Re: [asa] Extinction/Extant

Bernie asked:

Isn't the lungfish a great example of a "transitional form?" If not, why
> not (a fish with lungs... almost all fish have no lungs)?
>

Actually no. It is not a transitional form. Lungfish and coelocanths are
sometimes referred to as a "living fossil" but that is also deceptive. Both
are recent members of lineages that go back to the Devonian. But like
everything else they have also evolved over that long period of time. They
are not the same as their ancestors.

To find transitional forms that link lobe-finned fish with tetrapods, you
have to go back into the past down the evolutionary tree. As it turns out
there is quite a number of transitional fossil species in the late Devonian
around the time that the first tetrapods appeared. These are the
transitional forms -- not modern species.

A lot of the popular misconceptions about transitional forms are a result of
uniformed media coverage, and some misguided popularization by some
scientists as well.

Keith

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Received on Mon Oct 12 17:44:26 2009