I've just finished watching this evenings Horizon on BBC2. The
subject was the changing views on the vertebrate move from water to
land - and the new evidence that has come to light over the last ten
years. Until relatively recently all we had was a very good
candidate for the fish end of the transition - Eusthenopteron and one
fossil of a very early tetrapod - Icthyostega. Recently more fossils
of Devonian tetrapods, such as Acanthostega have been found.
The most important points were :
1. The pentadactyl (five-fingered) limb appears after the transition.
The earliest tetrapods had more toes.
2. Legs developed for movement in WATER - probably for moving amongst
the abundant plants. The earliest tetrapods have gills and legs that
angled wrongly for walking on land.
3. Very recently an obscure fossil was reexamined. It was a section
of jaw which turned out to be morphologically intermediate between
fish and tetrapods. Even though it is likely to be a side-branch
rather than a direct ancestor of ours it is the first fossil showing
this particular transition. (Although the indirect evidence strongly
supported the relationship).
Duane Gish appeared on the program although I doubt that he will be
very pleased with it. He was only shown to emphasise that there are
people who will exploit the lack of fossils to try to suppress
evolution. Gish played no part in the main story. It would have
been interesting to see his reaction on being told that a new
transitional fossil had been found but I doubt that it would have
made good television.
"The T'ang emperors were strong believers in the pills of
immortality. More emperors died of poisoning from ingesting minerals
in the T'ang than in any other dynasty" - Eva Wong _The Shambhala
Guide to Taoism_