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RE: Did Feathers Evolve for Dispaly? We Still Don't Know!



Mickey Rowe writes:

> Maybe you should wait until someone makes that claim before you attack
> it.

Nobody "attacked" anything. Nothing in my post reads as an "attack", which I 
take to mean an aggressive assault, and you completely missed the part where I 
mentioned how marvelous Benton et al.'s new work on the life coloration of 
_Sinosauropteryx_ is and congratulated them for it.

> How do you translate "we therefore suggest" to "this discovery
> provides convincing evidence"?

They wouldn't be suggesting a hypothesis if they didn't think that there was 
convincing evidence for it, now would they?

> I'm all for demanding evidence, but when someone suggests a hypothesis
> you shouldn't go all Katie bar the door on them.

Oh dear. No one ever "Katie barred the door" on anybody.

> Seriously? We know points 3 and 4 but we don't know point 1 and a
> non-flying animal walking around with colorful feathers 125 million
> years ago provides the same evidence as an animal living 10,000 years
> ago when the issue is trying to understand form and function in
> animals that lived 150 million years ago? These are the positions
> you're staking out?

What does geologic time have to do with anything? And haven't you ever heard of 
'making an anology'?

> So relevant data adds nothing to our understanding?

Tsk, tsk. That was the crux of my post - that the colors of _Sinosauropteryx_'s 
feathers is *not* terribly relevant to our understanding of why feathers 
evolved in the first place; we always knew that the feathers of 
_Sinosauropteryx_ were most probably *some* sort of color (even it was white), 
so the discovery of the exact nature of said colors says little if anything 
about the origin of feathers.

I'm afraid you've missed the whole entire point.

> And do you really
> want us to believe you're examining your own beliefs with this much
> skepticism?

1) I am not examining Benton et al.'s beliefs with an unusual or unnecessary 
amount of skepticism, only the healthy dose of skepticism that I feel is called 
for, and 2) you (and those who you refer to as "us") can beleive whatever you 
(they) want.

> What can you tell us about the color vision of a lion?

That lions lack color vision (or at least well-developed color vision); anyone 
who wants to verify this claim can easily and painlessly do so.

> To a lion, does the vegetation in the Serengeti have the same hue as
> the stripes on a zebra? What evidence can you provide to support the
> idea that zebra stripes make individual zebras difficult for lions to
> discern?

Is this or is this not the most widely accepted hypothesis regarding the 
purpose of the zebra's stripes? Either A) it is, or B) I am horrendously 
misinformed.

> Or even that it makes any difference if it's true? How
> often does a lion try to chase a zebra surrounded by other zebras?

Don't lions usually attempt to single out an individual from the rest of the 
herd? And isn't singling out a individual necessary, as zebras are herd animals 
that rarely travel alone? Seriously.

> Then let's toss out that you haven't said anything about the visual
> systems of the animals that lived around Sinosauropteryx or the
> environment in which it lived. You say "orange and white banded
> coloration would serve purposes of camouflage just as well". And you
> know this how?

Let's see here. The fawns of many deer species are tan-orange with white 
markings, and this coloration camouflages the animal from predators whilst its 
parent is searching for food and the like. Corn snakes are orange with red 
dorsal blotches edged in white, and this coloration camouflages the snake 
against the tree bark and leaf litter of its forest habitat. Red pandas are 
orange-red with prominent white bands on the tail (a coloration very similar to 
that of _Sinosauropteryx_), and this coloration serves as camouflage against 
the lichen-covered trees it inhabits.

Hopefully that explains everything, and as with the claim that lions lack color 
vision, anyone who wants to verify these claims about camouflage can easily do 
so.

> And your gripe is that Benton et al. are pushing their
> hypothesis too strongly?

No. My "gripe" is that the discovery that _Sinosauropteryx_ had 
orange-and-white-colored feathers does not provide new evidence that feathers 
evolved for display, and does not deem said hypothesis more robust than it was 
previously. See my responses above.

> Wow.

"Wow" indeed.

And the accusation at the beginning of your post, that I created a straw man, 
is ironic, considering that your entire characterization of *my* post was a 
straw man!

~ Michael


> Date: Thu, 28 Jan 2010 21:02:55 -0800
> From: mickeyprowe@gmail.com
> To: dinosaur@usc.edu
> Subject: Re: Did Feathers Evolve for Dispaly? We Still Don't Know!
>
> Michael Erickson creates a straw man:
>
>> I am addressing the claim that this discovery provides convincing evidence
>> that feathers (in this post I will be including protofeathers under the 
>> blanket
>> term "feathers") initially evolved for display.
>
> Maybe you should wait until someone makes that claim before you attack
> it. Even in your very own message the quote is:
>
> "We therefore suggest that feathers first arose as agents for colour display"
>
> How do you translate "we therefore suggest" to "this discovery
> provides convincing evidence"?
>
> I'm all for demanding evidence, but when someone suggests a hypothesis
> you shouldn't go all Katie bar the door on them.
>
> Next:
>
> (1)
>> For one thing, we don't actually know that _Sinosauropteryx_ itself
>> used its feathers in display
>
> and:
>
> (2)
>> Second, even if _Sinosauropteryx_ itself *did* use its vivid color patterns
>> in display, that the animal had striking plumage in no way even begins to
>> support the hypothesis that feathers themselves evolved for display, or at
>> least not any more than that the bright and vivid plumage of many modern
>> birds provides evidence for such.
>
> but:
>
> (3)
>> Zebras possess extremely bold black-and-white striped fur coloration, so
>> that predators examining the herd have a difficult time differentiating one
>> potential target from another;
>
> and:
>
> (4)
>> in the eyes of the color-blind mammalian predator, individuals and their
>> outlines disappear in a sea of stripes
>
> Seriously? We know points 3 and 4 but we don't know point 1 and a
> non-flying animal walking around with colorful feathers 125 million
> years ago provides the same evidence as an animal living 10,000 years
> ago when the issue is trying to understand form and function in
> animals that lived 150 million years ago? These are the positions
> you're staking out?
>
>> The point is that the hypothesis that feathers initially evolved as display
>> devices is really no more robust today than it was yesterday, or the day
>> before that, or the day before that.
>
> So relevant data adds nothing to our understanding? And do you really
> want us to believe you're examining your own beliefs with this much
> skepticism? What can you tell us about the color vision of a lion?
> To a lion, does the vegetation in the Serengeti have the same hue as
> the stripes on a zebra? What evidence can you provide to support the
> idea that zebra stripes make individual zebras difficult for lions to
> discern? Or even that it makes any difference if it's true? How
> often does a lion try to chase a zebra surrounded by other zebras?
>
> Then let's toss out that you haven't said anything about the visual
> systems of the animals that lived around Sinosauropteryx or the
> environment in which it lived. You say "orange and white banded
> coloration would serve purposes of camouflage just as well". And you
> know this how? And your gripe is that Benton et al. are pushing their
> hypothesis too strongly?
>
> Wow.
>
> --
> Mickey Rowe (MickeyPRowe@gmail.com                                      
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