Dr. Paul Sereno - Interesting Comments On Dinosaur Evolution
One of the lunch hour symposia at the February 2002 annual meeting for the American Association for the Advancement of Science (AAAS) offered an interesting comment with regard to dinosaur evolution. The big story that captivated the audience was in regard to recent dinosaurs fossil finds in Africa. Remarkable finds have come out of the work of Dr. Paul Sereno and his graduate students at the University of Chicago. He notes that until recently Africa was relatively silent on such fossil information. Even the mammalian fossil record is near nonexistent simply because the continent remains unexplored.
Two of the many comments that seemed to stand out like neon signs are: 1) dinosaurs appear to repeatedly lose digits (e.g., like disappearing fingers) progressively in the fossil record, and 2) even those dinosaurs that obviously lived by and hunted in water never show adaptations to being in water.
But why?
Isn't evolution driven by randomness and adaptations that offer advantages to survival. If in water, then why not adaptations to take advantage of the water niche. This is noteworthy in light of other observations we see in the Science Area of WindowView, especially with regard to a possible nonrandom mechanism for evolution.
Perhaps some evolution is driven by environment, but so too, there may be an information base (like an endowment from a prior historical start point) within a species to represent the potential of all adaptational changes that the species can express. All future changes are based only on this information. All other mutations cause loss.
Could it be that dinosaurs were simply not provided that potential and not the information base so we see only a loss of digits over time, never new ones arising... and life in water, but no adaptations in form, skeleton, or otherwise to indicate evolution in the classical sense. The observations here seem to echo Dr. Spetner's comments that mutations cause only the loss of information. Is the loss of digits a result of what mutations can do?
Dr. Sereno also made another comment on finding a rather large dinosaur skeleton with feathers. The implication is that dinosaurs are predecessors to birds. But the creature as depicted at the symposium was much larger than is reasonable for a flying animal. The suggestion was that feathers afforded shade or cooling, but not flight. What is not mentioned is that feathers appear fully formed in the fossil record. No intermediate forms—from primitive to complex feather morphology—have been discovered.
Dr. Sereno offered yet another example of a feature that is a long way from a connection to flight or from dinosaurs to birds. There may be several reasons for this, but for now we'll simply say several interesting and wonderful new fossil specimens now reside in museums.
(090103)
