Green Camouflage Question ...
Cyde Weys
was looking out my window today, and seeing all of the crows (black),
squirrels (grey) and other birds (brown) was painfully easy on my GREEN
grass and GREEN trees. As far as I know, it's only animals like frogs and
lizards that have evolved green camouflage. Why not some other creature?
It seems terribly useful to me!
RHertz
"Cyde Weys" <vze2...@verizon.net> wrote in message
news:x4kT8.6850$vr5....@nwrddc01.gnilink.net...
Unless you're trying to MATE with one of them critters. In that case,
camouflage isn't going to be helpful.
One doesn't go into a singles bar wearing clothes that match the paneling so
one can disappear. Many, many animals go out of their way to be *visible*.
Consider the peacock. All in the name of sex.
Note that the males of the species are often the more visible ones. The
females tend to be duller in color. Why? Because, generally speaking, the
females are the ones that must nuture the offspring. Now camo becomes an
advantage. The only purpose of the male is to live long enough to mate.
After that, he can be eaten by predators and no one will miss him.
Cyde Weys
"RHertz" <RHer...@cox.rr.com> wrote in message
news:3xkT8.10821$GF4.5...@twister.southeast.rr.com...
This still doesn't explain why the females of the species don't have green
camouflaging.
Kleuskes & Moos
> This still doesn't explain why the females of the species don't have green
> camouflaging.
The best way to camouflage is assuming da dark color and to disappear into
the shadows. Having a green camouflage colour is _only_ effective at
daytime.
Then there are other reasons:
* many, if not most predators are active during the night
* many, if not most predators rely on sense of smell and/or hearing instead
of sight to seek out prey . Having a camouflage colour simply won't help.
* if you hide between the greenery onstead of on top of it camouflage is
not very usefull
* in many cases camouflage is not as effective as flight or fight.
* The stems of trees are usually not green, but brownish grey.
* many animals use colors or colored patches as signals (rabbit's tale).
Camouflage _only_ makes sense if you can not outrun or outfight the
predator or are, for some reason immobile. a calf of a deer is an exellent
example. Virtually no smell and a brownish spotted coat in order to vanish
into the forest floor.
Grey, by the way, is an excellent camouflage colour at night. As is black,
tan, especially if it's mottled.
Regards,
Kleuske.
Adam Marczyk
Actually, I read an article about this not long ago (in the New York Science
Times, I think) that said this picture was somewhat oversimplified; in many
species females compete to attract males as well. It depends mainly on sex
ratios and how much care the male parent puts into raising the offspring.
--
And I want to conquer the world,
give all the idiots a brand new religion,
put an end to poverty, uncleanliness and toil,
promote equality in all of my decisions...
--Bad Religion, "I Want to Conquer the World"
http://www.ebonmusings.org ICQ: 8777843 PGP Key ID: 0x5C66F737
Nathan Urban
> Just a musing: why haven't more animals evolved green camouflaging? I
> was looking out my window today, and seeing all of the crows (black),
> squirrels (grey) and other birds (brown) was painfully easy on my GREEN
> grass and GREEN trees.
Hmm. Just yesterday, I was noticing how superbly the gray-and-brown
squirrels blend in with the dirt, wood chips, and fallen branches
underneath the trees. If they weren't moving, and I weren't looking
directly at them, I doubt I'd have noticed them. In the trees,
they're not that easy to see either, just from the amount of foliage
and shadows. Of course, they are visible on the grass.
But anyway, I wonder how easy it is for a mutation to produce green
fur on a mammal, as opposed to green skin on a reptile.
Mark VandeWettering
Other predators don't have the same color sensitivity that you do.
Camouflage from predators may also be camouflage against mates.
--
"The fundamentalists, by 'knowing' the answers before they start
(examining evolution), and then forcing nature into their straitjacket
of their discredited preconceptions, lie outside the domain of
science--or of any honest intellectual inquiry." -- S. J. Gould
Patrick James
(in message <IDkT8.7120$vr5....@nwrddc01.gnilink.net>):
A lot of birds _do_ have considerable sex-based differences in plumage. Birds
of paradise. Some ducks. Some hummingbirds. (Male doctorbirds are very bright
mettalic green and black, with long tail feathers; females are drab
olive-and-tan, with short tail feathers) Some other birds tend to have lots
of colour _on parts of the body not usually visible when at rest_; the local
ground doves, for instance, are grey-brown on most of the body, but have
white and red feathers in their wings... and those parts of their wings are
folded up where they can't be seen when the dove is on the ground. Lots of
small mammals tend to be brown or tan or some such earth-like colour. Arctic
mammals tend to be white. Some northern temparate zone mammals change colour
depending on the time of year, from brown/tan to white. An awful lot of
mid-size and small raptors (many owls and falcons, for example) are brownish
or greyish above, and some light colour below, making it hard for them to be
seen from above (against the ground) or below (against the sky.) Gulls are
notoriously white below and darkish above, for the same reason. (_Large_
raptors, like eagles and larger vultures, don't give a damn who sees them.
They're the baddest boyz'n'grrlz on wings, and they know it. Frigate birds
have the same attitude, and for the same reason.)
Some mammals _are_ greenish-brown: the Indian mongoose, for instance, ranges
in colour from grey to brown to kind of an olive greenish brown. This does
not help 'em much against the #1 killer of mongooses around here: the
motorcar. (HM Gov brought mongooses to the Caribbean to get rid of snakes.
Someone forgot that mongooses also eat eggs, and it's a lot easier to get at
ground dove nests or chicken coops than to go chasing vipers or boas. Not to
mention that there aren't any cobras around here, and vipers are smarter than
cobras, or at least better optimised for hunting small mammals. oops.)
Lions are tan... the colour of not-very-well-watered grass. This works well
enough for 'em to get close enough to their prey for that last sprint.
And camouflage can work without being green. See further zebras, tigers,
leopards... Break up that outline! Lion cubs are spotted, like leopards;
hyenas have spots _and_ stripes.
--
Si hoc legere scis nimium eruditionis habes
TomS
<afkoao$ah5$1...@crib.corepower.com>, nur...@crib.corepower.com stated..."
Are there any mammals with green colored fur? Or, red or blue?
(Not counting reddish-brown as red.)
It is conceivable that there is something to the chemistry
that doesn't allow any color of fur other than black, white and
brown.
Tom S.
Patrick James
(in message <afkoao$ah5$1...@crib.corepower.com>):
> In article <x4kT8.6850$vr5....@nwrddc01.gnilink.net>, "Cyde Weys"
> <vze2...@verizon.net> wrote:
>
>> Just a musing: why haven't more animals evolved green camouflaging? I
>> was looking out my window today, and seeing all of the crows (black),
>> squirrels (grey) and other birds (brown) was painfully easy on my GREEN
>> grass and GREEN trees.
>
> Hmm. Just yesterday, I was noticing how superbly the gray-and-brown
> squirrels blend in with the dirt, wood chips, and fallen branches
> underneath the trees. If they weren't moving, and I weren't looking
> directly at them, I doubt I'd have noticed them. In the trees,
> they're not that easy to see either, just from the amount of foliage
> and shadows. Of course, they are visible on the grass.
Lots of small mammals which live (mostly) on the ground are grey or tan or
brown. The list of brown or grey rodents alone is quite long: rats,
chipmunks, squirrels, beavers...
>
> But anyway, I wonder how easy it is for a mutation to produce green
> fur on a mammal, as opposed to green skin on a reptile.
>
It can be done, but not a leaf-like green, more of a brownish green or a
greyish green. And there are a lot of tans.
Stacy Lynn
<ebon...@hotmailNOTexcite.com> wrote:
>Actually, I read an article about this not long ago (in the New York Science
>Times, I think) that said this picture was somewhat oversimplified; in many
>species females compete to attract males as well. It depends mainly on sex
>ratios and how much care the male parent puts into raising the offspring.
For example, most parrots are not sexually dimorphic, and the few that
are usually only differ slightly. Except for Ecletus which the male
is red and the female is green (or vice versa, I cannot remember).
Otherwise, sexual dimorphism in parrots is usually limited to things
like male pacific parrotlets having a bit of blue on their rump, or
male cockatiels having a yellow face. Parrots pair bond and mate for
life, both parrots having an active part in raising the chicks.
Stacy
Lane Lewis
helps in the camouflage department.
Lane
A bachelor's fridge: home of the Chia-Meatloaf.
Lane Lewis
Once you get into the forest the the ground and the trees are not green.
Also many animals are colorblind. We had these little so called chameleons
(anole?) in florida that when on a leaf it would turn bright green and when
on a limb would turn dark brown, it was probably colorblind but changed due
to the temperture difference.
Lane
Mike Dunford
news:01HW.B94357E80...@enews.newsguy.com:
[snip]
> Some mammals _are_ greenish-brown: the Indian mongoose, for
> instance, ranges in colour from grey to brown to kind of an
> olive greenish brown. This does not help 'em much against the #1
> killer of mongooses around here: the motorcar. (HM Gov brought
> mongooses to the Caribbean to get rid of snakes. Someone forgot
> that mongooses also eat eggs, and it's a lot easier to get at
> ground dove nests or chicken coops than to go chasing vipers or
> boas. Not to mention that there aren't any cobras around here,
> and vipers are smarter than cobras, or at least better optimised
> for hunting small mammals. oops.)
There are similar issues with the mongoose out here in Hawaii. They
were originally imported here in an effort to control the rapidly
expanding population of rats which had arrived on ships. Only problem
with that bright idea was that the mongoose is most active during the
day, while the rat...
> Lions are tan... the colour of not-very-well-watered grass. This
> works well enough for 'em to get close enough to their prey for
> that last sprint.
Back to the original point of the thread, it is probably more useful
to be the color of not well watered grass if you are a mammal anyway.
Well-watered, close-cropped lawns are not the most common of natural
environments.
[snip]
--Mike Dunford
--
It might not be much of a life in our terms, but it keeps several
species of anglerfish going... And who can judge anyway? In some
ultimate Freudian sense, what male could resist the fantasy of life
as a penis with a heart...
--Stephen Jay Gould
Dick C
I know others have said similar things to what I am going to say,
but consider what predators prey on the animals in question, and
how they protect themselves. Squirrels are preyed upon by cats and
dogs, but they are able to see them coming usually and can run away
from them. They are also preyed upon by large birds from the air.
These birds are harder to spot, and if the raptor sees the squirrel
it will attack silently and swiftly. And the squirrel would not stand
a chance. The grey coloring of the squirrel is an excellent coloring
for protection.
I was looking at a tree today, from above. A branch was shaking and
moving, but I could not see what was causing it until a squirrel
climbed on top to jump to another branch. Inspite of not being
green the squirrel was all but invisible from above.
--
Dick #1349
"Believe those who are seeking the truth; doubt those who find it."
Andre Gide, French author and critic (1869-1951).
email: crav...@msn.net
Stephen Poley
Well they have - you just failed to see them. ;-)
Quite a lot of warblers (family Sylvidae) are greenish in colour,
especially the genus Phylloscopus. Similarly many of the new-world
flycatchers (Tyrannidae), hummingbirds, finches and parrots, to name a
few.
Don't forget though that in temperate latitudes there aren't many green
leaves around for half the year. Browns and greys are likely to be more
effective in winter (except in those areas with guaranteed snow cover)
and are still pretty good in the summer.
HTH
Stephen Poley
Barendrecht, Holland
Cyde Weys
"Mike Dunford" <mdun...@hawaii.rr.com> wrote in message
news:Xns923C59DCF5...@66.75.162.198...
> Patrick James <patj...@newsguy.com> wrote in
> news:01HW.B94357E80...@enews.newsguy.com:
>
> [snip]
> > Some mammals _are_ greenish-brown: the Indian mongoose, for
> > instance, ranges in colour from grey to brown to kind of an
> > olive greenish brown. This does not help 'em much against the #1
> > killer of mongooses around here: the motorcar. (HM Gov brought
> > mongooses to the Caribbean to get rid of snakes. Someone forgot
> > that mongooses also eat eggs, and it's a lot easier to get at
> > ground dove nests or chicken coops than to go chasing vipers or
> > boas. Not to mention that there aren't any cobras around here,
> > and vipers are smarter than cobras, or at least better optimised
> > for hunting small mammals. oops.)
>
> There are similar issues with the mongoose out here in Hawaii. They
> were originally imported here in an effort to control the rapidly
> expanding population of rats which had arrived on ships. Only problem
> with that bright idea was that the mongoose is most active during the
> day, while the rat...
So what happened with the mongooses?
> > Lions are tan... the colour of not-very-well-watered grass. This
> > works well enough for 'em to get close enough to their prey for
> > that last sprint.
>
> Back to the original point of the thread, it is probably more useful
> to be the color of not well watered grass if you are a mammal anyway.
> Well-watered, close-cropped lawns are not the most common of natural
> environments.
So in nature most grass is dying, not thriving??
Cyde Weys
"Kleuskes & Moos" <some...@over.the.rainbow> wrote in message
news:afkns2$2k5a$1...@scavenger.euro.net...
> Cyde Weys wrote:
>
> > This still doesn't explain why the females of the species don't have
green
> > camouflaging.
>
> The best way to camouflage is assuming da dark color and to disappear into
> the shadows. Having a green camouflage colour is _only_ effective at
> daytime.
>
> Then there are other reasons:
>
> * many, if not most predators are active during the night
I disagree. Not "most" predators ... some.
> * many, if not most predators rely on sense of smell and/or hearing
instead
> of sight to seek out prey . Having a camouflage colour simply won't
help.
Many predators using sight. If a lion is chasing down a zebra, what do you
think is going to help more in that last 100 feet, being able to smell that
there's a zebra there, or being able to see it and go directly at it?
Cyde Weys
"Patrick James" <patj...@newsguy.com> wrote in message
news:01HW.B9435A160...@enews.newsguy.com...
> On Sat, 29 Jun 2002 11:43:49 -0500, Nathan Urban wrote
> (in message <afkoao$ah5$1...@crib.corepower.com>):
>
> > In article <x4kT8.6850$vr5....@nwrddc01.gnilink.net>, "Cyde Weys"
> > <vze2...@verizon.net> wrote:
> >
> >> Just a musing: why haven't more animals evolved green camouflaging? I
> >> was looking out my window today, and seeing all of the crows (black),
> >> squirrels (grey) and other birds (brown) was painfully easy on my GREEN
> >> grass and GREEN trees.
> >
> > Hmm. Just yesterday, I was noticing how superbly the gray-and-brown
> > squirrels blend in with the dirt, wood chips, and fallen branches
> > underneath the trees. If they weren't moving, and I weren't looking
> > directly at them, I doubt I'd have noticed them. In the trees,
> > they're not that easy to see either, just from the amount of foliage
> > and shadows. Of course, they are visible on the grass.
>
> Lots of small mammals which live (mostly) on the ground are grey or tan or
> brown. The list of brown or grey rodents alone is quite long: rats,
> chipmunks, squirrels, beavers...
I hope you didn't just allege that a beaver is a rodent ...
Cyde Weys
"Lane Lewis" <myn...@hotmail.com> wrote in message
news:cjmT8.1173$6Y3...@nwrddc04.gnilink.net...
> The sloth grows mold on its fur and turns a shade of green. Not sure if it
> helps in the camouflage department.
I can imagine a symbiotic relationship whereby photosynthetic mold makes an
animal green to hide in the grass, and as a response, this animal will
actively seek out sunlight, giving the mold more light than it could ever
have if it stayed still.
R. Baldwin
news:x4kT8.6850$vr5....@nwrddc01.gnilink.net...
You only think the trees are green. Actually, there is far more red
content than green in the broad spectrum of sunlight reflected by
chlorophyll. The reason you see it as green is that the human eye has
a stronger response to green than read.
I don't know this, but suspect more critters have evolved camoflaging,
but to match the visual acuity of their predators rather than the
visual acuity of Homo sapiens.
Patrick James
(in message <sYoT8.9343$vr5....@nwrddc01.gnilink.net>):
Lions see very, very, very well at night.
Patrick James
(in message <zXoT8.9341$vr5....@nwrddc01.gnilink.net>):
>
> "Mike Dunford" <mdun...@hawaii.rr.com> wrote in message
> news:Xns923C59DCF5...@66.75.162.198...
>> Patrick James <patj...@newsguy.com> wrote in
>> news:01HW.B94357E80...@enews.newsguy.com:
>>
>> [snip]
>>> Some mammals _are_ greenish-brown: the Indian mongoose, for
>>> instance, ranges in colour from grey to brown to kind of an
>>> olive greenish brown. This does not help 'em much against the #1
>>> killer of mongooses around here: the motorcar. (HM Gov brought
>>> mongooses to the Caribbean to get rid of snakes. Someone forgot
>>> that mongooses also eat eggs, and it's a lot easier to get at
>>> ground dove nests or chicken coops than to go chasing vipers or
>>> boas. Not to mention that there aren't any cobras around here,
>>> and vipers are smarter than cobras, or at least better optimised
>>> for hunting small mammals. oops.)
>>
>> There are similar issues with the mongoose out here in Hawaii. They
>> were originally imported here in an effort to control the rapidly
>> expanding population of rats which had arrived on ships. Only problem
>> with that bright idea was that the mongoose is most active during the
>> day, while the rat...
>
> So what happened with the mongooses?
They eat chicken eggs instead. And chickens. And any other bird which nests
on or near the ground. They're _very_ good at it. See further
'Riki-Tikki-Tavi', Rudyard Kipling.
>
>>> Lions are tan... the colour of not-very-well-watered grass. This
>>> works well enough for 'em to get close enough to their prey for
>>> that last sprint.
>>
>> Back to the original point of the thread, it is probably more useful
>> to be the color of not well watered grass if you are a mammal anyway.
>> Well-watered, close-cropped lawns are not the most common of natural
>> environments.
>
> So in nature most grass is dying, not thriving??
>
A lot of the time the grass on major plains, such as the American paire, the
Serengeti, the southern African veldt, the Deccan, and the central Asian
steppe, is very dry. That's why grass and brush fires are so feared there.
Once they get started they're very hard to stop. See further Arizona, earlier
this week.
Patrick James
(in message <10pT8.9360$vr5....@nwrddc01.gnilink.net>):
It's not? Canadians think it is... Quote "the largest rodent in Canada" from
< http://www.pch.gc.ca/ceremonial-symb/english/emb_other_beaver.html>.
Rabbits ain't rodents, but beaver sure 'nuff are.
rossum
<TomS_...@newsguy.com> wrote:
[snip]
> Are there any mammals with green colored fur? Or, red or blue?
>(Not counting reddish-brown as red.)
>
[snip]
> Tom S.
>
Some humans have "red" hair which can be quite bright. Foxes are also
on the red side of reddish brown. Mandrills have bright colours, but
that is skin rather than hair.
rossum
Dick C
>
> "Mike Dunford" <mdun...@hawaii.rr.com> wrote in message
>> > Lions are tan... the colour of not-very-well-watered grass. This
>> > works well enough for 'em to get close enough to their prey for
>> > that last sprint.
>>
>> Back to the original point of the thread, it is probably more useful
>> to be the color of not well watered grass if you are a mammal anyway.
>> Well-watered, close-cropped lawns are not the most common of natural
>> environments.
>
> So in nature most grass is dying, not thriving??
In the wild grass only gets water when it rains. Which in most of
the grassland areas is mainly during the spring or fall. Sometimes only
during the spring. The rest of the year the grass is brown and dry.
The grass is still alive, taken over a year's period it is thriving.
Elmer Bataitis
> Just a musing: why haven't more animals evolved green camouflaging? I
> was looking out my window today, and seeing all of the crows (black),
> squirrels (grey) and other birds (brown) was painfully easy on my GREEN
> grass and GREEN trees. As far as I know, it's only animals like frogs and
> lizards that have evolved green camouflage. Why not some other creature?
> It seems terribly useful to me!
Ahhh, but, as expected, you aren't seeing the green ones ;-)
***************************************************************
Elmer Bataitis “Hot dog! Smooch city here I come!”
Planetech Services -Hobbes
585-442-2884
"...proudly wearing and displaying, as a badge of honor, the
straight jacket of conventional thought."
***************************************************************
Cyde Weys
As do lions' more ferocious cousins, Feline domesticus
Cyde Weys
"R. Baldwin" <res0k7y...@verizon.net> wrote in message
news:LJpT8.9567$vr5...@nwrddc01.gnilink.net...
> "Cyde Weys" <vze2...@verizon.net> wrote in message
> news:x4kT8.6850$vr5....@nwrddc01.gnilink.net...
> > Just a musing: why haven't more animals evolved green
> camouflaging? I
> > was looking out my window today, and seeing all of the crows
> (black),
> > squirrels (grey) and other birds (brown) was painfully easy on my
> GREEN
> > grass and GREEN trees. As far as I know, it's only animals like
> frogs and
> > lizards that have evolved green camouflage. Why not some other
> creature?
> > It seems terribly useful to me!
> >
>
> You only think the trees are green. Actually, there is far more red
> content than green in the broad spectrum of sunlight reflected by
> chlorophyll. The reason you see it as green is that the human eye has
> a stronger response to green than read.
This, quite blatantly, is NOT true. I've done experiments before using
optical sensors: they return R, G, and B components in an unbiased manner.
Chlorophyll reflects most at the 550nm rangle of the electromagnetic
spectrum. This is the part of the spectrum that is green in the optical
range.
No ifs, ands, or buts about it. Grass is GREEN because it is inherent in
the molecular chemistry of grass that it is green. Grass is green not
because we perceive it as such, but because it is. Were grass to reflect
highly in the 650nm range of the spectrum, THEN you could say it is green,
but alas, it is not.
Besides, where in the hell did you get this info that eyes perceive green
more strongly than red, anyway? As far as I know (which is quite a lot,
I've taken neurology courses ...), the eyes have rods (black/white) and
cones (red/green/blue). There is a 1:1:1 ratio of different cones in the
retina. It makes no sense that we should perceive one color as brighter
than another.
So, wherever your "source" is that leaves are really red, we just see the
green in them, I'd really like to see it. It's most likely BS.
HOWEVER: there is one important thing to note. Chlorophyll actually does
reflect somewhere in the spectrum more brightly than it does for 550nm.
Where? In the 750nm range. This is infrared radiation. Humans cannot see
it. It is not red, it is invisible. This is why plants need sun light, not
artificial fluorescent light. Sunlight has a LOT of infrared in it;
fluorescent, for the most part, is strong in the visual part of the
spectrum.
So, in a way, what you said is _sort_ of true ... grass does shine more
brightly in infrared than in green, and since humans cannot see infrared,
then it appears to be green to us. But infrared is not red ... it's
something totally different altogether. Imagine a hypothetical creature
that can see in the wavelengths 450 (blue) to 750 (infrared). What color
will chlorophyll appear to them? Green/infrared! In their eyes, it would
shine most brightly in the green and infrared parts of the spectrum. But
certainly not in the red part of the spectrum.
I rest my case.
Cyde Weys
"Elmer Bataitis" <nyli...@frontiernet.net> wrote in message
news:3D1E3911...@frontiernet.net...
> Cyde Weys wrote:
>
> > Just a musing: why haven't more animals evolved green camouflaging?
I
> > was looking out my window today, and seeing all of the crows (black),
> > squirrels (grey) and other birds (brown) was painfully easy on my GREEN
> > grass and GREEN trees. As far as I know, it's only animals like frogs
and
> > lizards that have evolved green camouflage. Why not some other
creature?
> > It seems terribly useful to me!
>
> Ahhh, but, as expected, you aren't seeing the green ones ;-)
That's a tautology.
Mike Dunford
> "Mike Dunford" <mdun...@hawaii.rr.com> wrote in message
> news:Xns923C59DCF5...@66.75.162.198...
>> Patrick James <patj...@newsguy.com> wrote in
>> news:01HW.B94357E80...@enews.newsguy.com:
>>
>> [snip]
>> > Some mammals _are_ greenish-brown: the Indian mongoose, for
>> > instance, ranges in colour from grey to brown to kind of an
>> > olive greenish brown. This does not help 'em much against the
>> > #1 killer of mongooses around here: the motorcar. (HM Gov
>> > brought mongooses to the Caribbean to get rid of snakes.
>> > Someone forgot that mongooses also eat eggs, and it's a lot
>> > easier to get at ground dove nests or chicken coops than to
>> > go chasing vipers or boas. Not to mention that there aren't
>> > any cobras around here, and vipers are smarter than cobras,
>> > or at least better optimised for hunting small mammals.
>> > oops.)
>>
>> There are similar issues with the mongoose out here in Hawaii.
>> They were originally imported here in an effort to control the
>> rapidly expanding population of rats which had arrived on
>> ships. Only problem with that bright idea was that the mongoose
>> is most active during the day, while the rat...
>
> So what happened with the mongooses?
I damn near hit one of them just now on my way back home from grocery
shopping. They didn't do much to supress the rat population (the
feral cats take care of that) but they are one of the reasons that
Hawaii has more endangered species than anywhere else in the US.
>> > Lions are tan... the colour of not-very-well-watered grass.
>> > This works well enough for 'em to get close enough to their
>> > prey for that last sprint.
>>
>> Back to the original point of the thread, it is probably more
>> useful to be the color of not well watered grass if you are a
>> mammal anyway. Well-watered, close-cropped lawns are not the
>> most common of natural environments.
>
> So in nature most grass is dying, not thriving??
I wouldn't say that it's dying, but it certainly isn't the deep, lush
green of most lawns either. For at least a large part of the year,
most of the large grasslands are more of a tan, or green-brown.
--Mike Dunford
--
They laughed at Columbus, they laughed at Fulton, they laughed at
the Wright Brothers. But they also laughed at Bozo the Clown.
--Carl Sagan
Richard S. Norman
> Just a musing: why haven't more animals evolved green camouflaging? I
>was looking out my window today, and seeing all of the crows (black),
>squirrels (grey) and other birds (brown) was painfully easy on my GREEN
>grass and GREEN trees. As far as I know, it's only animals like frogs and
>lizards that have evolved green camouflage. Why not some other creature?
>It seems terribly useful to me!
Have you ever seen a katydid or a grasshopper? Actually the Ecology
course on our campus regularly does a field experiment where the
students collect grasshoppers from different habitats -- brown and
green -- and count how many green vs brown specimens they find in each
environment.
The real question you must ask is whether the natural predators of
these animals have color vision! You also have to ask whether those
particular birds spend most of their time on leafy backgrounds or on
dark backgrounds. Remember that birds and squirrels tend to perch
on large branches which are distincly not green.
Richard S. Norman
<vze2...@verizon.net> wrote:
>
>"Patrick James" <patj...@newsguy.com> wrote in message
>news:01HW.B9435A160...@enews.newsguy.com...
>> On Sat, 29 Jun 2002 11:43:49 -0500, Nathan Urban wrote
>> (in message <afkoao$ah5$1...@crib.corepower.com>):
>>
>> > In article <x4kT8.6850$vr5....@nwrddc01.gnilink.net>, "Cyde Weys"
>> > <vze2...@verizon.net> wrote:
>> >
>> >> Just a musing: why haven't more animals evolved green camouflaging? I
>> >> was looking out my window today, and seeing all of the crows (black),
>> >> squirrels (grey) and other birds (brown) was painfully easy on my GREEN
>> >> grass and GREEN trees.
>> >
>> > Hmm. Just yesterday, I was noticing how superbly the gray-and-brown
>> > squirrels blend in with the dirt, wood chips, and fallen branches
>> > underneath the trees. If they weren't moving, and I weren't looking
>> > directly at them, I doubt I'd have noticed them. In the trees,
>> > they're not that easy to see either, just from the amount of foliage
>> > and shadows. Of course, they are visible on the grass.
>>
>> Lots of small mammals which live (mostly) on the ground are grey or tan or
>> brown. The list of brown or grey rodents alone is quite long: rats,
>> chipmunks, squirrels, beavers...
>
>I hope you didn't just allege that a beaver is a rodent ...
Are you suggesting that a beaver is not a rodent? Check out
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=Taxonomy
which specifies for beaver:
Eukaryota; Metazoa; Chordata; Craniata; Vertebrata;
Euteleostomi; Mammalia; Eutheria; Rodentia; Sciurognathi;
Castoridae; Castor
Greg
> Just a musing: why haven't more animals evolved green camouflaging? I
> was looking out my window today, and seeing all of the crows (black),
> squirrels (grey) and other birds (brown) was painfully easy on my GREEN
> lizards that have evolved green camouflage. Why not some other creature?
> It seems terribly useful to me!
I would say it's because Noah didn't take a lawn mower on the Ark.
After the Flood receded and the large cats were "adapting" into lions
and tigers and bears, there were no mowed lawns where green mammals
could evolve into the niche. Squirrels had to blend into the tree
trunks and leaf litter on the ground. Crows are diurnal so they are
most vulnerable at night. Besides, a green crow would be a parrot.
Another reason was given by Frank Sinatra in the song titled "It's Not
Easy Being Green." The song was covered by Kermit the Frog on Sesame
Street, too. IIRC, one of the lines of the song was "You blend in with
so many ordinary things."
Perhaps there was a species of eagle that preferred green squirrels
the way I like fried green tomatoes and made that allele extinct in
the squirrel population.
But seriously, go out into a natural setting, away from civilization,
and look at how many non-green animals you see, which will be few.
Then sit quietly for a while until they begin to forage again to see
how effective their camoflage really can be.
Plants that are all green tend to not be able to support the weight of
small mammals the way a nice brown or gray tree trunk can.
--
Greg
Let's do it right the furst time!
Tim Norfolk
>As far as I know, it's only animals like frogs and
>lizards that have evolved green camouflage. Why not some other creature?
There are several species of green parrot, and the potto has a symbiotic green
algae that lives in its fur.
Timsn274
"Just when we manage to idiot-proof something, Nature comes along and builds a
better idiot."
Tim Norfolk
>The only purpose of the male is to live long enough to mate.
>After that, he can be eaten by predators and no one will miss him.
>
Since I am now 45, and my wife had a baby on Tuesday, that is a very cheery
thought!
Stacy Lynn
Norfolk) wrote:
>>From: "Cyde Weys"
>
>>As far as I know, it's only animals like frogs and
>>lizards that have evolved green camouflage. Why not some other creature?
>
>There are several species of green parrot,
Not just several, hundreds. Not to mention other green non pstticine
birds.
Stacy
John Wendt
> Just a musing: why haven't more animals evolved green camouflaging?
Maybe because there's no way for them to make green hair?
Bigdakine
>From: "Cyde Weys" vze2...@verizon.net
>Date: 6/29/02 10:37 AM Hawaiian Standard Time
>Message-id: <zXoT8.9341$vr5....@nwrddc01.gnilink.net>
>
>
>"Mike Dunford" <mdun...@hawaii.rr.com> wrote in message
>news:Xns923C59DCF5...@66.75.162.198...
>> Patrick James <patj...@newsguy.com> wrote in
>> news:01HW.B94357E80...@enews.newsguy.com:
>>
>> [snip]
>> > Some mammals _are_ greenish-brown: the Indian mongoose, for
>> > instance, ranges in colour from grey to brown to kind of an
>> > olive greenish brown. This does not help 'em much against the #1
>> > killer of mongooses around here: the motorcar. (HM Gov brought
>> > mongooses to the Caribbean to get rid of snakes. Someone forgot
>> > that mongooses also eat eggs, and it's a lot easier to get at
>> > ground dove nests or chicken coops than to go chasing vipers or
>> > boas. Not to mention that there aren't any cobras around here,
>> > and vipers are smarter than cobras, or at least better optimised
>> > for hunting small mammals. oops.)
>>
>> There are similar issues with the mongoose out here in Hawaii. They
>> were originally imported here in an effort to control the rapidly
>> expanding population of rats which had arrived on ships. Only problem
>> with that bright idea was that the mongoose is most active during the
>> day, while the rat...
>
>So what happened with the mongooses?
They started muching on birdies. Or at least their eggs. Now, many of Hawaii's
indigenous birds are in dire straits, such as the Nene (Hawaiian goose)
Stuart
Dr. Stuart A. Weinstein
Ewa Beach Institute of Tectonics
"To err is human, but to really foul things up
requires a creationist"
John Wilkins
> >From: "RHertz"
>
> >The only purpose of the male is to live long enough to mate.
> >After that, he can be eaten by predators and no one will miss him.
> >
>
> Since I am now 45, and my wife had a baby on Tuesday, that is a very cheery
> thought!
>
"Mate" includes paying for their college tuition. You have a few decades
left. After that, it's all downhill.
--
John Wilkins
Sweet Analytics, 'tis thou hast ravished me [Marlowe's Faust]
freehand
Well, we are. Google "human" "eyes" and "sensitive to green". Here's
two links:
http://haywire.csuhayward.edu/~lchristi/Cs6715/Spr02/Notes/ch7.htm
http://www.madsci.org/posts/archives/oct99/939051861.Eg.r.html
But yes, of course an animal evolved to match grass green would look
the same to our eyes. And likely the same as grass to a dog.
Cyde Weys
"John Wendt" <j_w...@acm.org> wrote in message
news:36ab6b9c.02062...@posting.google.com...
That's what I was thinking ... green skin, like on a reptile or something,
is entirely feasible. But for some reason maybe green hair is just
chemically impossible?
Robt Gotschall
vze2...@verizon.net says...
> >
> > Lots of small mammals which live (mostly) on the ground are grey or tan or
> > brown. The list of brown or grey rodents alone is quite long: rats,
> > chipmunks, squirrels, beavers...
>
> I hope you didn't just allege that a beaver is a rodent ...
bea•ver: a large, amphibious rodent of the genus Castor, having sharp
incisors, webbed hind feet, and a flattened tail, noted for its ability
to dam streams with trees, branches, etc.
Copyright © 1966-1994 by Random House Inc., All Rights Reserved.
--
Robt
Every species, not only Homo sapiens,
is in the process of destroying its own environment
Richard Lewontin
Robert Reichenberger
instead of dying because they didn't have what the other creature had
like big teeth. Defensive animal instead of a offensive one.
R. Baldwin
My information came from a lecture about 10 years ago regarding
night-vision imaging equipment. The lecturer began with "What color is
a tree?" and showed spectral response data for foliage. The focus was
trees, not grass, because the subject of interest was flying at
treeline in the dark. I clearly remember from the lecture that the
green foliage in question had more visible red reflectance than green.
I'll have to see if I still have the lecture notes.
You are correct that the infrared reflectance is higher than visible
reflectance at any wavelength. Poking around on the net, it seems that
this depends on the plant species, hydration, and senescence of the
green plant material.
Try reading this:
http://ceos.cnes.fr:8100/cdrom-00b/ceos1/science/baphygb/chap5/ang/cha
p55.htm
Spectral response charts for plant material in various conditions are
provided. The author is Alberte Fischer of Groupement pour le
Développement de la Télédétection Aérospatiale.
Also:
http://gened.emc.maricopa.edu/bio/bio181/BIOBK/BioBookPS.html
By M.J. Farabee. The article discusses the role of chlorohpyl a,
chlorophyl b, and other accessory pigments.
After reading your post and some of the material on the web, I suspect
the lecturer at my company was careless about the particular pigments
responsible for the spectral response of the trees in question.
Regarding the human eye response, perhaps you were thinking of the CIE
tristimulus values, which if I recall correctly are normalized to a
typical human eye response. The human eye most definitely responds
better to green than red. Spectral response is shown on this page for
the three photoreceptors in the human eye.
http://www.cs.unc.edu/~majumder/color/node12.html#SECTION0002400000000
0000000
Author is Aditi Majumder. Paper is "Color Perception and Measurement."
The entire paper is at:
http://www.cs.unc.edu/~majumder/color/paper.html
If you search for CIE and color, you'll find thousands of web pages
discussing the topic.
Regards,
RB
Doug
> Just a musing: why haven't more animals evolved green camouflaging? I
> was looking out my window today, and seeing all of the crows (black),
> squirrels (grey) and other birds (brown) was painfully easy on my GREEN
> grass and GREEN trees. As far as I know, it's only animals like frogs and
> lizards that have evolved green camouflage. Why not some other creature?
> It seems terribly useful to me!
You forgot budgies and green tree kangeroos.
Also many animals are colour blind.
Doug
zosdad
I'm not Canadian, but I think it's a rodent too.
Maybe the poster is from Oregon State and resents the implication...
nic
zosdad
>
> So, in a way, what you said is _sort_ of true ... grass does shine more
> brightly in infrared than in green, and since humans cannot see infrared,
> then it appears to be green to us. But infrared is not red ... it's
> something totally different altogether. Imagine a hypothetical creature
> that can see in the wavelengths 450 (blue) to 750 (infrared). What color
> will chlorophyll appear to them? Green/infrared! In their eyes, it would
> shine most brightly in the green and infrared parts of the spectrum. But
> certainly not in the red part of the spectrum.
>
> I rest my case.
I agree, that NIR (near infrared) spike in reflectance is huge in
remote sensing veg, e.g. Landsat. The "red edge" they call it. If
someone gets a mutant cone that perceives NIR instead of red they
might be rather blinded by the shinyness of the veg. Then again, down
in the NIR it may be that the wavelengths do not have enough power to
cause the necessary electron excitation to fire the vision cascade, so
maybe it's impossible. IIRC plants can perceive the red/NIR
distinction and use it to direct growth (or something).
I think it is true that the proteins used by the red & green cones are
more closely related, and overlap in absorption characteristics, more
than either does with the blue cone pigment (they're all related way
back, see the evolution of color vision FAQ). I think this is why
red-green insensitivity (true colorblindness is quite rare) is more
common than other kinds. Anyway, maybe that is what the person was
thinking about.
Now, if you really want minutae, it turns out you can also identify
plants by the ligno-cellulose absorption in the MIR...
John Wilkins
> "Cyde Weys" <vze2...@verizon.net> wrote...
> > Just a musing: why haven't more animals evolved green camouflaging? I
> > was looking out my window today, and seeing all of the crows (black),
> > squirrels (grey) and other birds (brown) was painfully easy on my GREEN
> > grass and GREEN trees. As far as I know, it's only animals like frogs and
> > lizards that have evolved green camouflage. Why not some other creature?
> > It seems terribly useful to me!
>
> You forgot budgies and green tree kangeroos.
>
> Also many animals are colour blind.
>
> Doug
I know about green budgies, and green (vivid green - they can't be for
camoflage, although they are hard to see in a tree sometimes) rosellas
(a relative of budgies). But green tree kangaroos? I have never heard of
these.
Apart from feral chickens and pheasants, birds in Australia with
substantial green include doves, pigeons, corellas (genus Cacatua),
lorikeets, fig-parrots, parrots, cockatiels, budgerigars, rosellas,
cuckoos, kingfishers, pittas, one gerygone, honeyeaters, a shrike-tit,
catbirds, a European greenfinch, a host of mannikins and a couple of
related parrot-finches. That is just from the illustrations in the
Simpson and Day field guide.
Robin Levett
> Just a musing: why haven't more animals evolved green
camouflaging? I
> was looking out my window today, and seeing all of the crows
(black),
> squirrels (grey) and other birds (brown) was painfully easy on my
GREEN
> grass and GREEN trees. As far as I know, it's only animals like
frogs and
> lizards that have evolved green camouflage. Why not some other
creature?
> It seems terribly useful to me!
>
Funnily enough, Stephen Jay Gould wrote an essay on the subject of
camouflage adaptation - "Red Wings in the Sunset", essay 14 in "Bully
for Borntosaurus".
Abbott Thayer proposed that *all* coloration was evolved primarily for
concealment - leading him to the claim that flamingoes were coloured
red so that they faded into the sunset!
Gould's first point is that this is simply wrong. Quoting Hugh B Cott
("Adaptive coloration in animals", 1940), he gives 3 purposes for
adaptive colorations and patterns; concealment, advertisement and
disguise. The latter 2 do not involve any element of concealment
against the background, and hence there would be no selective pressure
towards green, if green were a camouflage colour.
He does however accept Thayer's big discovery - that countershading is
the most important of all camouflage colorations; not matching of
colours, but matching of light and shade to make the animal look flat.
The next most useful is "ruptive" coloration - breaking up an animal's
coherent outline.
Neither of these depend upon colour matching.
In any event, few animals try to hide against green backgrounds; as
has been pointed out, most grassland is not green, and most forests
are various colours of which the most dominant is not green.
On another topic raised in the thread - it is true that the human eye
is much more sensitive to blue and green light than red, at least at
low light levels; that is why amateur astronomers use red lights to
preserve their dark adaption (professional astronomers don't go
outside in the dark anyway, so don't need dark adaption ;-)).
--
________________________________________________________________
Robin Levett
rle...@ibmrlevett.uklinux.net
(address munged by addition of Big Blue)
Who is reading Bully for Brontosaurus.
Atheist = knows of and uses Occam's Razor
Agnostic = knows of but isn't sure whether to use Occam's Razor
Fundy = what's Ockam's erasure?
___________________________________________________
KCdgw
>> was looking out my window today, and seeing all of the crows (black),
>> squirrels (grey) and other birds (brown) was painfully easy on my GREEN
>> grass and GREEN trees. As far as I know, it's only animals like frogs and
>> lizards that have evolved green camouflage. Why not some other creature?
>> It seems terribly useful to me!
>>
>
You seem to be assuming all predators see in color.
Cheers,
KC
Those who know the truth are not equal to those who love it - Confucius.
R. Baldwin
"zosdad" <niiic...@yahoo.com> wrote in message
news:74227462.0206...@posting.google.com...
On human vision, I did not refer to red-green sensitivity. The color
perceived by human vision is not necessarily what you would expect by
looking at the spectrum of reflected light. There are two reasonse for
this: (1) our eye does not have a flat response to the visible
spectrum, and (2) a variety of spectral responses produce the same
perceived color (metamerism).
The rho, beta, and gamma cones do not have the same amplitude response
or bandwidth.
Lucidor
<snip a bit>
>
> HOWEVER: there is one important thing to note. Chlorophyll actually does
> reflect somewhere in the spectrum more brightly than it does for 550nm.
> Where? In the 750nm range. This is infrared radiation. Humans cannot see
> it. It is not red, it is invisible. This is why plants need sun light, not
> artificial fluorescent light. Sunlight has a LOT of infrared in it;
Err, sorry, but if the plants reflect a frequency, doesn't that mean they
don't use/need it (indeed it may be harmful to them)? If all frequencies were
absorbed, plants would be black, (a desirable goal for many cultivators, e.g.
creating black roses).
Lane Lewis
> >I hope you didn't just allege that a beaver is a rodent ...
>
> Are you suggesting that a beaver is not a rodent? Check out
> http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=Taxonomy
> which specifies for beaver:
> Eukaryota; Metazoa; Chordata; Craniata; Vertebrata;
> Euteleostomi; Mammalia; Eutheria; Rodentia; Sciurognathi;
> Castoridae; Castor
>
No I was refering to the Anole :O)
I have several as pets but I cant tell them apart yet as they keep changing
colors :O(
Lane
Cyde Weys
"Lucidor" <lasse...@aol.com> wrote in message
news:96e6f2e2.02063...@posting.google.com...
> "Cyde Weys" <vze2...@verizon.net> wrote in message
news:<uYqT8.9914$vr5....@nwrddc01.gnilink.net>...
>
> <snip a bit>
>
> >
> > HOWEVER: there is one important thing to note. Chlorophyll actually
does
> > reflect somewhere in the spectrum more brightly than it does for 550nm.
> > Where? In the 750nm range. This is infrared radiation. Humans cannot
see
> > it. It is not red, it is invisible. This is why plants need sun light,
not
> > artificial fluorescent light. Sunlight has a LOT of infrared in it;
>
> Err, sorry, but if the plants reflect a frequency, doesn't that mean they
> don't use/need it (indeed it may be harmful to them)? If all frequencies
were
> absorbed, plants would be black, (a desirable goal for many cultivators,
e.g.
> creating black roses).
Um, shit ... I need to research this further ....
Well, basically, plants are green not because they use the green part of the
spectrum per se, but because chlorophyll is green. And they give off
infrared radiation because they are living, like any other living thing.
Richard S. Norman
Sorry, you do need to research it further.
Plants are indeed green because chlorophyll is green. But chlorophyll
is green specifically because it does NOT absorb or use green light.
All objects emit infrared radiation because of their surface
temperature. It has nothing to do with living. The temperature of a
plant is not noticeably different from that of a non-living object in
its environment; they radiate infrared in exactly the same way. That
radiation peaks around 10 micrometer wavelength.
A completely different story is how much infrared objects
reflect. The radiation of sunlight peaks in the visible region and
drops off with increased wavelength. Still, about 1/4 of the energy
of sunlight is in the infrared range, mostly 0.7 to 1 micrometer.
This radiation far overwhelms the blackbody radiation emitted by all
objects, living or dead. Whether living or dead objects reflect more
infrared light depends strongly on what "color" they happen to be,
measuring "color" in the infrared, of course.
Chris Thompson
ROFL. I graduated from Oregon State and further, I am from New York, which
had a beaver on the state flag *long* before OSU existed. And my mammalogy
professor at OSU said they are rodents.
Chris
Chris Thompson
>
> "Kleuskes & Moos" <some...@over.the.rainbow> wrote in message
> news:afkns2$2k5a$1...@scavenger.euro.net...
> > Cyde Weys wrote:
> >
> > > This still doesn't explain why the females of the species don't have
> green
> > > camouflaging.
> >
> > The best way to camouflage is assuming da dark color and to disappear
into
> > the shadows. Having a green camouflage colour is _only_ effective at
> > daytime.
> >
> > Then there are other reasons:
> >
> > * many, if not most predators are active during the night
>
> I disagree. Not "most" predators ... some.
>
> > * many, if not most predators rely on sense of smell and/or hearing
> instead
> > of sight to seek out prey . Having a camouflage colour simply won't
> help.
>
> Many predators using sight. If a lion is chasing down a zebra, what do
you
> think is going to help more in that last 100 feet, being able to smell
that
> there's a zebra there, or being able to see it and go directly at it?
>
That zebra with its stripes it quite well camouflaged in its environment,
thank you. You have to remember that when something is
standing/sitting/lying absolutely still, it is almost impossible to spot-
especially if it has a broken-up outline, like zebras.
Slightly off-topic but related: Believing that shock treatment is an
effective learning tool, I would often wait until one of my helpers was
quite close to a seabird nest before pointing it out to him or her. I was
never so brave as to wait for them to be a step away, but I let them get
within a meter or so. This is especially effective on the first census day
when people have not yet formed search images. The nests are quite well
camouflaged, but spring into definition when pointed out to you. By far,
Least Tern nests are less visible than Common Terns, since the Leasts simply
wallow out a depression in the sand, while the Commons make a rude nest of
reeds and flotsam.
Chris
Chas. 'Mark' Bee
>
> Just a musing: why haven't more animals evolved green camouflaging? I
> was looking out my window today, and seeing all of the crows (black),
> squirrels (grey) and other birds (brown) was painfully easy on my GREEN
> lizards that have evolved green camouflage. Why not some other creature?
> It seems terribly useful to me!
Most animals don't have color vision.
Thomas McDonald
>
>> Just a musing: why haven't more animals evolved green
>
> camouflaging? I
>
>>was looking out my window today, and seeing all of the crows
>
> (black),
>
>>squirrels (grey) and other birds (brown) was painfully easy on my
>
> GREEN
>
>>grass and GREEN trees. As far as I know, it's only animals like
>
> frogs and
>
>>lizards that have evolved green camouflage. Why not some other
>
> creature?
>
>>It seems terribly useful to me!
>>
>
>
> content than green in the broad spectrum of sunlight reflected by
> chlorophyll. The reason you see it as green is that the human eye has
> a stronger response to green than read.
>
> but to match the visual acuity of their predators rather than the
> visual acuity of Homo sapiens.
>
Good points.
Another issue is that green on the ground (grass, low
evergreens, etc.) is not usually short. Let your yard go
for a couple of months, and you probably could miss a blaze
orange squirrel in it.
Additionally, when grasses are left to grow, they tend to
grow relatively tall. They will also develop lighter-green
or tan seed heads, which move in very light breezes. It
would be difficult to see creatures of almost any color
(provided they were lying still) in those conditions.
(Think of the term "lying in the weeds" as a synonym for
hiding from sight.)
Finally, when "green" things grow tall and complex (as in
trees), other issues such as the shadows they cast and the
various colors of their woody bits will come into play. In
those conditions, nearly any color and/or pattern could find
a micro-environment in which it would be hard for the
pattern's owner to be spotted by those who would wish to do
it harm.
Tom McDonald
Keith Bloom
[....]
> Besides, where in the hell did you get this info that eyes
> perceive green more strongly than red, anyway? As far as I know
> (which is quite a lot, I've taken neurology courses ...), the eyes
> have rods (black/white) and cones (red/green/blue). There is a
> 1:1:1 ratio of different cones in the retina. It makes no sense
> that we should perceive one color as brighter than another.
Since only rods are active in the dark, camouflage based on color
shouldn't matter much at night, when a lot of small animals (and
their predators) are active.
Don't most mammals (other than primates) have rather poor color
vision, anyway?
[....]
> HOWEVER: there is one important thing to note. Chlorophyll
> actually does reflect somewhere in the spectrum more brightly
> than it does for 550nm. Where? In the 750nm range. This is
> infrared radiation. Humans cannot see it. It is not red, it is
> invisible. This is why plants need sun light, not artificial
> fluorescent light. Sunlight has a LOT of infrared in it;
> fluorescent, for the most part, is strong in the visual part of
> the spectrum.
If plants need infrared for photosynthesis, shouldn't they ABSORB
more strongly in the infrared? But then, I thought it was
_ultraviolet_ that was more effective for photosynthesis, not
infrared.
Keith
zosdad
there.
But if you think about bark, dirt, nighttime, colorblind animals (most
mammals are colorblind), deciduous forests, and (especially) the color
of senesced vegetation (e.g., grasslands are generally tan not green),
then you've got part of an answer.
Others have mentioned additional factors.
It's not easy being green...
nic
aka Kermit the Frog, here...
"RHertz" <RHer...@cox.rr.com> wrote in message news:<3xkT8.10821$GF4.5...@twister.southeast.rr.com>...
> "Cyde Weys" <vze2...@verizon.net> wrote in message
> news:x4kT8.6850$vr5....@nwrddc01.gnilink.net...
> > Just a musing: why haven't more animals evolved green camouflaging? I
> > was looking out my window today, and seeing all of the crows (black),
> > squirrels (grey) and other birds (brown) was painfully easy on my GREEN
> > grass and GREEN trees. As far as I know, it's only animals like frogs and
> > lizards that have evolved green camouflage. Why not some other creature?
> > It seems terribly useful to me!
> >
>
> Unless you're trying to MATE with one of them critters. In that case,
> camouflage isn't going to be helpful.
>
> One doesn't go into a singles bar wearing clothes that match the paneling so
> one can disappear. Many, many animals go out of their way to be *visible*.
> Consider the peacock. All in the name of sex.
>
> Note that the males of the species are often the more visible ones. The
> females tend to be duller in color. Why? Because, generally speaking, the
> females are the ones that must nuture the offspring. Now camo becomes an
> advantage. The only purpose of the male is to live long enough to mate.
Cyde Weys
"Richard S. Norman" <rno...@umich.edu> wrote in message
news:s7k0iu8dham4jnon6...@4ax.com...
This is intriguing. A little more illumination, please? I must admit, I am
more ignorant on the topic than I first thought.
So I thought trees used the green and infrared wavelengths ... so why is
that why they reflect back?!?!
Richard S. Norman
<vze2...@verizon.net> wrote:
You have it exactly backwards. White light is a mixture of all the
colors. When it falls on a plant, chlorophyll absorbs the red and the
blue-violet light. Whatever is not absorbed -- that is, the green
light -- is reflected from the leaf and that is what we see.
Similarly, near infrared light as also reflected and shows up in
infrared photographs.
It is the red and the blue-violet light that is used by chlorophyll.
Technically, the amount of light absorbed by a pigment as a function
of wavelength is the "absorption spectrum". The ability of a
photosynthesis to make use of different wavelengths of light is called
the "action spectrum". The fact that the action spectrum for
photosynthesis is the same as the absorption spectrum for chlorophyll
is the evidence that chlorophyll is the essential light-absorbing
element in photosynthesis. It is actually a bit more complicated --
other pigments like carotenoids and anthocyanins can also absorb light
and pass the excitation energy to chlorophyll. Also there are
different varieties of chlorophyll with somewhat different absorption
spectra. Still, the green light tends not to be either absorbed or
used.
Kleuskes & Moos
> You have it exactly backwards. White light is a mixture of all the
> colors. When it falls on a plant, chlorophyll absorbs the red and the
> blue-violet light. Whatever is not absorbed -- that is, the green
> light -- is reflected from the leaf and that is what we see.
> Similarly, near infrared light as also reflected and shows up in
> infrared photographs.
<going off at a tangent again, not subscribing to creationist argument>
The above, of course, being absolutely correct, the fact is also that green
light passes through the leaves, as can be seen on any sunny day looking
through the canopy. Just conjecturing again (and this is _not_ 'kleukses
conjecture'), could it be that light at specific wavelengths are used by a
sensor to get a fix on absolute light intensity (even on the backside of
the leaf, as seen from the sun)?
Using such a mechanism, could yield a significant advantages in order to
regulate processes like citric-acid-cycle (hope i got that one right, but
you know what I mean) and the actual position of the shutters of the pores
(jargon wanting) in the leaf which in turn regulate the amount of
vaporisation, which, effectively regulates the flow of water and nutrients
to said leaf, regulate growth of turgor in order to enable said leaf to
attain an optimum position.
My observation is that some plants are dark-red, instead of green. From
biology-classes long ago, I know synthesis of some plant hormones which
drive growth are light sensitive.
> It is actually a bit more complicated --
> other pigments like carotenoids and anthocyanins can also absorb light
> and pass the excitation energy to chlorophyll.
Question being, If a variety of possible spectra is available, why pick
green to ignore/reflect? Why not, basically, exploit the whole, or at least
more of the spectrum by a balanced mix of pigments?
Mind you. I am only asking questions, so do not be afraid to call me 'dumb
broad' and treat me as such. On many fields of knowledge I can claim no
more that exactly that title. And I _am_ aware that I may be asking that
question the wrong way around. I.e. I see the answer 'Because plants just
tend to use chlorophyl instead of the other possible pigments, dummy'.
Kleuske (... but eager to improve ...)
Suzanne
"Kleuskes & Moos" <some...@over.the.rainbow> wrote in message
receive sunlight. So this is talking about light, and not pigmented
color. Color formation comes from three primary colors, red,
yellow, and blue and all the colors are formed from this. With
light collection, though, all the colors mixed together form white
light. But with opaque or pigmented colored things, black is
produced. So what has been described is light falling on the leaf,
but then returned to our vision as the perception of the color
of green from the pigmented substance in the leaf. It sounds like
what has been said is that the clorophyll, being sort of opaque is
letting all the other light in except green, and that it's very pigment
is filtering out the green light to keep it out, so that what we see
with our vision is the color green. What is not being said entirely
is that they are describing both kinds of colors from light and also
from opaque substance. Now, to grasp this, you kind of have to
think backwards like someone has to do who colors pottery and
paints it, then fires it in a kiln. They paint something one color,
and what comes out is another color. So they have to paint things
what seems to be unnatural to the painter, so that it will turn out
to be what is natural to the viewers...such as painting a red rose
starts out with something like painting it green, or the opposite
color on the spectrum wheel. In this kind of way, the leaves
are painted with colors of light, and they reflect the colors in a
different way when the light hits the pigment within the leaf that
we call the chloroplasts. So what you see when you look at
something opaque that is green, is the color of the light that it
would not absorb. I'm not sure that the word should be that
a leaf reflects green so much as it is that it deflects green. While
what we see of a leaf is green, it must be the absence of green
if we only could see it, in order to look green to us, in other
words.
>
Suzanne
Richard Uhrich
<snip accurate but meandering irrelevant discussion of pigments and
questionable stuff about glazing>
> While
> what we see of a leaf is green, it must be the absence of green
> if we only could see it, in order to look green to us, in other
> words.
>
> Suzanne
>
>
She's baaa-aaaaaak!
Green leaves scatter light with green frequency (which could also be
produced by blue and yellow pigments, but is not relevant to natural,
unpainted leaves), and absorb other frequencies.
--
Richard Uhrich
---
An unfortunate corollary of having a small minority knowing more and
more about less and less is a large majority knowing less and less about
more and more. --- Mike Gazzanaga, "The Mind's Past"
Richard S. Norman
You do have some good points and questions. First, I was careless
in saying plants "reflect" green light. Of course they reflect some,
scatter a lot more, and allow some to be transmitted through the leaf.
Yes, a lot of light gets through the leaves and this is much richer in
green than ordinary sunlight.
I am desperately trying to remember what my colleage, an ecologist
and plant physiologist, told me about that. I know that in past years
we used to take our intro biology classes out into an area of clear
sky and an area in a forest under a leaf cover and measure the
relative intensity of blue, green, red, and far red light. But for
the life of me, I can't exactly rememberthe details. I do believe the
plants on the forest floor can in fact detect that color difference.
There are a number of light-sensitive pigments that are not associated
with photosynthesis, but with the plant hormone system as you mention.
So phototropism, light-sensitive seed germination, control of
flowering, and the opening of the stomata (as you mention) are things
that can be influenced differently by light of different colors.
In plants with dark red leaves, the chlorophyll is hidden by the high
concentration of reds, probably anthocyanins. I suspect (but I am not
sure) that plants with a lot of anthocyanins and with a red color are
plants that naturally tend to grow in the forest floor and so receive
an excess of green light and a deficiency of blue and red. Still,
unless you have a really dense canopy of leaves so the understory is
really in deep shade, a substantial amount of even red and blue light
does make it through the leaves.
Why pick the red and blue to use and leave behind the green?
Unfortunately, that is not the kind of question that is easily
answered. The usual reason is that is it not "easy" to come
up with a biological molecule that can take the energy of sunlight and
make it excite electrons that can then be passed on into other
biochemical processes. And when you do, it will tend to absorb light
in a fairly narrow region -- that is, it will have a striking color.
Cholorophyll works effectively and, with the assistance of the
"accessory" red pigments, manage to make good use of light. So
chlorophyll it is. The blue-green bacterial/algae first came up with
this system and all the photsynthetic plants and algae make use of the
same one with minor variations in the kind of chlorophyll synthesized.
Note that a plant that looks green does not really lack red or orange
pigments. That is obvious in temperate climates during autumn, when
the leaves change color. They don't really "turn" red, orange, or
yellow. Instead, the breakdown of the chlorophyll just reveals the
other color pigments that were there all the time. And those pigments
help the plant use green light.
R. Baldwin
news:PiwU8.148$fe6.2...@newssvr17.news.prodigy.com...
This is a bit misleading. It reads like an artists' concept of color.
Sunlight is white light because it is broadband electromagnetic
radiation containing all the visible wavelengths (also UV and IR).
Color is perceived when visible electromagnetic energy stimulates the
red, green, and blue cone photoreceptors in the human eye (they have
peak wavelengths at 565, 535, and 440 nm, respectively).
The brain interprets the combined three stimuli as a color, the effect
of which may be approximated by using the 1931 Commission
Internationale de Eclairage (CIE) standard color matching functions x,
y, z and looking up (x, y) on the CIE chart (z may be omitted because
x, y, and z are normalized, as color and intensity are perceived
distinctly). The CIE color can be mapped to a number of other
mathematical color spaces (RGB, LUV, HSI, etc.).
The reason we have three primary colors is because we have three
different color photoreceptors in the eye. Primary colors are only a
function of human perception and have nothing to do with the physical
world around us.
A perceived color is the brain's interpretation of received light with
varying amplitude of electromagnetic energy vs. wavelength. Many
different received spectra will map to the same color (monomerism).
For example, we perceive the spectra of both household fluorescent and
incandescent lamps as white, even though the fluorescent lamps emit
narrowband light in the red, green and blue bands while the
incandescent lamps emit broadband light with a spectrum close to
sunlight.
Without going into the quantum effects, all matter absorbs, reflects,
or transmits electromagnetic energy across the entire EM spectrum at
varying amplitudes. (Reflect is the correct term, not deflect). The
combination of reflected and transmitted visible EM energy that heads
in the direction of your eye determines the color you see.
Colorants such as pigments or dyes reflect, absorb or transmit EM
across the visible spectrum from whatever light spectrum is available,
and the human eye perceives the reflected or transmitted light as a
color. This is affected by the position of the light source(s) and
whether the matter interface is specular or diffuse.
Besides chlorophyll a, photosynthetic organisms can include other
pigments such as chlorophyll b, xanthophylls and carotenoids. For most
photosynthetic organisms, the spectrum of the reflected light is
perceived by humans as green.
In the earth's atmosphere diffuse light is plentiful, so any
transmitted light through an object will be combined with reflected
light. This provides a simplified explanation of why both reflected
and transmitted light for a thin leaf appear green.
(This has been a good thread - I've picked up good info about plant
pigments and learned that some of the information I had about them was
incorrect.)
Kleuskes & Moos
You are like a pear tree in late summer. I will keep shaking it.
I like pears.
I am impressed by the stuff available on the net. Shame there ain't
more people using it.
<semi-schwarzeneggerette voice>
I'll be back...
</semi-schwarzeneggerette voice>
Got some reading to do.
Tjuus,
Kleuske.
Sven Silow
In a forest only a few percent (or less) of the useful wavelengths
reaches the ground and most of the light a plant at the forest floor
receives might be from occasional sunlight "flashes". The trees are
awfully effective. (And this is the reason for the rapid growth of the
understory plants of deciduous forests in spring before the trees get
their leaves.)
>I am desperately trying to remember what my colleage, an ecologist
>and plant physiologist, told me about that. I know that in past years
>we used to take our intro biology classes out into an area of clear
>sky and an area in a forest under a leaf cover and measure the
>relative intensity of blue, green, red, and far red light. But for
>the life of me, I can't exactly rememberthe details. I do believe the
>plants on the forest floor can in fact detect that color difference.
>There are a number of light-sensitive pigments that are not associated
>with photosynthesis, but with the plant hormone system as you mention.
>So phototropism, light-sensitive seed germination, control of
>flowering, and the opening of the stomata (as you mention) are things
>that can be influenced differently by light of different colors.
A pigment that is responsible for such functions is phytochrome, whose
two forms are sensible for red and infrared light respectively (it
shifts between two forms P-730 and P-660). During the daytime it gets
converted from P-660 to the IR-sensitive P-730 (it is enough with a
short flash of light). During night it slowly converts into the red
sensitive P-660 form again. Thus only during long nights there will be
a period without P-730 and this period is believed to be essential for
certain processes to occur. I hope that science have advanced and that
more is known today (plant physiology is - or at least was - a very
"backward" science, far behind human physiology; a question of
resources of course).
>In plants with dark red leaves, the chlorophyll is hidden by the high
>concentration of reds, probably anthocyanins. I suspect (but I am not
>sure) that plants with a lot of anthocyanins and with a red color are
>plants that naturally tend to grow in the forest floor and so receive
>an excess of green light and a deficiency of blue and red. Still,
>unless you have a really dense canopy of leaves so the understory is
>really in deep shade, a substantial amount of even red and blue light
>does make it through the leaves.
Anthocyanins are pigments (red and blue) that is excreted into the
vacuole and thus are not engaged in physiological processes (they are
the result of physiological processes, but else). Often they are
symptoms of stress (like drought and some deficiencies), but many
plants "wilfully" produce them for different reasons (one being red or
blue flowers). BTW the colour of anthocyanins are pH dependent -
lithmus paper - put a blue flower in acid water or a red in basic and
watch the color change starting at the veins ('acid water' doesn't
mean konc H2SO4!). If you don't have a flower you can use red cabbage,
red beets, blueberries... (and you have a lot of acid and basic stuff
in your home: most cleaning products for instance).
IIRC (I studied plant physiology in the 70's and much of it is
forgotten and the rest might be outdated) anthocyanins is also a sign
of access carbohydrates or phosphorus deficiency and it can be a
result of *insufficient* light.
"Sunlight tolerant" plants often have small, lobed, thin (and thus
lighter green) leaves to improve heat exchange, while shadow tolerant
plants have larger, entire, thicker (with more pigments and thus also
darker leaves - this is usually also true of leaves on the same tree).
If the lighting conditions are altered (which can be noted by moving a
house-plant - most of mine experience this right now) plants often
drop their leaves (like Ficus benjamina!) and grow new ones. Now other
factors plays a big role for leaf properties of course (desert plants
have thick leaves to save/store water, not because of insufficient
light).
But I have (as far as I remember) never heard that shadow *tolerance*
and anthocyanin should be related, though. But perhaps I didn't listen
carefully enough.
>Why pick the red and blue to use and leave behind the green?
One reason, that also is implied above, is *heat*. A plant leaf in
full sunshine could easily be overheated if it was black (i.e.
absorbed the full spectrum). A peak in the high energy blue, another
in the low energy red, and reflect the rest (or let it pass through).
Unnecessary absorbtion that only produced heat would be a risk of
damage and especially it would increase transpiration (and water is a
thing most plants tend to be careful with). Increased transpiration ->
closing of stomata -> CO2 deficiency -> reduced/stopped
photosynthesis. Bad strategy.
>Unfortunately, that is not the kind of question that is easily
>answered. The usual reason is that is it not "easy" to come
>up with a biological molecule that can take the energy of sunlight and
>make it excite electrons that can then be passed on into other
>biochemical processes. And when you do, it will tend to absorb light
>in a fairly narrow region -- that is, it will have a striking color.
>Cholorophyll works effectively and, with the assistance of the
>"accessory" red pigments, manage to make good use of light. So
>chlorophyll it is. The blue-green bacterial/algae first came up with
>this system and all the photsynthetic plants and algae make use of the
>same one with minor variations in the kind of chlorophyll synthesized.
A thing that can also be noted is the colour of *red* algae, who lives
at the "limit of light" in the seas. Red light is absorbed before
(i.e. higher up than) the shorter wavelengths in water. But the red
algae produces a stuff named phycoerythrin that absorbs in the
green/blue part of the spectrum and this phycoerythrin then "feeds"
chlorophyll A with "red light"-energy so that it functions normally (I
don't know any details of how this is done). Judging by the colour of
red algae it looks to me like their amount of chlorofyll A is quite
low and that phycoerythrin has taken over most of the job as "light
catcher".
>Note that a plant that looks green does not really lack red or orange
>pigments. That is obvious in temperate climates during autumn, when
>the leaves change color. They don't really "turn" red, orange, or
>yellow. Instead, the breakdown of the chlorophyll just reveals the
>other color pigments that were there all the time. And those pigments
>help the plant use green light.
Some of those "autumn pigments" are also produced in the autumn - like
anthocyanins because of incresed carbohydrate levels for instance.
(During the later part of the year, when the production of
seeds/fruits are over, perennial plants "concentrate" on producing
carbohydrates to use in the next spring.)
Sven
(who probably won't be able to answer to any replies due to a coming
period of "abscense")
Bjoern Feuerbacher
>
[snip all]
Oh, hi again, Suzanne, here you are! How long have you evaded answering
my questions now? I think it is close to two months! Suzanne, aren't you
able to give evidence for your assertions?
You *still* haven't given done this for the following assertions!
1) The Hebrews at the time when Psalm 19 was written knew that the Earth
is round and goes around the sun (your own link said that the Rabbis
thought the Earth is flat!)
2) The motion of the sun in Psalm 19 has anything to do with the orbit
of the sun in the galaxy.
3) The sun has an orbit in the galaxy which is independent of the
galactic rotation.
4) There is a black hole in our galaxy which moves towards us.
5) Scientists plan to move Earth out of the solar system because of this
Black Hole (no, Suzanne, not your usual link which talks about the sun
becoming a red giant, please!)
There were more things - but these are all I remember for now.
I'm waiting for you...
Greetings,
Bjoern
Pechvarry
> Just a musing: why haven't more animals evolved green camouflaging? I
> was looking out my window today, and seeing all of the crows (black),
Crows are more often predators than prey. When preyed upon, the are
most vulnerable to owl attacks. At night. To which being black is a
decent defense.
> squirrels (grey)
Squirrels spend most of their time in trees, not on grass. And in
trees they don't tend to dangle cluthcing green leaves; they tend to
perch on greyish branches, where being grey is useful camouflage.
> and other birds (brown) was painfully easy on my GREEN grass and GREEN
> trees. As far as I know, it's only animals like frogs and lizards that have
> evolved green camouflage.
There are lots of green parrots.
Being green has its uses, for some critters in some situations. Being
other colors has lots of other uses for other critters in other
situations.
Pechvarry
Richard Uhrich
A few more of my favorites were that diatoms arise by virgin birth from
sea water, skepticism and surmise that plants have parents, that the
earth's crust is supported on the core by yet undiscovered "pillars,"
and now:
> While
> what we see of a leaf is green, it must be the absence of green
> if we only could see it, in order to look green to us, in other
> words.
--
Richard Uhrich
---
An unfortunate corollary of having a small minority knowing more and
more about less and less is a large majority knowing less and less about
more and more. --- Mike Gazzanaga, "The Mind's Past"
(Corollary II: Most of the minority is within the majority.)
Ron Okimoto
> "Kleuskes & Moos" <some...@over.the.rainbow> wrote in message
> news:afkns2$2k5a$1...@scavenger.euro.net...
> > Cyde Weys wrote:
> >
> > > This still doesn't explain why the females of the species don't have
> green
> > > camouflaging.
> >
> > The best way to camouflage is assuming da dark color and to disappear into
> > the shadows. Having a green camouflage colour is _only_ effective at
> > daytime.
> >
> > Then there are other reasons:
> >
> > * many, if not most predators are active during the night
>
> I disagree. Not "most" predators ... some.
>
> > * many, if not most predators rely on sense of smell and/or hearing
> instead
> > of sight to seek out prey . Having a camouflage colour simply won't
> help.
>
> Many predators using sight. If a lion is chasing down a zebra, what do you
> think is going to help more in that last 100 feet, being able to smell that
> there's a zebra there, or being able to see it and go directly at it?
Zebras would not benefit from being green. They spend most of their
time on the open plain on a dried grass background. Broken shadows
with scrub could make their pattern hard to detect, and some people
think that being herd animals, zebra hide among themselves. The
shifting herd confuses the predator and people have film footage of
lions missing their mark by quite a bit when they go after zebra and
jump where there is no zebra in the melee.
You need blue and yellow to make green. I don't know how frogs do it,
but mammals can't seem to produce blue in their fur. They can put
carotenoids (yellows), pheomelanins (reds) and eumelanins (black), but
the blue isn't available. You can get bluish skin for a number of
reasons, but you can't seem to get blue fur. Birds don't produce a
blue pigment the blue feathers are the result of the structure of the
feather and they look blue due to the light refraction. Without other
pigments you get blue like bluejays, combined with yellow you get the
green that you see in many parrots. So you do see green in animals
that can produce the color like in amphibians reptiles and birds, but
you don't see the blue in mammals, probably because they are covered
with hair and you can't produce a blue color on hair like you can in
feathers and scales. Sloths are greenish, but it is due to the stuff
that grows in their fur.
Green isn't the best camoflage even for birds that spend most of their
time on the grass or in the trees. When they are feeding they can fly
away from predators, but when they are on the nest a darker cover
seems to be best. A robin may have a red breast, but you will be hard
pressed to see the female motionless on her nest with only her back
showing. It is strange that the green birds seem to nest in holes and
not on the branches. It may be that green just isn't a good color for
nesting even in trees.
Ron Okimoto
Richard Uhrich
Ron, don't make the same mistake as Susan. Green *pigment* requires blue
and green. Animals aren't painted.
>
> Green isn't the best camoflage even for birds that spend most of their
> time on the grass or in the trees. When they are feeding they can fly
> away from predators, but when they are on the nest a darker cover
> seems to be best. A robin may have a red breast, but you will be hard
> pressed to see the female motionless on her nest with only her back
> showing. It is strange that the green birds seem to nest in holes and
> not on the branches. It may be that green just isn't a good color for
> nesting even in trees.
>
> Ron Okimoto
>
>
--
Ron Okimoto
I think that you meant blue and "yellow."
I'm not making any mistake. I've just stated the way that animals
produce the green color. Mammals have not developed a means to create
green in their fur so you can't expect them to use it as camoflage.
I also pointed out that even the birds that have developed green, hide
in places where the color doesn't matter when they are most vunerable
(nesting), so green may not be optimal for overall selection.
Ron Okimoto
Richard Uhrich
Yes. And I meant Suzanne, not Susan.
>
> I'm not making any mistake. I've just stated the way that animals
> produce the green color. Mammals have not developed a means to create
> green in their fur so you can't expect them to use it as camoflage.
OK. But why did you discuss the difficulties of blue fur rather than
green if you did not mean "You *need* blue and yellow to make green"?
(Rhetorical)
Richard
Sven Silow
>Ron, don't make the same mistake as Susan. Green *pigment* requires blue
>and green. Animals aren't painted.
Colours of feathers are caused by refraction/interference (mainly
blue) due to the structure of the feather, and pigments. The main
pigments are melanin (black/brown) and carotenoids (yellow - red).
Thus green colour is blue (structural) plus yellow (pigment).
Sven
Richard Uhrich
Is that the only way green can be created? How is chlorophyl colored?
Ron said, "You *need* blue and yellow to make green." My monitor is RGB,
not CYMK like my printer.
Richard S. Norman
<uhr...@san.rr.com> wrote:
>Sven Silow wrote:
>
>> Richard Uhrich <uhr...@san.rr.com> penmanshipped:
>>
>>
>>
>>>Ron, don't make the same mistake as Susan. Green *pigment* requires blue
>>>and green. Animals aren't painted.
>>>
>>
>> Colours of feathers are caused by refraction/interference (mainly
>> blue) due to the structure of the feather, and pigments. The main
>> pigments are melanin (black/brown) and carotenoids (yellow - red).
>> Thus green colour is blue (structural) plus yellow (pigment).
>>
>> Sven
>>
>>
>
>Is that the only way green can be created? How is chlorophyl colored?
>Ron said, "You *need* blue and yellow to make green." My monitor is RGB,
> not CYMK like my printer.
Many things are possible. But the fact is that mammals ca not
produce a wide range of coloration in their fur. Birds can make a
wider range in their feathers. And chromatophores in the skin of
fish, amphibians, reptiles, and arthropods are even more versatile.
Still, animals cannot produce a green pigment. Some allow or
encourage green algae to grow in them to produce a green color. Some
use light interference in highly structured crystalline materials to
produce green. But animals simply don't make green!
Now, if I were the intelligent designer, I would have done things
differently. But that is the way it is.
Sven Silow
>Sven Silow wrote:
>
>> Richard Uhrich <uhr...@san.rr.com> penmanshipped:
>>
>>
>>
>>>Ron, don't make the same mistake as Susan. Green *pigment* requires blue
>>>and green. Animals aren't painted.
>>>
>>
>> Colours of feathers are caused by refraction/interference (mainly
>> blue) due to the structure of the feather, and pigments. The main
>> pigments are melanin (black/brown) and carotenoids (yellow - red).
>> Thus green colour is blue (structural) plus yellow (pigment).
>>
>> Sven
>>
>>
>
>Is that the only way green can be created?
AFAIK birds have no green pigments, but as I couldn't tell whether
this was true for other animals I did a search and found this
extensive page that seems to contain lots and lots of information
(much more than the limited knowledge I can supply) - so I let it talk
for itself:
http://www.tightrope.it/nicolaus/origins.htm
(I shall read it myself after posting this reply.)
>How is chlorophyl colored?
Feathers doesn't contain chlorophyll and plants, algae, cyanobacteria
are not birds. Else chlorophyll gets its colour from reflecting green
light, while absorbing red and blue.
>Ron said, "You *need* blue and yellow to make green." My monitor is RGB,
> not CYMK like my printer.
The difference between RBG and CMY (the K means 'black' which is added
because CMY gives a brownish colour through not absorbing everything)
is that RBG works with emitted light (addition) and CMY with absorbed
(subtraction).
RBG is easy to understand - we have three kinds of cones that are
sensitive to red, green and blue respectively.
Printing in CMY is based on reflection from a white surface and by
deleting (through absorbtion) the reflected RGB "constituents". Yellow
absorbs Blue while it is transparent for Green and Red; Magenta
absorbs Green while it is transparent for Red and Blue; Cyan absorbs
Red while it is transparent for Green and Blue. Thus if you mix two of
your CMY colours on a white paper you will get R, G or B [by
subtracting the two others from white] and if you mix two of your RBG
colours on your monitor you will get C, M or Y [by adding emiited
ligt].
How CMY works:
White Yellow Yellow Cyan Green
light pigment light pigment light
Red ---------------> | -----------------> |
Green -------------> | -----------------> | ------------------->
Blue --------------> | |
When a TV-channel is not sending out a program there is often a test
screen (I guess that this applies to most countries) with different
lines and stuff, including coloured fields. Those are R, B, G, R+B,
R+G and B+G: thus you have all six colours (and sometimes more by
mixing with different strength).
That Y in CMY doesn't really look like R+G in RBG etc... is an effect
of the shape of the absorbtion spectra of our cones and of the CMY
pigments and that white light is a continuous spectrum (not just three
lines from the spectrum as the white from your monitor).
Sven
Ron Okimoto
Because that is the only way that I know higher vertebrates make the
color green. Living chromatophores are used in some animals, but they
don't work in fur.
Ron Okimoto
Richard Uhrich
OK, you can't get green fur directly, and you can't get blue fur either.
Simple enough.
I don't mean to be obtuse, but you said, "You need blue and yellow to
make green," and went on about how you couldn't get blue fur. Thus I was
given the impression you meant the statement as it appeared, without
qualifications.
No big deal, right?
--
Richard Uhrich
Richard Uhrich
Thanks, Sven. But we're way off on a tangent. I understand color theory
in pigments and light; Suzanne is the one who does not understand it.
When Ron Okimoto said, "You need blue and yellow to make green," without
any qualification, I incorrectly assumed he meant it without
qualification. We all agree, now that he's explained.