept with a
> electrical energy and decreases entropy by moving heat from a colder
> region to a warmer one, cooling its inside and heating the outside.
> "How can that be?" you ask. �The answer is that the electric company
> region to a warmer one, cooling its inside and heating the outside.
> has a big generator that had to produce the electrical energy. Turning
> on your refrigerator made the power company do more and so increases
> the entropy there. �But that is a false metaphor. �The energy for
> on your refrigerator made the power company do more and so increases
> biological "negentropy" comes from the sun but the sun shines whether
> there is anything living or not to use its energy. Turning on
> photosynthesis has absolutely no effect on what happens in the sun.
> Nothing is "exported" from the biological system because of
> photosynthesis. �All that happens is that the energy flow through the
> there is anything living or not to use its energy. Turning on
> photosynthesis has absolutely no effect on what happens in the sun.
> Nothing is "exported" from the biological system because of
> system is temporarily diverted to do some useful work (create order)
> rather than produce heat.
>
> Or think of what I can do with a charged battery. �I can use it to run
> rather than produce heat.
>
> an electric motor that does lifts that object onto the table. �Or I
> can use it to just run the motor against a friction load without
> lifting anything. �In both cases the energy and thermodynamics of the
> battery is identical: start with a charged battery and end with a
> discharged one. �In both cases the motor is identical: convert exactly
> the same amount of electrical energy to mechanical. �The difference is
> that in one case I produce heat which is released to the environment
> and entropy is increased. �In the second, the object is lifted. �The
> entropy change is hidden, but decreased. �Or, if you prefer, use the
> motor to run the refrigerator so that entropy is decreased. �Or use
> the energy to run a biochemical system and create macromolecules and
> "order". �Doing useful work and transforming the input energy into
> latent potential energy or "negentropy" or whatever does NOT export
> entropy anywhere. �And nowhere are the laws of thermodynamics
> violated.
Let us consider a relatively simple example of self-organization (SO)
like in the experiment based on the Belousov-Zhabotinski chemical
reaction (B-Z).
The experimental design needs to feed the B-Z system by chemical
products from the environment and to drain the synthesized by-products
towards the same environment.
Now , if you consider the whole closed system composed of the
experimental device (with the SO) and its environment, don�t you think
that the entropy change is an entropy increase over the time? In
particular the SO, to remain far-from-equilibrium, exports entropy
towards its environment by two mechanisms:
- the consumption of chemical products,
- the release of by-products.
(see �Negentropy� in Wikipedia: �The negentropy, also negative entropy
or syntropy or entaxy of a living system is the entropy that it
exports to keep its own entropy low�).
Richard Norman
Jun 20, 2012, 10:26:34 AM6/20/12
to
On Wed, 20 Jun 2012 01:08:19 -0700 (PDT), marc.t...@wanadoo.fr
wrote:
>On Jun 19, 8:50 pm, Richard Norman <r_s_nor...@comcast.net> wrote:
>> You fall into a common fallacy of thinking that we living things "keep
>> our entropy low" by exporting it so that the totality of the entropy
>> in the universe can increase. Nothing gets exported. Consider
>> energy to it. That is, you can decrease entropy by doing work on it.
>> energy content must increase if nothing leaves. If the system is
>> an organism or an ecosystem. It can use its energy input to "increase
>> order" or "create negentropy" or "decrease entropy". However it
>> an electric motor that does lifts that object onto the table. Or I
>> the same amount of electrical energy to mechanical. The difference is
>> entropy change is hidden, but decreased. Or, if you prefer, use the
>> motor to run the refrigerator so that entropy is decreased. Or use
I find it telling that a Google search for "export entropy" produces
sites involved in, in order or Google ranking, information systems,
artifician intelligence, ecological economics, your Wikipedia
"negentropy" site, a paper on maximum entropy production, economics,
resource management, a "metaphysical" cybernetics site, metallurgy.
What is strikingly absent is anything dealing with physical chemistry
or physics.
It certainly is true that the systems you like, self-sustaining
organized systems mainted far from equilibrium, must necessarily
involve a flow of matter and information through them and so there are
entropy changes in the outside world resulting from that flow. My
argument, which you seem to have missed, is that there are many
situations where the same flow occurs whether or not a self-sustaining
system intercepts it or not.
Your example is like my example of the refrigerator. It lowers
entropy by causing the power plant to increase entropy. The more you
run the refrigerator, the harder the power plant has to work. If you
want, you can say the refrigerator "exports" entropy to the power
plant. However return to my example of biology on earth. It "lowers
entropy" or "produces negentropy", if you insist, by tapping into the
power plant on the sun. However the sun goes on shining whether or
not there are plants on earth. Nothing that photosynthesis does
changes the thermodynamics of the sun. The only thing that
photosynthesis does is intercept sunlight so that is doesn't shine on
bare ground (or water). But if it did shine on bare ground or water,
the solar energy would simply be converted to heat, increasing
entropy. When the sunlight shines on a plant and some of that energy
is stored in chemical bonds in the synthesized sugar, does it produce
more heat or less heat? What is "exported" in photosynthesis. Are
you arguing that the conversion of oxygen to water is the "export"?
wrote:
>On Jun 19, 8:50 pm, Richard Norman <r_s_nor...@comcast.net> wrote:
>> You fall into a common fallacy of thinking that we living things "keep
>> our entropy low" by exporting it so that the totality of the entropy
>> biology with constant temperature and pressure where Gibbs free energy
>> is appropriate. You can decrease entropy in a system by adding free
>> energy to it. That is, you can decrease entropy by doing work on it.
>> Nothing is exported.
>>
>> In all systems, energy is conserved taking into account all inputs and
>> outputs. If you do work on a system (add energy to it) its internal
>>
>> In all systems, energy is conserved taking into account all inputs and
>> energy content must increase if nothing leaves. If the system is
>> conservative, that energy content exists somehow latent, as potential.
>> I can do work on a heavy object, lifting it from the floor to the
>> table. That energy is now present as gravitational potential energy
>> which can be released when the object later falls to the floor, but if
>> it stays on the table, that energy just sits there. There is no
>> entropy change in a conservative system. I can do work on a cell,
>> I can do work on a heavy object, lifting it from the floor to the
>> table. That energy is now present as gravitational potential energy
>> which can be released when the object later falls to the floor, but if
>> it stays on the table, that energy just sits there. There is no
>> providing it with energy that the cell can use to build more cell,
>> creating macromolecules from smaller components and arranging them in
>> a specific structure. That creates "order". However no entropy was
>> creating macromolecules from smaller components and arranging them in
>> exported either by lifting the weight nor by building the cell (I
>> ignore that the cell is not 100% "efficient".) The same happens with
>> an organism or an ecosystem. It can use its energy input to "increase
>> order" or "create negentropy" or "decrease entropy". However it
>> doesn't thereby export entropy to the outside.
>>
>> If you allow a gas to expand, you can use it to do work and, if the
>> system is conservative, no entropy increases. Or you can allow the
>>
>> If you allow a gas to expand, you can use it to do work and, if the
>> gas to expand irreversibly in which case you do less or no work and
>> entropy increases. Using the expansion to do work does NOT cause a
>> compensatory increase in entropy elsewhere even if the work that you
>> do is to lower entropy here.
>>
>> I think I can demonstrate the fallacy of the export concept with a
>> physical example. Consider an ordinary refrigerator. It takes in
>> do is to lower entropy here.
>>
>> I think I can demonstrate the fallacy of the export concept with a
>> electrical energy and decreases entropy by moving heat from a colder
>> region to a warmer one, cooling its inside and heating the outside.
>> "How can that be?" you ask. The answer is that the electric company
>> region to a warmer one, cooling its inside and heating the outside.
>> has a big generator that had to produce the electrical energy. Turning
>> on your refrigerator made the power company do more and so increases
>> the entropy there. But that is a false metaphor. The energy for
>> on your refrigerator made the power company do more and so increases
>> biological "negentropy" comes from the sun but the sun shines whether
>> there is anything living or not to use its energy. Turning on
>> photosynthesis has absolutely no effect on what happens in the sun.
>> Nothing is "exported" from the biological system because of
>> photosynthesis. All that happens is that the energy flow through the
>> there is anything living or not to use its energy. Turning on
>> photosynthesis has absolutely no effect on what happens in the sun.
>> Nothing is "exported" from the biological system because of
>> system is temporarily diverted to do some useful work (create order)
>> rather than produce heat.
>>
>> Or think of what I can do with a charged battery. I can use it to run
>> rather than produce heat.
>>
>> an electric motor that does lifts that object onto the table. Or I
>> can use it to just run the motor against a friction load without
>> lifting anything. In both cases the energy and thermodynamics of the
>> battery is identical: start with a charged battery and end with a
>> discharged one. In both cases the motor is identical: convert exactly
>> the same amount of electrical energy to mechanical. The difference is
>> that in one case I produce heat which is released to the environment
>> and entropy is increased. In the second, the object is lifted. The
>> entropy change is hidden, but decreased. Or, if you prefer, use the
>> motor to run the refrigerator so that entropy is decreased. Or use
>> the energy to run a biochemical system and create macromolecules and
>> "order". Doing useful work and transforming the input energy into
>> latent potential energy or "negentropy" or whatever does NOT export
>> entropy anywhere. And nowhere are the laws of thermodynamics
>> violated.
>
>Let us consider a relatively simple example of self-organization (SO)
>like in the experiment based on the Belousov-Zhabotinski chemical
>reaction (B-Z).
>The experimental design needs to feed the B-Z system by chemical
>products from the environment and to drain the synthesized by-products
>towards the same environment.
>Now , if you consider the whole closed system composed of the
>experimental device (with the SO) and its environment, don’t you think
>
>Let us consider a relatively simple example of self-organization (SO)
>like in the experiment based on the Belousov-Zhabotinski chemical
>reaction (B-Z).
>The experimental design needs to feed the B-Z system by chemical
>products from the environment and to drain the synthesized by-products
>towards the same environment.
>Now , if you consider the whole closed system composed of the
>that the entropy change is an entropy increase over the time? In
>particular the SO, to remain far-from-equilibrium, exports entropy
>towards its environment by two mechanisms:
>- the consumption of chemical products,
>- the release of by-products.
>(see “Negentropy” in Wikipedia: “The negentropy, also negative entropy
>particular the SO, to remain far-from-equilibrium, exports entropy
>towards its environment by two mechanisms:
>- the consumption of chemical products,
>- the release of by-products.
>or syntropy or entaxy of a living system is the entropy that it
>exports to keep its own entropy low”).
I find it telling that a Google search for "export entropy" produces
sites involved in, in order or Google ranking, information systems,
artifician intelligence, ecological economics, your Wikipedia
"negentropy" site, a paper on maximum entropy production, economics,
resource management, a "metaphysical" cybernetics site, metallurgy.
What is strikingly absent is anything dealing with physical chemistry
or physics.
It certainly is true that the systems you like, self-sustaining
organized systems mainted far from equilibrium, must necessarily
involve a flow of matter and information through them and so there are
entropy changes in the outside world resulting from that flow. My
argument, which you seem to have missed, is that there are many
situations where the same flow occurs whether or not a self-sustaining
system intercepts it or not.
Your example is like my example of the refrigerator. It lowers
entropy by causing the power plant to increase entropy. The more you
run the refrigerator, the harder the power plant has to work. If you
want, you can say the refrigerator "exports" entropy to the power
plant. However return to my example of biology on earth. It "lowers
entropy" or "produces negentropy", if you insist, by tapping into the
power plant on the sun. However the sun goes on shining whether or
not there are plants on earth. Nothing that photosynthesis does
changes the thermodynamics of the sun. The only thing that
photosynthesis does is intercept sunlight so that is doesn't shine on
bare ground (or water). But if it did shine on bare ground or water,
the solar energy would simply be converted to heat, increasing
entropy. When the sunlight shines on a plant and some of that energy
is stored in chemical bonds in the synthesized sugar, does it produce
more heat or less heat? What is "exported" in photosynthesis. Are
you arguing that the conversion of oxygen to water is the "export"?
marc.t...@wanadoo.fr
Jun 20, 2012, 11:03:47 AM6/20/12
to
On Jun 20, 4:26 pm, Richard Norman <r_s_nor...@comcast.net> wrote:
> I find it telling that a Google search for "export entropy" produces
> sites involved in, in order or Google ranking, information systems,
> artifician intelligence, ecological economics, your Wikipedia
> "negentropy" site, a paper on maximum entropy production, economics,
> resource management, a "metaphysical" cybernetics site, metallurgy.
>
> What is strikingly absent is anything dealing with physical chemistry
> or physics.
>
> It certainly is true that the systems you like, self-sustaining
> organized systems mainted far from equilibrium, must necessarily
> involve a flow of matter and information through them and so there are
> entropy changes in the outside world resulting from that flow. My
> argument, which you seem to have missed, is that there are many
> situations where the same flow occurs whether or not a self-sustaining
> system intercepts it or not.
>
> Your example is like my example of the refrigerator. It lowers
> entropy by causing the power plant to increase entropy. The more you
> run the refrigerator, the harder the power plant has to work. If you
> want, you can say the refrigerator "exports" entropy to the power
> plant. However return to my example of biology on earth. It "lowers
> entropy" or "produces negentropy", if you insist, by tapping into the
> power plant on the sun. However the sun goes on shining whether or
> not there are plants on earth.
When the sun provides its environment (and for only a part the Earth)
> I find it telling that a Google search for "export entropy" produces
> sites involved in, in order or Google ranking, information systems,
> artifician intelligence, ecological economics, your Wikipedia
> "negentropy" site, a paper on maximum entropy production, economics,
> resource management, a "metaphysical" cybernetics site, metallurgy.
>
> What is strikingly absent is anything dealing with physical chemistry
> or physics.
>
> It certainly is true that the systems you like, self-sustaining
> organized systems mainted far from equilibrium, must necessarily
> involve a flow of matter and information through them and so there are
> entropy changes in the outside world resulting from that flow. My
> argument, which you seem to have missed, is that there are many
> situations where the same flow occurs whether or not a self-sustaining
> system intercepts it or not.
>
> Your example is like my example of the refrigerator. It lowers
> entropy by causing the power plant to increase entropy. The more you
> run the refrigerator, the harder the power plant has to work. If you
> want, you can say the refrigerator "exports" entropy to the power
> plant. However return to my example of biology on earth. It "lowers
> entropy" or "produces negentropy", if you insist, by tapping into the
> power plant on the sun. However the sun goes on shining whether or
> not there are plants on earth.
with energy (photons) its entropy increases as the sun progressively
but inexorably approaches its thermodynamic equilibrium over time.
When considering photosynthesis by organisms we must take the sun's
entropy increase into account in the total balance of entropy (as the
sun is part of the whole closed system composed of the Earth surface
with its photosynthetic organisms and the sun).
> Nothing that photosynthesis does
> changes the thermodynamics of the sun. The only thing that
> photosynthesis does is intercept sunlight so that is doesn't shine on
> bare ground (or water). But if it did shine on bare ground or water,
> the solar energy would simply be converted to heat, increasing
> entropy. When the sunlight shines on a plant and some of that energy
> is stored in chemical bonds in the synthesized sugar, does it produce
> more heat or less heat? What is "exported" in photosynthesis. Are
Richard Norman
Jun 20, 2012, 11:16:02 AM6/20/12
to
On Wed, 20 Jun 2012 08:03:47 -0700 (PDT), marc.t...@wanadoo.fr
wrote:
I fully agree that the "negentropy" of living things is depends on the
increase in entropy in the sun. However, if you say that life
"exports entropy" to the sun, you also have to say that rocks warming
in the sun also "export entropy". If that is the case, then the
export of entropy has no value in understanding anything. It is just
the reverse side of saying that things absorb energy from the sun.
The real issue is not export or import but whether talking about
processes in terms of entropy has no real value in helping us
understand those processes. What is important is what the processes
do with the energy and material flows that they tap into. We all know
that the processes we both are interested in do tap into energy and
material flows and that entropy changes are involved in those flows.
If rocks export entropy just as much as plants do, then what have we
gained about understanding life from talking about entropy export?
wrote:
increase in entropy in the sun. However, if you say that life
"exports entropy" to the sun, you also have to say that rocks warming
in the sun also "export entropy". If that is the case, then the
export of entropy has no value in understanding anything. It is just
the reverse side of saying that things absorb energy from the sun.
The real issue is not export or import but whether talking about
processes in terms of entropy has no real value in helping us
understand those processes. What is important is what the processes
do with the energy and material flows that they tap into. We all know
that the processes we both are interested in do tap into energy and
material flows and that entropy changes are involved in those flows.
If rocks export entropy just as much as plants do, then what have we
gained about understanding life from talking about entropy export?
marc.t...@wanadoo.fr
Jun 20, 2012, 11:52:32 AM6/20/12
to
On Jun 20, 5:16 pm, Richard Norman <r_s_nor...@comcast.net> wrote:
> I fully agree that the "negentropy" of living things is depends on the
> increase in entropy in the sun. However, if you say that life
> "exports entropy" to the sun, you also have to say that rocks warming
> in the sun also "export entropy". If that is the case, then the
> export of entropy has no value in understanding anything. It is just
> the reverse side of saying that things absorb energy from the sun.
I don't say that the photosynthetic organisms "exports entropy" to the
> I fully agree that the "negentropy" of living things is depends on the
> increase in entropy in the sun. However, if you say that life
> "exports entropy" to the sun, you also have to say that rocks warming
> in the sun also "export entropy". If that is the case, then the
> export of entropy has no value in understanding anything. It is just
> the reverse side of saying that things absorb energy from the sun.
sun.
In the entropy balance I see the following:
- there is a production of negentropy (of organization) to maintain
the photosynthetic organisms far-from-equilibrium;
- there is a production of entropy by the photosynthetic organisms by
two mechanisms:
1) the production of a by-product, oxygen gaz (if we only consider
photosynthesis) towards the Earth surface,
2) the consumption of carbon di-oxyde, nitrates etc.
The total production of entropy (the sun entropy increase included)
must exceed the production of negentropy.
> The real issue is not export or import but whether talking about
> processes in terms of entropy has no real value in helping us
> understand those processes. What is important is what the processes
> do with the energy and material flows that they tap into. We all know
> that the processes we both are interested in do tap into energy and
> material flows and that entropy changes are involved in those flows.
> If rocks export entropy just as much as plants do, then what have we
> gained about understanding life from talking about entropy export?
understanding evolution from talking about entropy?
Actually this is the subject of my next article (!)
Richard Norman
Jun 20, 2012, 12:39:57 PM6/20/12
to
On Wed, 20 Jun 2012 08:52:32 -0700 (PDT), marc.t...@wanadoo.fr
wrote:
>On Jun 20, 5:16 pm, Richard Norman <r_s_nor...@comcast.net> wrote:
>> I fully agree that the "negentropy" of living things is depends on the
>> increase in entropy in the sun. However, if you say that life
>> "exports entropy" to the sun, you also have to say that rocks warming
>> in the sun also "export entropy". If that is the case, then the
>> export of entropy has no value in understanding anything. It is just
>> the reverse side of saying that things absorb energy from the sun.
>
>I don't say that the photosynthetic organisms "exports entropy" to the
>sun.
>In the entropy balance I see the following:
>- there is a production of negentropy (of organization) to maintain
>the photosynthetic organisms far-from-equilibrium;
>- there is a production of entropy by the photosynthetic organisms by
>two mechanisms:
>1) the production of a by-product, oxygen gaz (if we only consider
>photosynthesis) towards the Earth surface,
>2) the consumption of carbon di-oxyde, nitrates etc.
>The total production of entropy (the sun entropy increase included)
>must exceed the production of negentropy.
>
<snip the more important question of what we learn about evolution
from looking at entropy until your article on the subject appears.
That will give us more information to discuss.>
My point is that studying the production of the by-products and the
consumption of the substrates and the analysis of how are where energy
is consumed tells us far more about the processes of photosynthesis
and how it fits into a larger scheme of things than does an analysis
of entropy or "negentropy". Incidentally, I always put that term in
quotes because I have never seen a consistent, technically and
quantitatively accurate definition of exactly what is is and how to
measure exactly how much of it you have. It appears as mysterious to
me as does the notion of "life" to you.
To be more specific: plant physiologists are concerned with the
mechanism of photosynthesis and how the substrates are provided and
how the products are distributed and used. They are also concerned
with a general energy budget of plants: the rate at which
photosynthesis exceeds respiration to result in net primary
productivity and then how this productivity is used for growth and
development and reproduction. Ecologists are interested in how net
primary productivity (in plants) is used by herbivores or
scavengers-decomposers in food webs and nets. The rate of net
production or consumption of biomass is an important subject. The use
of energy is an important subject. The cycling of matter is an
imporant subject. I do not see how these topics are improved by
recasting exactly the same information in terms of entropy.
wrote:
>On Jun 20, 5:16 pm, Richard Norman <r_s_nor...@comcast.net> wrote:
>> I fully agree that the "negentropy" of living things is depends on the
>> increase in entropy in the sun. However, if you say that life
>> "exports entropy" to the sun, you also have to say that rocks warming
>> in the sun also "export entropy". If that is the case, then the
>> export of entropy has no value in understanding anything. It is just
>> the reverse side of saying that things absorb energy from the sun.
>
>I don't say that the photosynthetic organisms "exports entropy" to the
>sun.
>In the entropy balance I see the following:
>- there is a production of negentropy (of organization) to maintain
>the photosynthetic organisms far-from-equilibrium;
>- there is a production of entropy by the photosynthetic organisms by
>two mechanisms:
>1) the production of a by-product, oxygen gaz (if we only consider
>photosynthesis) towards the Earth surface,
>2) the consumption of carbon di-oxyde, nitrates etc.
>The total production of entropy (the sun entropy increase included)
>must exceed the production of negentropy.
>
from looking at entropy until your article on the subject appears.
That will give us more information to discuss.>
My point is that studying the production of the by-products and the
consumption of the substrates and the analysis of how are where energy
is consumed tells us far more about the processes of photosynthesis
and how it fits into a larger scheme of things than does an analysis
of entropy or "negentropy". Incidentally, I always put that term in
quotes because I have never seen a consistent, technically and
quantitatively accurate definition of exactly what is is and how to
measure exactly how much of it you have. It appears as mysterious to
me as does the notion of "life" to you.
To be more specific: plant physiologists are concerned with the
mechanism of photosynthesis and how the substrates are provided and
how the products are distributed and used. They are also concerned
with a general energy budget of plants: the rate at which
photosynthesis exceeds respiration to result in net primary
productivity and then how this productivity is used for growth and
development and reproduction. Ecologists are interested in how net
primary productivity (in plants) is used by herbivores or
scavengers-decomposers in food webs and nets. The rate of net
production or consumption of biomass is an important subject. The use
of energy is an important subject. The cycling of matter is an
imporant subject. I do not see how these topics are improved by
recasting exactly the same information in terms of entropy.
marc.t...@wanadoo.fr
Jun 21, 2012, 12:09:07 PM6/21/12
to
On Jun 20, 6:39 pm, Richard Norman <r_s_nor...@comcast.net> wrote:
> the more important question of what we learn about evolution
> from looking at entropy until your article on the subject appears.
> That will give us more information to discuss.
>
> My point is that studying the production of the by-products and the
> consumption of the substrates and the analysis of how are where energy
> is consumed tells us far more about the processes of photosynthesis
> and how it fits into a larger scheme of things than does an analysis
> of entropy or "negentropy". Incidentally, I always put that term in
> quotes because I have never seen a consistent, technically and
> quantitatively accurate definition of exactly what is is and how to
> measure exactly how much of it you have. It appears as mysterious to
> me as does the notion of "life" to you.
I agree with you that entropy is apparently quite a complex notion.
> the more important question of what we learn about evolution
> from looking at entropy until your article on the subject appears.
> That will give us more information to discuss.
>
> My point is that studying the production of the by-products and the
> consumption of the substrates and the analysis of how are where energy
> is consumed tells us far more about the processes of photosynthesis
> and how it fits into a larger scheme of things than does an analysis
> of entropy or "negentropy". Incidentally, I always put that term in
> quotes because I have never seen a consistent, technically and
> quantitatively accurate definition of exactly what is is and how to
> measure exactly how much of it you have. It appears as mysterious to
> me as does the notion of "life" to you.
However I think the statistical thermodynamics approach may be a
simple and useful one.
Then, under the hypothesis that any microstate is assumed to be
equally probable (this assumption is usually justified for an isolated
system in equilibrium, i.e., such a system is one in which the volume,
number of molecules, and internal energy are fixed) we have the
following equality:
S=Kb lnΩ (where S is entropy, Kb the Boltzmann constant and Ω the
number of *possible microstates* of the system).
Then let us firstly consider the following experiment (I am sure you
know this example):
- a monomolecular gaz is confined in a volume V of a closed cylinder
C1;
- another cylinder C2 (same volume V) is linked to C1 by a small
channel on which there is a tap;
- at t1 the tap is closed and there is avuum in C2: then the entropy
of the system is S;
- then the tap is opened;
- at t2, once the equilibrium is reached, the monomolecular gaz now
fills C1 and C2, i.e., volume 2V.
Do you agree that the number of the possible microstates doubled and
then that entropy doubled too?
The same approach may be used in the example of the system based on
the Belousov-Zhabotinski chemical reaction (B-Z):
- the maintenance of the organization of the B-Z self-organization
(SO) corresponds to a constraint on the molecules of the system. Then
the molecules which are involved in the SO reduce their degree of
freedom and the number of possible microstates of the molecules
involved in the SO is much lower in comparison with a random
distribution of these molecules;
- on the contrary the consumption of relatively elaborated molecules
(the products which are provided to the system by a reactor) which are
transformed into less elaborated molecules (the by-products) which are
released in the environment corresponds to an increase of the degree
of freedom of all the molecules. Then the number of possible
microstates of the total system (composed of all the molecules)
increases.
> To be more specific: plant physiologists are concerned with the
> mechanism of photosynthesis and how the substrates are provided and
> how the products are distributed and used. They are also concerned
> with a general energy budget of plants: the rate at which
> photosynthesis exceeds respiration to result in net primary
> productivity and then how this productivity is used for growth and
> development and reproduction. Ecologists are interested in how net
> primary productivity (in plants) is used by herbivores or
> scavengers-decomposers in food webs and nets. The rate of net
> production or consumption of biomass is an important subject. The use
> of energy is an important subject. The cycling of matter is an
> imporant subject. I do not see how these topics are improved by
Richard Norman
Jun 21, 2012, 12:51:41 PM6/21/12
to
On Thu, 21 Jun 2012 09:09:07 -0700 (PDT), marc.t...@wanadoo.fr
wrote:
>On Jun 20, 6:39 pm, Richard Norman <r_s_nor...@comcast.net> wrote:
>> the more important question of what we learn about evolution
>> from looking at entropy until your article on the subject appears.
>> That will give us more information to discuss.
>>
>> My point is that studying the production of the by-products and the
>> consumption of the substrates and the analysis of how are where energy
>> is consumed tells us far more about the processes of photosynthesis
>> and how it fits into a larger scheme of things than does an analysis
>> of entropy or "negentropy". Incidentally, I always put that term in
>> quotes because I have never seen a consistent, technically and
>> quantitatively accurate definition of exactly what is is and how to
>> measure exactly how much of it you have. It appears as mysterious to
>> me as does the notion of "life" to you.
>
>I agree with you that entropy is apparently quite a complex notion.
>However I think the statistical thermodynamics approach may be a
>simple and useful one.
>Then, under the hypothesis that any microstate is assumed to be
>equally probable (this assumption is usually justified for an isolated
>system in equilibrium, i.e., such a system is one in which the volume,
>number of molecules, and internal energy are fixed) we have the
>following equality:
>
>S=Kb ln? (where S is entropy, Kb the Boltzmann constant and ? the
<snip examples of how biologists usually focus on the pathways a
system takes rather than on the final state, specifically, the
entropy>
Your example of a gas expanding irreversibly fails. Suppose, instead,
you confine it to half a chamber with a piston. You now allow it to
expand reversibly pushing the piston which runs an electrical
generator to charge a capacitor. The gas initially occupied one
volume but now occupies twice the volume. Certainly there more twice
as many microstates, no? But this time there is ZERO change of
entropy. There is more going on. A lot more that you have to take
into consideration. For one thing, you have omitted the velocity
distribution of the gas particles (temperature).
Counting microstates, especially in the B-Z system, is far more
complex than you describe. You have to account for changes in the
number of each chemical species and the changes in the type of
chemical bonding in each reaction and changes in the internal energy
of vibration and rotation for each degree of freedom. No, trying to
track entropy by counting microstates in any real physical process is
a losing task.
Once again, I do not deny that entropy changes in any realistic
physical process (truly reversible reactions in the macro world are
more conceptual than physically realizable, although we can come very
close). I do not deny that the details about how energy and entropy
change are different for systems that can self-organize than for
systems that tend to dissipate. What I claim is that looking at
entropy is not a good way of seeing just how self-organizing systems
do what they do; looking at details of energy utilization and
mechanicsm of coupling between different components of the system are
more useful. We do not look at entropy when examining the relative
merits of carbohydrate vs. lipid is a metabolic substrate; we look at
kJ/mol or kJ/g of Gibbs free energy.
wrote:
>On Jun 20, 6:39 pm, Richard Norman <r_s_nor...@comcast.net> wrote:
>> the more important question of what we learn about evolution
>> from looking at entropy until your article on the subject appears.
>> That will give us more information to discuss.
>>
>> My point is that studying the production of the by-products and the
>> consumption of the substrates and the analysis of how are where energy
>> is consumed tells us far more about the processes of photosynthesis
>> and how it fits into a larger scheme of things than does an analysis
>> of entropy or "negentropy". Incidentally, I always put that term in
>> quotes because I have never seen a consistent, technically and
>> quantitatively accurate definition of exactly what is is and how to
>> measure exactly how much of it you have. It appears as mysterious to
>> me as does the notion of "life" to you.
>
>I agree with you that entropy is apparently quite a complex notion.
>However I think the statistical thermodynamics approach may be a
>simple and useful one.
>Then, under the hypothesis that any microstate is assumed to be
>equally probable (this assumption is usually justified for an isolated
>system in equilibrium, i.e., such a system is one in which the volume,
>number of molecules, and internal energy are fixed) we have the
>following equality:
>
system takes rather than on the final state, specifically, the
entropy>
Your example of a gas expanding irreversibly fails. Suppose, instead,
you confine it to half a chamber with a piston. You now allow it to
expand reversibly pushing the piston which runs an electrical
generator to charge a capacitor. The gas initially occupied one
volume but now occupies twice the volume. Certainly there more twice
as many microstates, no? But this time there is ZERO change of
entropy. There is more going on. A lot more that you have to take
into consideration. For one thing, you have omitted the velocity
distribution of the gas particles (temperature).
Counting microstates, especially in the B-Z system, is far more
complex than you describe. You have to account for changes in the
number of each chemical species and the changes in the type of
chemical bonding in each reaction and changes in the internal energy
of vibration and rotation for each degree of freedom. No, trying to
track entropy by counting microstates in any real physical process is
a losing task.
Once again, I do not deny that entropy changes in any realistic
physical process (truly reversible reactions in the macro world are
more conceptual than physically realizable, although we can come very
close). I do not deny that the details about how energy and entropy
change are different for systems that can self-organize than for
systems that tend to dissipate. What I claim is that looking at
entropy is not a good way of seeing just how self-organizing systems
do what they do; looking at details of energy utilization and
mechanicsm of coupling between different components of the system are
more useful. We do not look at entropy when examining the relative
merits of carbohydrate vs. lipid is a metabolic substrate; we look at
kJ/mol or kJ/g of Gibbs free energy.
marc.t...@wanadoo.fr
Jun 22, 2012, 1:57:30 PM6/22/12
to
On 21 juin, 18:51, Richard Norman <r_s_nor...@comcast.net> wrote:
> Your example of a gas expanding irreversibly fails.
Why do you say my example fails? Actually it doesn't as long as there
> Your example of a gas expanding irreversibly fails.
is no work, and I agree with you on that point.
In my example there is no work, then, if U is the internal energy of
the system, du = 0. Then, if S is the entropy of the system, ΔS = n R
ln 2V/V = nR ln2 (actually I was wrong to write that S doubled).
But you are right that, when there is work (your example with a
piston), it is no more possible to have a reasoning based on the
number of microstates. Actually, you are right, the calculation gives
ΔS = 0.
Richard Norman
Jun 22, 2012, 3:41:51 PM6/22/12
to
On Fri, 22 Jun 2012 10:57:30 -0700 (PDT), marc.t...@wanadoo.fr
wrote:
>On 21 juin, 18:51, Richard Norman <r_s_nor...@comcast.net> wrote:
>> Your example of a gas expanding irreversibly fails.
>
>Why do you say my example fails? Actually it doesn't as long as there
>is no work, and I agree with you on that point.
>In my example there is no work, then, if U is the internal energy of
>the system, du = 0. Then, if S is the entropy of the system, ?S = n R
>
What do you mean by "work"? In the expanding gas situation, it is
mechanical work against load. In the biological situation, it is
synthesis of new chemicals and organizing them in specified ways to
produce structure. If you agree that "doing work" means you can't
argue based easily on counting microstates, then nothing interesting
in the world happens that you can apply your argument to. All of
self-organization is the tapping into a flux of energy to allow a
portion of a system to tend towards equilibrium so that it can do the
work of organizing and maintaining the remaining part of the system
that is self-organizing and self-sustaining.
If you say you want to study the energy flows and coupling mechanisms
by which that energy is channeled into doing the job then I am in
complete agreement. If you say you want to study entropy production
because that gives you a clue as to how it works, I say Ggood luck.
Come back when you have it done but I won't hold my breath waiting."
wrote:
>On 21 juin, 18:51, Richard Norman <r_s_nor...@comcast.net> wrote:
>> Your example of a gas expanding irreversibly fails.
>
>Why do you say my example fails? Actually it doesn't as long as there
>is no work, and I agree with you on that point.
>In my example there is no work, then, if U is the internal energy of
>ln 2V/V = nR ln2 (actually I was wrong to write that S doubled).
>
>But you are right that, when there is work (your example with a
>piston), it is no more possible to have a reasoning based on the
>number of microstates. Actually, you are right, the calculation gives
>?S = 0.
>
>But you are right that, when there is work (your example with a
>piston), it is no more possible to have a reasoning based on the
>number of microstates. Actually, you are right, the calculation gives
>
What do you mean by "work"? In the expanding gas situation, it is
mechanical work against load. In the biological situation, it is
synthesis of new chemicals and organizing them in specified ways to
produce structure. If you agree that "doing work" means you can't
argue based easily on counting microstates, then nothing interesting
in the world happens that you can apply your argument to. All of
self-organization is the tapping into a flux of energy to allow a
portion of a system to tend towards equilibrium so that it can do the
work of organizing and maintaining the remaining part of the system
that is self-organizing and self-sustaining.
If you say you want to study the energy flows and coupling mechanisms
by which that energy is channeled into doing the job then I am in
complete agreement. If you say you want to study entropy production
because that gives you a clue as to how it works, I say Ggood luck.
Come back when you have it done but I won't hold my breath waiting."
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