Path: utzoo!attcan!uunet!lll-winken!lll-tis!helios.ee.lbl.gov!pasteur!ucbvax!bloom-beacon!athena.mit.edu!orwant From: orwant@athena.mit.edu (Jonathan L Orwant) Newsgroups: sci.bio Subject: Evolution Keywords: evolution Message-ID: <5944@bloom-beacon.MIT.EDU> Date: 28 Jun 88 05:03:32 GMT Sender: daemon@bloom-beacon.MIT.EDU Reply-To: orwant@athena.mit.edu (Jonathan L Orwant) Distribution: sci.bio Organization: Massachusetts Institute of Technology Lines: 15 I'm a bit confused about how special-purpose anatomical parts can evolve, e.g. the evolution of a bird's wings from an unwinged predecessor. If it happens gradually, then why isn't the 2% of a wing along the way an evolutionary detriment? I've heard that it acts as a heat insulator; maybe so, but I would think that there would be much more efficient ways of retaining heat that would give competing organisms an advantage in the meantime. Another explanation I have heard is that specialized master-genes turn on entire sequences of genes so that once a mutation triggers the proper master gene, an entire wing appears. If this is the case, where is the information of how to grow a wing stored in an animal whose ancestors were wingless? -Jon Orwant (orwant@wheaties.ai.mit.edu) Pity me. I'm a computer scientist.