Claim CB751:
If one eye mutates into existence, then the animal would have just one
eye, not two. The same goes for arms, feet, ears, wings, and so forth.
Evolution says these body parts should arise one at a time, yet most
animals have bilateral symmetry. We do not find one-flippered dolphins or
one-eared ape-men.
Source:
Pinkoski, Jim. 1993. A Creationist's View of Dinosaurs and the
Theory of Evolution. Amazing Facts, Inc., Roseville, CA.
Response:
- Eyes, legs, and all the rest are not evolved anew in each animal.
Bilateral symmetry evolved more than five hundred million years ago.
Animals since then have inherited that symmetry.
- Bilateral symmetry is implemented by signalling molecules that give
identical domains on left and right. A person's left eye (normally) is
exposed to the same development signals as their right eye, so the two
eyes grow alike. A single mutation that varies how an eye develops
would still affect both eyes equally. For asymmetrical eyes, an
additional mechanism must evolve to supercede the symmetry and give
different development signals to each side.
Links:
Myers, P. Z. 2005 (12 June). Pinkoski again: How stupid can creationism
get? http://pharyngula.org/index/weblog/comments/pinkoski_again/
Further Reading:
Carroll, Sean B. 2005. Endless Forms Most Beautiful. New York: W. W.
Norton.
created 2005-6-18
