Xref: utzoo sci.bio:5105 talk.origins:15527
Newsgroups: sci.bio,talk.origins
Path: utzoo!utgpu!lamoran
From: lamoran@gpu.utcs.utoronto.ca (L.A. Moran)
Subject: Coelacanth and evolution
Message-ID: <1991Jun4.164709.431@gpu.utcs.utoronto.ca>
Organization: UTCS Public Access
Date: Tue, 4 Jun 1991 16:47:09 GMT


Darrin Sharp asks,

       "I know that outwardly, the live specimens (of lungfish) very
        closely resemble the 400 million year old fossils. But how can 
        this be? Is it common for organisms to not evolve for 400 million
        years? How long has it been since sharks and alligators/turtles/
        crocodiles evolved? Any other species that haven't changed in this 
        long?"

There are no known examples of species that have not evolved for any 
substantial period of time and this includes coelacanths or lungfish. It is
true that the external morphology of these animals closely resembles that of
organisms that lived about 60 million years ago. However, at the molecular
level these lungfish have evolved as much as any other extant organism.
There is no such thing as a living fossil.

It is a common misconception among non-biologists that evolution is associated
with morphological change. Such a misconception is fostered by the fossil
evidence that emphasizes such change. 

Incidently, I believe that the modern lungfish (Latimeria) has anatomical
features that are different from those of the extinct organisms. Thus it is
not even correct to claim that there has been no morphological change.


-Larry Moran