Claim CB732:
Amphibians and mammals both have five-fingered hands, supposedly homologous structures indicating common descent. However, they develop in completely different ways. In humans, the limb tip (called the apical ectodermal ridge, AER) thickens, and then programmed cell death divides the AER into five regions that develop into digits. In frogs, the digits grow outward from the beginning.Source:
Sarfati, Jonathan, 2002. Ostrich eggs break dino-to-bird theory.
Creation 25(1): 34-35.
http://www.answersingenesis.org/docs2002/0822_ostrich_dino.asp
Response:
- Frogs and mammals (and other tetrapods) use the same mechanisms of limb develpment, including the same HOX genes and the same molecules. All (except a few highly derived frog species) have an AER. The difference between humans and frog is that frogs have webbed feet. Human-like programmed cell death would destroy the webbing.
Links:
Myers, P. Z., 2004. Digit numbering and limb development. http://pharyngula.org/index/weblog/comments/digit_numbering_and_limb_development/created 2004-9-17