Things I learned while reading “Dinosaur Heresies,” by Dr. Robert T. Bakker: pp. 393-462. Part 5
Dr. Bakker discussed punctuated equilibrium and made the point that warm blooded critters undergo more adaptive radiation (than cold-blooded) and that a family of mammals may last 25 million years as compared to a cold-blooded reptilian family, which may remain stable for 55 million years (Bakker 404-405). He said that warm-blooded animals, being more competitive, displace one another at a more rapid rate than the more lethargic animals, thus resulting in the adaptive radiation pattern. The crocodilians, cold-blood reptiles have remained stable for 100 million years in the fossil record. Lethargic animals are resistant to drought or famine due to their low metabolisms. This has contributed to the long-lived crocodile tribe over time. Bakker suggested that dinosaurs did not survive the Cretaceous extinction because they were hot-blooded.
Another piece of evidence for warm-blooded dinosaurs was the presence of warm-blooded protomammals prior to the rise of the dinosaurs. Bakker reasoned that it would make no sense to begin a warm-blooded “flash” of protomammals immediately followed by a cold-blooded dominance of dinosaurs (Bakker 424). This would represent an evolutionary throwback and fail to show a uniform progression toward warm-blood dominance.
On page 428, Bakker discussed that there have been eight major extinction events that influenced the large land animals and that the last event happened about 10,000 years ago.
On page 430, Bakker provided a neat chart showing how that the long neck marine “swan lizards” were deep sea creatures and that the eel-like Cretaceous whales such as the Basilosaur and the smaller whales such as Zygorhiza (with fossils currently found in current day Mississippi and Alabama) were found in the shallow marine habitats. These marine shallow ocean whales thrived in the warm seas that bisected the United States at that time.
Bakker discussed possible extinction events that led to mass dinosaur extinction at the end of the Cretaceous period. This is interesting to me since I spend time at the W.M. Browning Cretaceous fossil park in North Mississippi hunting shark tooth fossils. A possible mechanism for Cretaceous extinction: climate change. Bakker seemed to allude to some type of “climate change” which dried up the shallow oceans, thus prohibiting aqueous habitat for many warm water-loving marine animals. Land bridges formed which linked continents and produced intercontinental competition between new species and introduction of new diseases (Bakker 442-443). On page 444, Bakker referred to this phenomenon extinction event as “nature’s own pulse,” simply a cycle of the planet.
On page 447, Bakker discussed an Ur-dinosaur, a “very primitive ancestor.” In my blogged reflections on “Dinosaur Heresies,” part 4, I asked: “What is an Ur-amphibian?” From what I can tell, the “Ur-” prefix is the ancestral primitive relative of downstream critters in a phylogenetic tree.
On page 449, Doctor Bakker discussed how that scientists, in their zeal to complete their theory of the “spoked evolutionary hub,” began inventing imaginary groups to fit the empty spot(s) and used only pieces of skeletal remains to act as models to fit the existing theories.
My reflection: This does not sound like good science. It is OK to not know the answer(s). There are many things that will be “understood better by-and-by.” I believe the tendency to “plug the holes” is a human thing. This leads me to my next reflection: On pages 395-397, Bakker discussed the “beat-down” the religious community received at the hands of the evolutionist, Charles Darwin. On page 397, he talked about how “the fossil record” basically is the answer, the unbiased judge. Here lies a problem: If the fossil record is the answer, then it is difficult to accept scientists who use tenuous tidbits of physical fossil evidence to act as proofs to their theories. Once again, it is OK to say that you don’t understand. Us religious folks don’t understand everything, and we live by faith. Maybe a bit more of “live and let live” is in order.
Finally, Dr. Bakker spent time considering the classification of dinosaurs and completed his work with an exclamation that birds are living dinosaurs.
Bakker, Robert T. The Dinosaur Heresies. William Morrow and Company, Inc., 1986.