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I visited Yale's Peabody Museum today. (This
is a holiday called Presidents' Day, honoring Washington and Lincoln.) As
part of the festivities called Dino Days, teachers had the opportunity to meet
the public.
In a discussion with one teacher, anonymous in
tribute to his sacrifice, he indicated that it is difficult to think of a true
reversal, when a lost anatomical attribute disappears and then reappears.
(This was in context of noting that a flightless bird's arms do not grow into
grasping weapons, but frequently disappear or
retain limited functions from before flight was lost. Not a
BCF'er)
He mentioned as an example the fact that mammals
lost the ability to see color. (How this was determined I forbore asking;
we talked for only about 3 hours, with interruptions, and cladistics was
included.) He said that mammals did not regain this capability as it was
priorly, but instead developed a new mechanism, a 'patch'. (I'm wondering
how mammals 'knew' there were colors to be seen, but that's a different
discussion also.)
Can anyone suggest an example of a true
reversal?
The above quotations are paraphrases, and any
mistakes are mine, of course.
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