The Emergence of Whales
“The Emergence of Whales: Evolutionary Patterns in the Origins of the Cetacea” (Advances in Vertebrate Paleontology) edited by J.G.M. Thewissen. Plenum Press, ISBN 0306458535.
“Reviewer’s Note: The following summaries were initially prepared to allow discussion of current scientific understanding of the evolution of cetaceans for an informal Internet (Usenet) discussion group. As such, they are ONLY summaries and do not accurately reflect the detailed research effort and knowledge of the primary authors. The summaries are incomplete and were not intended to be comprehensive. The best information on each of these topics will be found in the book referenced above, which also contains detailed diagrams and figures that were not reproduced.Foreword:
What I’m going to attempt is to summarize what’s in each chapter. I’m going to be more successful in some cases than others: the genetic mapping stuff is pretty dense for someone outside the field. The book has some remarkably intricate diagrams that I can’t hope to reproduce, and has thick jargon everywhere. Here’s a gem from Chapter 6:
“Paraxonia is diagnosed by nine unequivocal synapomorphies: 1) stylomastoid foramen encircled ventromedially by tympanic bulla (character 8); 2) presence of sigmoid process (14); 3) absence of a lacrimal tubercle on the orbital rim (41); 4) entepicondyle of humerus 25% or less than the width of the ulnar and radial articulation surface (64); 5) paraxonic foot (75); 6) four functional digits of the foot (76); 7) elongate blastocyst (78); 8) penis erection via relaxation of retractor muscle with little cavernous tissue (79); and 9) three primary bronchii(80).”I’m fairly sure what 6 and 8 are about 😉 Chapter 6 is also a very interesting chapter, at least what I could understand.
SO, what I’m hoping that this will accomplish is to show the depth and breadth of research in this field. Most of us tend to learn about subjects outside of our own fields on the periphery; media news reports at one level, popular press science magazines at another. Thus we learn about the “big news”, but not the day-to-day detailed effort of researchers, most of whom rarely ever think about the hue and cry of the creationism/ evolution social debate.
What’s clear in this book is that evolution is a given; the animals that are represented by these fossils are somehow related to each other. If they weren’t, there wouldn’t be any point in these people doing what they are doing. Because of that, “proving” that evolution happened, or that natural selection is the process by which evolution occurred, is certainly not the main purpose of these papers. So the authors make statements that are tantalizingly close to stating how this evidence relates to the underlying reality:
“Characteristics of archaeocetes such as body mass, tooth size, auditory bulla size, femur length, and relative brain size are documented in Figs. 7-9, which are related to progressive trophic, auditory, cognitive, and life history adaptation to life in the sea.”As this “series” goes on, I’ll examine where natural selection is implied as the mechanism that led to adaptations such as those described above (and much more). You have to look closely for it.
This page was last updated September 1, 2001.