[doc30]

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.

[LiteKeeper]

YEC INTREP

[bert]

.......One of my favorite examples from the article was about how birds of prey, kestrels in particular can see UV....

I visited my son an DIL yesterday and they although living in a city have an extended family of Red Shouldered hawks living in their wooded yard. There are 3 generations. An original pair and two years of offspring.

One of this years was found on the ground partially fledged. He is thought to have fallen from the nest and injured himself. He has almost no fear of humans and actually likes to rest on their deck. He brings messy presents of prey in the form of dead birds or rabbits or squirrels. He is thought to be retarded because he hangs around all the time and squeals his hawk squeal constnantly.......hours at a time. He gets up early too.

To bring the thread current, he would fly into their picture window looking out on the deck. He messed it up pretty good.He did it a lot. Hence retarded as in he wouldn't learn.

Any way, they bought some plastic maple leaves that stick to the window. They emit ultraviolet that looks clear to the human eye. Under certain conditions when viewed from outside they are faintly purple. They stopped the flights into the window immediately!!

[Lazamataz]

Also, birds without sexual dimorphism (i.e. you can't tell male from female visually)

[onedoug]

Reproduction and the eye: no evolution there.

[saleman]

You dirty dog ya. You included "evolution" in the title just to get a bunch of hits, didn't you?

I'll be checking in regularly just to view the carnage.

[poindexter]

What does a bird see?

[TX Bluebonnet]

Verrry interesting. Bookmark for later

[1Old Pro]

This explains alot, animals can see the UV but bad drivers can't see other S UV's