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Re: Back-evolution of limbs.



Larry Dunn wrote (responding to me):
>>         Umm... aren't Reptilia, Mammalia and Pisces classes, according to
>> traditional taxonomy?
>Umm... and aren't phyla aggregates of classes?  So wouldn't a
>comparison of traits of fish and certain mammals be comparisons
>spanning an entire phylum?
        Oops, misread your original post. I thought you were talking about
*between* phyla, not within phyla. Serves me right for tuning out. My
apologies. The lure of the soap box distracted me. :)

>Anyway.  What's your point?  Do you think that fish fins and seal
>flippers have anything to tell us in this discussion of the
>dinosaur/bird nexus?
        Hmm... It depends on what you are talking about. If you are talking
about reversal of locomotor mode, then yes, they do have something to tell
us. If you are talking about the adaptations of cursorial theropods, then
no. The relative Linnean rank of the groups, however, cannot in itself tell
you when a comparison is important or not.

>How about insect wings and bird wings?  Hey, they're both in the same
>Kingdom.  That might shed new light.
        It might just at that, and you know it. It is very likely that these
two features developed homoplastically. However, comparison of their
structures and functions may give clues to the evolution of flight, and
flight-related selection pressures.
        :)
        Wagner
----------------------------------------------------------------------------
    Jonathan R. Wagner, Dept. of Geosciences, TTU, Lubbock, TX 79409-1053
                    "...To fight legends." - Kosh Naranek