Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!mnetor!seismo!lll-lcc!ames!ucbcad!ucbvax!jade!violet.berkeley.edu!dean From: dean@violet.berkeley.edu (Dean Pentcheff) Newsgroups: sci.bio Subject: Re: The Red Queen (really: Eyeless fishes) Message-ID: <2103@jade.BERKELEY.EDU> Date: Wed, 7-Jan-87 01:30:48 EST Article-I.D.: jade.2103 Posted: Wed Jan 7 01:30:48 1987 Date-Received: Wed, 7-Jan-87 18:42:58 EST References: <741@aecom.UUCP> <927@husc6.UUCP> <124@bcsaic.UUCP> Sender: usenet@jade.BERKELEY.EDU Reply-To: dean@violet.berkeley.edu (Dean Pentcheff) Followup-To: sci.bio Distribution: na Organization: University of California, Berkeley Department of Zoology Lines: 21 Summary: polyphyletic origin (?) implies advantage? In article <124@bcsaic.UUCP> michaelm@bcsaic.UUCP (Michael Maxwell) writes: >I suggested this [genetic drift] in answer to an exam question once, as >the origin of blind >(eyeless) cave fish. (The incidence of eyeless fish is quite high, but for >obvious reasons the eyeless ones seldom make it very far in life up here.) >The professor didn't like my answer...his point was that there had to be a >selective advantage to blindness in cave life. I didn't believe so at the >time, and I'm still skeptical. Anyone care to comment? I'm not sure, but I suspect that eyelessness in cave fish arose independently from several groups of (eye-bearing) fish. If this is the case, it seems unlikely that cave fish stemming from different ancestral groups would share the _same_ trait due to drift, given that there are only a few characters that tend to be different in cave fish (lack of eyes, lack of pigment). If, on the other hand, the trait conferred a selective advantage, then its appearance in several groups is reasonable. The advantage (presumably) has something to do with energy savings for the eyeless fish (though this is a rampantly "selectionist" argument). -Dean (dean@violet.berkeley.edu)