how reptiles evolved to humans

[eridanus]

How Reptiles Evolved to Form Humans Full Documentary
https://www.youtube.com/watch?v=ShxoM5ujw1k

here is a part on min 35 that starts something interesting about
how the skin cells have some variations, that produce nails, teeth,
sweat glands, hair, etc. Around this part, it presents a man that
suffers from a rare mutation that do not have nails, or barely in a few
of his finger. He had only a few teeth that had to be taken away for it
was causing him problems. He had not any hair on his body of sweat
glands. All these elements are some variety of skin cells, that for
whatever reason do not worked.


Then, talking about other subject, I remember a very sportive girl,
that was very good running, and won some races. She got a boy and married.
They got worried because she could not get pregnant. After a number of
analysis it resulted that his sexual chromosomes were XY. The doc said
that even in she had all the appearance of a woman, he was really a man
and had testicles in the place of ovaries. But other wise she had all
the external appearances of being a female. I observed in the video
that the face of this girl look like she had too much testosterone, not
only by the power of his jaw, but also in general she has a strong body
like she were a male athlete.
So, when we talk about genes, several different genes can be altered
and it occur this sort of phenomenon. Some of the mutations are not
helping the person, even if they are not lethal. A bad mutation in some
part and something can get wrong. This looks like the argument of the
creationist arguing about the scarce probabilities of something good
to occur. This is false. So far as mutations do not alter some
important genes everything goes according to some well known formula.

The question that remains is to prove how a well functioning organism
can change so much as to be "a little bit different". This is the way
I suppose evolution works with mutations. The change must be almost
compatible with the general plan of the species. A few changes are
possible if they are not altering the general plan. By changing in
little steps, they can accumulate some serious amount of differences
after a time. How long a time? This is a problem, I think, we have
had not yet solved.
Anyway, the video have some interesting points, easy to watch and to
understand.
There is also the problem not yet solved, I suppose is not yet solved,
about when occur most or the changes in the genome of living organisms.

If we believe the fragmentary fossil record, most of the proliferation
of new species had occurred after some periods of serious extinctions.
It is this a necessary condition? Or can this happen in all periods of
time, far away from the moments of extinctions? Well, perhaps Ron can
tell us. He seems to be the guru of evolution here.

Eri

[Mike Duffy]

On Tue, 25 Oct 2016 10:20:00 -0700 (PDT), eridanus wrote:

> Well, perhaps Ron can tell us.
> He seems to be the guru of evolution here.

He does have a good general grasp of the basics. There are no doubt others
who have a more refined background in specific areas of expertise, but
Ron's forté in my opinion is simply being to explain things to those of us
who do not have a strong knowledge of life sciences.

Some of the others who are habitual posters here have a tendency to use
terminology requiring active web research for someone who has never studied
biology at a post-secondary level. For sure, we learn more from such
posters, but it can become tedious.


Despite my lack of any articles I can quote for reference, I will take a
stab at your question. I think the proliferation of adaptations (and
consequent speciation) is the result of a newly uninhabited environment.

And a newly uninhabited environment can be either a completely new
environment, or an existing environment which has recently become
depopulated, usually due to a temporary catastropy.

NB: On a geologic scale, human civilization is a temporary catastrophy.

[eridanus]

i have not any problems with evolution
eri

[rsNorman]

Mike Duffy <mqduf...@bell.net> Wrote in message:

No doubt I am one of those others you describe and my only excuse
is that I spent many decades explaining these things solely to
people who have, indeed, studied biology at a post-secondary
level. The pattern is hard to break.

There are technical terms relating to what you describe as an
"uninhabited environment": habitat and niche. If you mean by
environment a physical region -- an area of land, a lake or pond
-- that is "habitat." It is quite true that the few pioneers
that enter such an uninhabited region will proliferate and
diversify into new species just as you describe. That is called
"adaptive radiation." The process of ecological changes on land
that follow from life entering a truly new habitat that did not
previously sustain any life, no soil, is called "primary
succession." After a catastrophe like a fire or flood or even
human intervention like an abandoned farm or clear cut foresting,
it is called "secondary succession."

There is another process, though, which is probably more to the
point when it comes to lizards evolving into humans and that
involves the concept of "niche." That includes the notion of how
organisms use their resources. If you figure out a way to use
the resources in an already existing environment already
populated by all sorts of living things but in a different way
than they do then you can extract nutrients and nesting sites and
other forms of existence that were there all the time but were
not being utilized. It is sometimes said that "habitat" is your
address but "niche" is your occupation, how you make a living.
New people can move into your neighborhood, sharing your general
address, but if they run a different kind of business then they
are not really in competition with you and you can coexist
nicely.


--


----Android NewsGroup Reader----
http://usenet.sinaapp.com/

[eridanus]

Thank you rnorman. All this is well known already, at least for me.
What is not easy to explain is the evolution at a genetic level for
division of a species in two. As I told in another part, this is an
abstract view of something that we cannot explain in genetic detail.

Those people were alleging the birds coming out of dinosaurs, and how
the feathers evolved. I had watched enough videos and photos about
fossils of feathers on some type of dinosaurs. But creationist had
made a fetish of the "how a scale of a dino become a feather". They want
a narrative at genetic level we cannot provide. Some fossils with
feathers are 120 millions old. I downloaded videos about the change
from dinosaurs to birds, but I had not finished watching. I was with
a cold yesterday and fever. I had not humor to watch all those videos.

But i am totally sure, this doc Kleinman is making a hoax with his
application of probabilities to evolution. The probabilities exist, and
I have a light knowledge on this. Nor very deep for I have not had a real
need to know this matter deeper. I had enough with a sallow level.

For complex questions, like in the case of evolution, it is not possible
to apply mathematics for we do not know really well how it works the
machinery of evolution. At least our knowledge is not enough to apply
mathematics. Then, he is a bogus scientist in regard to this.

Someone can try to apply maths to evolution, but my honest opinion is that
it does not make any sense.

Eri

[jillery]

There are many mechanisms which separate populations long for enough
to accumulate enough genetic differences to make their genomes
incompatible at the molecular, embryological, developmental level.

For example, you know about plate tectonics, which necessarily
physically separate populations into isolated groups. And you know
about random mutations and natural selection and adaptation and
genetic drift, which necessarily makes isolated populations' genomes
diverge over time. And you know that genomes sufficiently different
are necessarily incapable of controlling embryological development to
produce fertile offspring. A logical deduction of these combined
facts make speciation inevitable.

For purposes of accepting speciation, there's no need to provide a
genetically detailed explanation. Such demands are characteristic of
the pseudo-skepticism practiced by Fundamentalist anti-evolutionists.

>Those people were alleging the birds coming out of dinosaurs, and how
>the feathers evolved. I had watched enough videos and photos about
>fossils of feathers on some type of dinosaurs. But creationist had
>made a fetish of the "how a scale of a dino become a feather". They want
>a narrative at genetic level we cannot provide. Some fossils with
>feathers are 120 millions old. I downloaded videos about the change
>from dinosaurs to birds, but I had not finished watching. I was with
>a cold yesterday and fever. I had not humor to watch all those videos.
>
>But i am totally sure, this doc Kleinman is making a hoax with his
>application of probabilities to evolution. The probabilities exist, and
>I have a light knowledge on this. Nor very deep for I have not had a real
>need to know this matter deeper. I had enough with a sallow level.
>
>For complex questions, like in the case of evolution, it is not possible
>to apply mathematics for we do not know really well how it works the
>machinery of evolution. At least our knowledge is not enough to apply
>mathematics. Then, he is a bogus scientist in regard to this.
>
>Someone can try to apply maths to evolution, but my honest opinion is that
>it does not make any sense.
>
>Eri
>
>
>
>> --
>>
>>
>> ----Android NewsGroup Reader----
>> http://usenet.sinaapp.com/
>

--
This space is intentionally not blank.

[rsNorman]

eridanus <leopoldo...@gmail.com> Wrote in message:

There is a lot of science done on the evolution of feathers as
well as the origin of flight. It is even true that Peter Nyikos
and John Harshman can engage in a reasonably civil discussion
although with disagreement over the technical issues of that
topic on a different news group and doing it without all that
personal nastiness.

There can be serious problems learning simply from watching
videos. Many TV presentations about supposedly "scientific"
topics even from supposedly learned sources like public
television and National Geographic tend to make everything into
very controversial mysteries with a lot of hype. All that
accompanied by usually extremely beautiful graphics that often
don't at all explain what is going on or even being too relevant.
When it is over you have a really pretty story that didn't
really say very much of content. On the other hand, the
scientific work is, as you probably full well know, highly
technical and specialized, not to mention extremely boring and
tedious to read.

Kleinman does have a point but his entire interest in in
pathological situations where some invasive agent -- virus,
bacterium, parasite, even an invasive weed -- is capable of
phenomenal exponential growth to enormous number capable of
entirely destroying the host environment. It needs quick and
total eradication to cure the problem. His mathematics may well
describe such a situation but it simply is not the way almost all
of biological evolution works.

And the technical subject called population genetics is a highly
mathematical development and understanding and correctly applying
those results have been crucial to the development of the
biological theory of evolution. Ecology and physiology are other
examples of biology that can be developed using relatively
advanced mathematical models. You don't use mathematics to study
the evolution of feathers. You do use mathematics to understand
how fast different types of genetic changes can occur and
propagate within populations.

[rsNorman]

rsNorman <r_s_n...@comcast.net> Wrote in message:

There are two things I forgot to include here.

Jillery already covered the first, speciation. I could only add
that, although tectonic drift provides many truly spectacular
examples of biogeographical speciation, it need not be that
extreme. Both Darwin and Wallace were drawn to evolution through
noting the distinctly different yet related species on isolated
islands. There are many other ways that a population of one
species can be divided into very distinct and separate
geographical areas.

Second, I should add that mathematical and computer science
methods are extremely important in analyzing the enormous masses
of genomic data to produce phonograph showing how evolution has
proceeded.


--

[John Harshman]

"Phonograph"? I suspect autocorrect.

[eridanus]

I agree; but not only plate tectonics. Just figure the meteorite of
Alvarez, for the sake of the argument, it could had caused large expanses
of land desert, for diverse reasons. The main one drought. The main reason
for drought I presume would had been the cooling of the ocean, after the
crash of the meteorite, or the Deccan volcanoes in India.
But in a few places there should had existed some havens where life
was possible, if precarious. In those islands of life, it would had been
probably a ground for diversification of surviving species. Specially for
those that were small in size and do no required much food.
Where those places should had been? Near the sea and around the equator.
SST would had been a little higher in places, and it were possible some
rains, near shore. At higher latitudes all was barren. Just an speculation
of an amateur.

Eri

[eridanus]

I am on guard with the videos. Sometimes it looks I hear some silly
things. I am not a passive listener or reader. I am trying to refute
or to resist what I read or hear.

On the other hand I would be pleased if these mathematics applied to the
theory of evolution are good enough. But as I am not an expert on this field
and have little interest in it, I would not take the effort to it. I only
pretend to have a light idea of science.
eri

[eridanus]

no problem. This concept is elemental.
What I am not so sure, is in the question of the computers.
eri

[rsNorman]

John Harshman <jhar...@pacbell.net> Wrote in message:

> On 10/26/16 11:13 AM, rsNorman wrote:
>> rsNorman <r_s_n...@comcast.net> Wrote in message:

>>

>> Second, I should add that mathematical and computer science
>> methods are extremely important in analyzing the enormous masses
>> of genomic data to produce phonograph showing how evolution has
>> proceeded.
>
> "Phonograph"? I suspect autocorrect.
>
>

It was a stereo phonograph so it sounded good to me.

My tablet is far superior to my cell phone and has pretty much
replaced my real computer. Typing with a Bluetooth keyboard
makes things very simple. Still I can't control the autocorrect.
It shows being turned off in the settings screen. It is very
annoying as is the signature ad which cannot be eliminated unless
you pay for the app. And it is not an app worth
money.

[jillery]

On Wed, 26 Oct 2016 14:13:41 -0400 (EDT), rsNorman
<r_s_n...@comcast.net> wrote:

> There are two things I forgot to include here.
>
>Jillery already covered the first, speciation. I could only add
> that, although tectonic drift provides many truly spectacular
> examples of biogeographical speciation, it need not be that
> extreme. Both Darwin and Wallace were drawn to evolution through
> noting the distinctly different yet related species on isolated
> islands. There are many other ways that a population of one
> species can be divided into very distinct and separate
> geographical areas.
>
>Second, I should add that mathematical and computer science
> methods are extremely important in analyzing the enormous masses
> of genomic data to produce phonograph showing how evolution has
> proceeded.

I assume "phonograph" is an over-anxious autocorrector, but I can't
help but wonder what the actual word should have been. I am tempted
to say something about trying more modern media, like floppy disks.

[jillery]

On Wed, 26 Oct 2016 11:33:02 -0700 (PDT), eridanus

As I said, plate tectonics is but one example of a variety of ways
populations can and do have reproductive isolation imposed on them. I
specifically chose that one as an example you recognize.

[rsNorman]

jillery <69jp...@gmail.com> Wrote in message:

Phenogram. But getting that word unchanged just now took a bit of
work.

[John Harshman]

I think you may have meant cladogram or phylogram.

[rsNorman]

John Harshman <jhar...@pacbell.net> Wrote in message:

Yes, absolutely. Those are exactly the words I meant.
Unfortunately that is not the word I wrote. Remember, I am just
a physiologist and don't appreciate the fine details about all
that even though I do have a published phenogram (yes, this time
I mean it). It was on based on the stomach structure of decapod
crustacea.

[John Harshman]

Dang it, now you have me thinking about a crawfish po'boy.

[erik simpson]

Must be another attack of the autocorrector. You meant, of course,
"crawdad". Good with hush puppies.

[*Hemidactylus*]

Vinyl is making a comeback. Is rnorman a dj like Moby? He could produce an
audio rendition of the evolutionary process with the help of an
interpretative dancer 😜🎼

[rsNorman]

*Hemidactylus* <ecph...@allspamis.invalid> Wrote in message:

> interpretative dancer ????
>
>

I actually did make a magnificent audio recording of my favorite
interpretive dancer performing to a purely imagined but
beautifully expressed ballet score. It was very subtle: the only
sound you could hear was the gentle swish of her discarded
clothing hitting the floor. Fifteen minutes of absolute beauty.
It didn't go over on utube at all.

[*Hemidactylus*]

eridanus <leopoldo...@gmail.com> wrote:
> How Reptiles Evolved to Form Humans Full Documentary

First off that's misleading. Humans and the organisms known colloquially as
"reptiles" are nested within the proper grouping of amniotes. The
distinguishing feature of amniotes is the cleidoic egg. Think of the eggs
you might cook for breakfast every day. The hard shell and other features
of this revolutionary egg helped this subset of land vertebrates become
less dependent upon waterways. Amphibians can make a decent living upon
land unlike "fishes" but are still quite dependent upon waterways. The
cleidoic egg is a portable contained waterway. Funny thing is that humans
have dead yolking genes and what can be construed as a yolk sac as embryos
which betray our deep ancestry as inner reptiles. Not quite McLean's
reptile brain though.

And a subset of "reptiles" called synapsids gave rise eventually to mammals
which eventually subsetted into apes including us. I think Shubin had a
separate episode called "Your Inner Monkey"

> https://www.youtube.com/watch?v=ShxoM5ujw1k
>
> here is a part on min 35 that starts something interesting about
> how the skin cells have some variations, that produce nails, teeth,
> sweat glands, hair, etc. Around this part, it presents a man that
> suffers from a rare mutation that do not have nails, or barely in a few
> of his finger. He had only a few teeth that had to be taken away for it
> was causing him problems. He had not any hair on his body of sweat
> glands. All these elements are some variety of skin cells, that for
> whatever reason do not worked.

All three episodes of Neil Shubin's documentary series should be viewed.
His book _Your Inner Fish_ is older but still quite good. He discovered
this critter:

https://en.m.wikipedia.org/wiki/Tiktaalik

> Then, talking about other subject, I remember a very sportive girl,
> that was very good running, and won some races. She got a boy and married.
> They got worried because she could not get pregnant. After a number of
> analysis it resulted that his sexual chromosomes were XY. The doc said
> that even in she had all the appearance of a woman, he was really a man
> and had testicles in the place of ovaries. But other wise she had all
> the external appearances of being a female. I observed in the video
> that the face of this girl look like she had too much testosterone, not
> only by the power of his jaw, but also in general she has a strong body
> like she were a male athlete.
> So, when we talk about genes, several different genes can be altered
> and it occur this sort of phenomenon. Some of the mutations are not
> helping the person, even if they are not lethal. A bad mutation in some
> part and something can get wrong. This looks like the argument of the
> creationist arguing about the scarce probabilities of something good
> to occur. This is false. So far as mutations do not alter some
> important genes everything goes according to some well known formula.

Many if not most mutations have negligible effects on survival and
reproduction outlooks. The negative connotations of mutation are greatly
hyperbolized, especially amongst creationists.

> The question that remains is to prove how a well functioning organism
> can change so much as to be "a little bit different". This is the way
> I suppose evolution works with mutations.

Gene duplication and divergence is an important mode. Screw ups during
formation of sex cells can result in two copies of a genes allowing the
second freedom to diverge from point mutations. Reiterations of this result
in gene families such as the Hox genes that underlie important deep
structural commonalities across bilaterians such as humans and flies.

> The change must be almost
> compatible with the general plan of the species. A few changes are
> possible if they are not altering the general plan.

The general plan or Archetype is fairly consistent across subgroups nested
within a larger group. That's why you see notochords and gill arches in
vertebrate embryos including us.

> By changing in
> little steps, they can accumulate some serious amount of differences
> after a time. How long a time? This is a problem, I think, we have
> had not yet solved.

Pick up a book on evolution. Not every detail of phylogeny (relations
between known organisms) is fully resolved but people know far more than
decades ago.

> Anyway, the video have some interesting points, easy to watch and to
> understand.
> There is also the problem not yet solved, I suppose is not yet solved,
> about when occur most or the changes in the genome of living organisms.

Much of the genome is unrelated to what we see as the structural features
of organisms. The genome projects have helped increase understanding as to
how many actual genes and regulatory regions there are and work has been
done to relate these things to phenotypes but much of the genome of various
organisms has no function for them and if not some parasitic or benign
hitchhiking retroviral element is just some extraneous garbage.

> If we believe the fragmentary fossil record, most of the proliferation
> of new species had occurred after some periods of serious extinctions.
> It is this a necessary condition?

Mass extinctions get rid of the underperforming dead weight and open up
niches or previously closed ways of life to enterprising new breeds. Or
some bolide slams the Earth and effectively hits the reset button.

> Or can this happen in all periods of
> time, far away from the moments of extinctions? Well, perhaps Ron can
> tell us. He seems to be the guru of evolution here.

In the rough and tumble between extinction events various things can happen
such as an errant group of organisms finding themselves on a remote island
free from predators and competitors where they can then diverge into
subgroups specialized to various open lifeways.

[rsNorman]

*Hemidactylus* <ecph...@allspamis.invalid> Wrote in message:

> eridanus <leopoldo...@gmail.com> wrote:
>> How Reptiles Evolved to Form Humans Full Documentary
>
> First off that's misleading. Humans and the organisms known colloquially as
> "reptiles" are nested within the proper grouping of amniotes. The
> distinguishing feature of amniotes is the cleidoic egg. Think of the eggs
> you might cook for breakfast every day. The hard shell and other features
> of this revolutionary egg helped this subset of land vertebrates become
> less dependent upon waterways. Amphibians can make a decent living upon
> land unlike "fishes" but are still quite dependent upon waterways. The
> cleidoic egg is a portable contained waterway. Funny thing is that humans
> have dead yolking genes and what can be construed as a yolk sac as embryos
> which betray our deep ancestry as inner reptiles. Not quite McLean's
> reptile brain though.

I snipped the rest, all good stuff, to comment about the cleidoic
egg. It is not the hard shell that matters. Most amniotic have
leathery shells. It is not the yolk sac. Fish and amphibians
have perfectly good yolk sacs. What really counts are the
extra-embryonic membranes of the amnion, chorion, and allantois.
That first is why we amnioties are called that. It surrounds the
embryo so it lives in a watery environment, the amniotic fluid.
That plus the waterproofing offered by the surrounded chorion let
the egg live a terrestrial life. The water permeable eggs of
fish and amphibians must be laid in water and held in some wet or
moist environment constantly during embryonic development.
Cleidoic eggs can be laid in land. That change was as essential
as air breathing to the transition from aquatic to terrestrial
life. Well, another factor was internal fertilization which
provided a means for the sperm to swim to the egg through a
watery environment.

[*Hemidactylus*]

Thanks for the clarifications. I recalled the importance of this egg but
kinda bungled the specifics.

[rsNorman]

Oops, another "essential" ingredient in the transition to
terrestrial life was a waterproof integument or skin. I should
have been able to just rattle off the list because I would make
students do that on exams along with specific examples each taken
from a different tetrapod class (back when there were amphibia,
reptiles, birds, and mammals). A strong skeleton capable of
supporting the weight of the body against gravity is also
important.

I guess the good Dr Dr was right after all: you can't make the
transition from aquatic to terrestrial without all those
properties and the law of multiplication of probabilities shows
that you cannot evolve adaptations to simultaneous selection
pressures. Excuse me, I am drying out so I have to return to my
nice warm salty tub. I am hoping to be able to get out after
reading Neil Shubin's "Your Inner Fish", something mentioned here
already several times.

[*Hemidactylus*]

I could hear you better if my jaw structure properly transitioned to become
ear ossicles. I am still as a gecko at the articular-quadrate stage. And
my species exhibits a known form of virgin birth though that's not
exclusively reptilian and it undercuts the patriarchy. Let's see humans do
*that*. Oh wait can we mistranslate almah?

But don't stay in the tub too long as your integument will prune, unless
you're one of those aquatic apes.

[eridanus]

i have not any basic problems with evolution. What we know is about the
evident aspects of changing and relations diverse organism have with other.
This is as well shown in fossils, even if we have not a complete picture.

But we lack a real knowledge of underground explanation of changes. All we
know are light ideas about what happened and how it occurred. But I cannot
blame scientists for not knowing, as this is quite an unreachable problem.

As for me to read thick books about evolution it would be a good advice if
I would had serious doubts about evolution. On the other hand, at my age,
79 years, it is a miracle I can maintain my interest for this light ideas
on science. Specially if you consider that I made only the grammar school.
I began to read books around my 30 years of age, that I was earning a little
more money. It was a very slow process anyway. You cannot pass from being
nearly and ignorant to become a learned person. This process takes a number
of decades. In the next 30 or 40 years I would be more intelligent, but probably I would never outlive another decade over the present time.

So, I am not in any hurry in my quest of a higher intelligence. I am just
enjoying the time commenting and reading some arguments.

eri

[Oxyaena]

On 10/25/2016 1:20 PM, eridanus wrote:
> How Reptiles Evolved to Form Humans Full Documentary

> https://www.youtube.com/watch?v=ShxoM5ujw1k
>
> here is a part on min 35 that starts something interesting about
> how the skin cells have some variations, that produce nails, teeth,
> sweat glands, hair, etc. Around this part, it presents a man that
> suffers from a rare mutation that do not have nails, or barely in a few
> of his finger. He had only a few teeth that had to be taken away for it
> was causing him problems. He had not any hair on his body of sweat
> glands. All these elements are some variety of skin cells, that for
> whatever reason do not worked.
>
>

> Then, talking about other subject, I remember a very sportive girl,
> that was very good running, and won some races. She got a boy and married.
> They got worried because she could not get pregnant. After a number of
> analysis it resulted that his sexual chromosomes were XY. The doc said
> that even in she had all the appearance of a woman, he was really a man
> and had testicles in the place of ovaries. But other wise she had all
> the external appearances of being a female. I observed in the video
> that the face of this girl look like she had too much testosterone, not
> only by the power of his jaw, but also in general she has a strong body
> like she were a male athlete.
> So, when we talk about genes, several different genes can be altered
> and it occur this sort of phenomenon. Some of the mutations are not
> helping the person, even if they are not lethal. A bad mutation in some
> part and something can get wrong. This looks like the argument of the
> creationist arguing about the scarce probabilities of something good
> to occur. This is false. So far as mutations do not alter some
> important genes everything goes according to some well known formula.
>

> The question that remains is to prove how a well functioning organism
> can change so much as to be "a little bit different". This is the way

> I suppose evolution works with mutations. The change must be almost

> compatible with the general plan of the species. A few changes are

> possible if they are not altering the general plan. By changing in

> little steps, they can accumulate some serious amount of differences
> after a time. How long a time? This is a problem, I think, we have
> had not yet solved.

> Anyway, the video have some interesting points, easy to watch and to
> understand.
> There is also the problem not yet solved, I suppose is not yet solved,
> about when occur most or the changes in the genome of living organisms.
>

> If we believe the fragmentary fossil record, most of the proliferation
> of new species had occurred after some periods of serious extinctions.

> It is this a necessary condition? Or can this happen in all periods of

> time, far away from the moments of extinctions? Well, perhaps Ron can
> tell us. He seems to be the guru of evolution here.
>

> Eri
>
>
>
>
I have a small problem with the title of your OP, mammals evolved from
synapsids (and are still synapsids), not sauropsids such as birds and
reptiles. There are many tantalizing pieces of evidence from the fossil
record of the gradual transition of therapsids into mammals, in fact,
one cynodont has both a reptilian jaw joint and mammalian jaw joint, in
other species you can see a gradual expansion of the dentary at the
expense of the other jaw bones, which in turn form two of the three
middle ear bones.


Other features include the evolution of a secondary palate, a
differentiation of the teeth (heterodonty, a characteristic of all
synapsids, with the earliest synapsid, *Archaeothryis*, possessing two
canines while the rest of the teeth were basic reptilian set,
*Dimetrodon* possessing incisors and canines, and I`m sure you get the
point), as well as a gradual erection of the limbs, most therapsids
aside from Dicynodonts possessed erect forelimbs and sprawling
side-limbs, while cynodonts and mammals possess fully erect limbs).

--
http://oxyaena.org/

[eridanus]

I had not memorized the details of those questions of evolution for I do not
pretend to pass an examination. On the other hand I barely had a memory for these weird names of diverse classes of dinosaurs.

This argument you present looks like splitting hairs to me. Anything I read
or heard in a video, I am sure that can be wrong. It is a fix idea I have.
For most of these questions about clades are not 100% sure in some of its
parts, and exist some rational disagreements. I cannot care for disagreements,
among experts. Science is not the word of god. Even it were the words of
god, you know that exist the schisms and the heresies. Even the words of
god... which god? For there are some assorted fake gods as well.

I takes science as a narrative that is changing and improving with time.
Why it is improving? Because it can be erased parts that younger generation
of scientists decide they were wrong.

When I watched a video, some questions are pleasant to me. I have in this
moment no reasons to doubt of what some speaker is saying. But on occasions
I feel some saying is wrong. I guide myself by feelings. Some arguments
made me feel right, some arguments make me not. Of course my feelings can be
worthless to others. But this often happens among scientists as well. I
cannot worry by this minutia.

eri

[Otangelo Grasso]

> How Reptiles Evolved to Form Humans Full Documentary

They didnt.

[eridanus]

El lunes, 31 de octubre de 2016, 3:00:03 (UTC), Otangelo Grasso escribió:
> > How Reptiles Evolved to Form Humans Full Documentary
>
> They didnt.

do you think is unbelievable the theory of evolution? A lot more unbelievable
is think a supernatural being was alone for a time infinite and suddenly
decided to make this huge universe of 100 trillion galaxies or more. What
need had a god of creating the universe? Do god needed to create humans and
demons and angels? I prefer to believe in the theory of evolution. It looks
more logical, and we have a hope of understanding every riddle of it, in due
time.

eri