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What Birds See [evolution of the eye]
Scientific American ^
| July 2006
| Timothy H. Goldsmith
Posted on 07/03/2006 10:05:56 AM PDT by doc30
click here to read article
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Essentially, the article says that fish, reptiles, amphibians and birds all evolved the capacity to see in the UV in the form of tetrachromic vision. Mammals were once that way, too. But during the time of the dinosaurs, mammals became nocturnal and lost two of the four receptors but gained better light sensitivity for nocturnal vision. Hence, all mammals are dichromatic. A certain lineage of primates experienced a mutation that shifted slightly one of the color receptors and evolved a weak version of trichromatic vision. Humans are part of that lineage. So, for those that say the eye could not have evolved because it is too complicated, be aware that it has now been shown that our eyes have de-evolved from non-mammilian vertebrates. They became much less 'complex' then genetic changes re-evolved some lost features. It sahows evolution works in both 'directions.'
One of my favorite examples from the article was about how birds of prey, kestrels in particular can see UV. Rodents leave urine-based scent trails, but urine has a 'UV color' that these birds can see. If you were a kestrel, you could see lines of urine trails zig-zagging across the coutryside and follow a trail to find your lunch. Also, birds without sexual dimorphism (i.e. you can't tell male from female visually) actually do have sexually dimorphic coloration in the UV. Other birds can see it but we can't.
1
posted on
07/03/2006 10:05:59 AM PDT
by
doc30
To: PatrickHenry
2
posted on
07/03/2006 10:06:29 AM PDT
by
doc30
(Democrats are to morals what and Etch-A-Sketch is to Art.)
To: doc30
To: Central Scrutiniser
4
posted on
07/03/2006 10:12:17 AM PDT
by
GSlob
To: doc30
Thanks for the post. Interesting read.
5
posted on
07/03/2006 10:12:51 AM PDT
by
RadioAstronomer
(Senior member of Darwin Central)
To: Central Scrutiniser
The cartoon was funny, however, it oversimplifies what a creationists means when s/he says that they don't believe in evolution they mean that they don't believe that random mutations can add complexity to an organism that didn't already have it in it's genetic code, and that successive generations of bacteria won't mutate into a frog, no matter how many generations you have.
To: VadeRetro; Junior; longshadow; RadioAstronomer; Doctor Stochastic; js1138; Shryke; RightWhale; ...
7
posted on
07/03/2006 10:15:05 AM PDT
by
PatrickHenry
(Free enterprise, individual rights, democracy, and evolution -- no centralized planning.)
To: doc30
If you were a kestrel, you could see lines of urine trails zig-zagging across the coutryside and follow a trail to find your lunch. I wonder if the nocturnal Owls have the ability to see in the UV?
To: RadioAstronomer
...if you believe in that sort of thing...
9
posted on
07/03/2006 10:16:40 AM PDT
by
jagusafr
(The proof that we are rightly related to God is that we do our best whether we feel inspired or not")
To: Central Scrutiniser
10
posted on
07/03/2006 10:17:56 AM PDT
by
sully777
(wWBBD: What would Brian Boitano do?)
To: Central Scrutiniser
You do know that this is a Conservative site, right?
11
posted on
07/03/2006 10:18:56 AM PDT
by
Windsong
(Jesus Saves, but Buddha makes incremental backups)
To: conservativefreak
If one is making one's point with a Gary Trudeau cartoon they should begin to question if they understand the issue at all. It's not surprising that they wouldn't understand the creationist point of view.
Liberals always simplify and label things they disagree with because it's easier than thinking. Trudeau is the poster boy for that type of argument.
12
posted on
07/03/2006 10:19:00 AM PDT
by
hometoroost
(TSA = Thousands Standing Around)
To: conservativefreak
I agree with your comment, except the part where you said the cartoon was funny.
To: doc30
Five posts until some horse's patoot turns this article into an opportunity for another infantile crevo pissing contest. Counting down...
To: doc30
There was a show about bird vision on Discovery a few years back.
At the very back of the retina, birds have this sort of "dimple" formation, packed with visual receptors.
The net result is that for the peripheral vision of birds, everything is seen as normal. But for a small circular section in the center of their field of vision, everything is magnified. So if they look straight at something, they "zoom in" on it.
15
posted on
07/03/2006 10:21:23 AM PDT
by
djf
(I'm not Islamophobic. But I am bombophobic. Same thing, I guess...)
To: Central Scrutiniser
I saw that comic yesterday and thought to myself that it was a poor argument. The point should have been, "Do you want me to treat you for TB, or the AIDs that it evolved into." MY point is that it is the same thing. TB is TB, with variation, and I don't think many of those who don't believe evolution to be fact are arguing that organisms don't adapt and change. The point is TB doesn't be come Aids, or plankton, or a cow.
To: Billthedrill
Five posts until some horse's patoot turns this article into an opportunity for another infantile crevo pissing contest. Why not? It only took 14 for someone to throw a stream...
17
posted on
07/03/2006 10:25:38 AM PDT
by
pgyanke
(Christ embraces sinners; liberals embrace the sin.)
To: Windsong
You know that a person can believe in evolution, in God, and in Jesus and still be conservative. Oh my god a Bhuddist or a Hindu could be conservatives also and have a completely different set of creation beliefs. Hey I had a thought I think even an atheist could be a conservative.
18
posted on
07/03/2006 10:25:48 AM PDT
by
Sentis
(You said the world doesn't need salvation so why do I hear it calling out for a Savior.)
To: hometoroost
To use a Trudeau cartoon to make a point, it's evident that this whole discussion about Darwinism on FR has less to do with science, and more to do with a philosophical agenda.
To: doc30
Its such a shock that we are at the top of the food chain despite being "de-evolved."
20
posted on
07/03/2006 10:27:02 AM PDT
by
BaBaStooey
(I heart Emma Caulfield.)
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