Vestigial Organs

[DC10]

Hi Viole

"My favorite is the tail. True, we do not have a tail anymore, but the genes to create the tail are still there and sometimes babies are born with one tail. These genes are just silenced by another gene that disables them. What is the use of the tail-generating genes, if we do not need a tail, anymore?"

Do you know if other apes show this atavism?

[DC10]

viole brings up good examples. I always think about the appendix, though that could have minimal function (as most of this stuff does get re-adapted) surely whatever tiny function it serves is outweighed by the fact that it regularly killed people when it became infected before surgery was available. Evolution isn't terribly efficient as 'designing' stuff, so if it is in the genes to have a certain structure which has been rendered useless, selection pressures are likely to render it with some secondary use, and of course, whatever original structures were involved with it remain to a certain degree, such as in the attachment of the coccyx. The question is not if these structures have *any* use whatsoever, but if they are more likely to have been the result of blind evolutionary processes or the result of direct design.

Or, how about eyes on cave fish that are blind? Hip bones in whales.

A while back I heard the quote "Nothing in Biology makes sense except in the light of evolution". I knew what they were saying but it didn't really sink in until I started studying evolution. The quote is dead on, nothing makes sense in biology EXCEPT in light of evolution.

It's the title of a very thought provoking article by Theodosius Dobzhansky, published in "The American Biology Teacher" in 1973, and reproduced in the excellent collection of articles in "Evolution" edited by Mark Ridley in the Oxford Readers series (nb not to be confused with the same author's textbook of the same name).

In checking this before posting, I was amused to notice the closing comments in Ridley's Summary to the article: "The theory of evolution is established beyond reasonable doubt. Moreover, it does not clash with religious faith."

Hm.