Punctuated Equilibria - One Step Beyond

This review will present my comments about one of the best books concerning evolution that I can remember reading. The reasons for this profound statement will be presented below.

The book is called Sudden Origins, Fossils, Genes, and the Emergence of Species by Jeffrey H. Schwartz. John Wiley and Sons published this work in hardcover in 1999. The retail price of Sudden Origins is $27.95. The 420 pages of the book, printed in what I would estimate to be 10-point type, makes it literally packed with information. Sudden Origins is well worth your reading time so don't be turned away because of its length.

Jeffrey Schwartz is an anthropology professor at the University of Pittsburgh. Other books to his credit include What the Bones Tell Us and The Red Ape. According to information on the dust jacket, Schwartz is a coauthor with Ian Tattersall of an upcoming three volume work: The Human Fossil Record.

Now, why am I so excited about Sudden Origins? I have many reasons for my opening statement and I will explain myself to some degree before telling you any of the substance of the book. Firstly, Sudden Origins is written so that most people will have no trouble reading and understanding the ideas that Schwartz presents. This is not to say that there are no difficult words or concepts - but there certainly are. This brings me to my next words of praise: Schwartz explains all concepts and important technical words as he presents them. In addition, for people like me who may not remember all of this, he has included a glossary of terms. This in itself is extremely important for readers who are not very familiar with the terms of genetics. Beyond this, Sudden Origins will impress the reader with how closely linked all life forms on this planet really are. Lastly and perhaps most important, Schwartz presents new ideas concerning the mechanisms of the evolutionary process that seem to tie up loose ends left by others. Sudden Origins is fascinating.

It is not necessary for me to review each of the twelve chapters in Sudden Origins in detail since much of the book involves the history of evolutionary theories. The author's theories are not presented until the last chapter. Sudden Origins, like so much in life sciences, builds on the work of previous scholars. Schwartz takes considerable time to present and interpret the ideas of earlier evolutionists in historical context. The stories, proofs, and refinements in theories progress through history as scholars learned more and more about biology and inheritance. This information is not a mere statement of historical facts but integral background that leads the reader logically toward Schwartz's final proposal.

One of the intriguing chapters was "Humans as Embryos." No, this isn't about human embryos. In simplified terms, adult humans are presented as morphologically grown up children. The scientific word used to describe this phenomenon is "neoteny." This phenomena can apply to any living organism and not just humans. What neoteny means, using humans as the example, is that as developing animals, humans "prolong the rate at which they mature physically relative to the time it takes to become reproductively mature." Physical maturation ceases once sexual maturity is reached (an animal may grow larger but its physical proportions stop changing).

You have probably heard that humans are genetically most closely related to chimpanzees. We have 98% of the same genes as chimps. So why do we look so differently from them? This involves neoteny and concerns what genes do and how they work. You will learn that some genes control specific parts of an organism (structural genes). What you may not know is that other genes control the timing of when these structural genes "turn on" and "turn off" (regulatory or homeobox genes). This knowledge comes from much of the more recent work in genetics that Schwartz describes in this chapter. The regulatory gene function has inspired and provided Schwartz with the means to formulate a mechanism for the process of speciation.

Schwartz has taken the principles of heredity from earlier workers including Darwin (Natural Selection); Mendel (inheritance); Ernst Mayer (an ornithologist), George Gaylord Simpson (a paleontologist), and Theodosius Dobzhansky (a geneticist), et. al., in the modern "Synthesis" of evolution (the principles of modern genetics); Niles Eldridge and Stephen Jay Gould (Punctuated Equilibria); and new findings about regulatory genes to formulate a more complete idea of how evolution works.

I was surprised to find that earlier theories of evolution presented ideas proposing how an individual's morphology could change from parents to offspring but fell short of providing any workable theory to explain how an entire species could change. Most geneticists favored a gradual change caused by the slow accumulation of small changes through minor mutations over long periods of time. This makes any worthwhile contribution from paleontology useless toward evolutionary theory because evidence of such a slow gradual change is missing from the fossil record (the infamous gaps in the fossil record preclude showing gradual change). This presents a problem - how does a mutation in one individual work its way into a whole population? Think about it. Let's say that there was a genetic mutation in your family that caused you to have much longer limbs than your parents. Does this make you a new species? No. Will this mutation affect any other humans in the world? No. It would seem that all previous theories could come up with ways to change an individual from generation to generation but could not provide the jump to a speciation event. Geneticists basically brushed this objection aside believing that their gradual mutation theory was sufficient to explain everything.

Sudden Origins provides a neat package, if you will, that ties together all of the knowledge gained over the last two centuries and bundles it into a logical theory. Schwartz proposes sudden speciation events as did Eldridge and Gould but advances the genetic mechanism to make the theory complete. Besides making our knowledge of heredity and genetics fit smoothly in his theory, Schwartz has also made the case for Punctuated Equilibria. He has made the infamous "gaps" in the fossil record disappear as imperfections. And, he has provided the answer to phenomena previously impossible to explain including the often cited question: "How is evolution possible if you can't explain how an eyeless creature ‘transforms' into a creature with fully functional eyes?" It will be interesting to see how the scientific community responds to Schwartz's theory.

Although Sudden Origins addresses evolution of life forms in general, human evolution is brought up in the beginning chapters. Since the book is organized chronologically, it is not reintroduced until the last chapters. I hope that by this time not too many of my readers believe that Charles Darwin invented evolution or that "evolution" is a theory. Humans have always wondered about their place in nature. From ancient times up through the Dark Ages, religions had offered explanations for mans place in nature. As men learned more and more about their natural world they began to question the meaning and occurrence of fossils and mans place again. It has been an uphill battle waged by many famous individuals to determine the age of the earth and that the fossil evidence indicated that life on earth has changed over vast periods of time. So, it was this observation of the changes in life forms over time, as seen in the fossil record, coupled with the vast age of the earth that prompted men to theorize how this "evolution" could have happened. Early on, mans place was not questioned since religion had a satisfactory answer and no fossil humans had been discovered. Conflict arose when human-like fossils started to be recovered and were identified as such.

I found Sudden Origins to be an exciting book to read that was logically and thoroughly presented. This is a must read for anyone who has an interest in evolution in general since Schwartz has summarized the work of virtually all evolutionary theorists in one well written volume.

There may be some among those who read this review that question the evidence of evolution and/or the theories proposed for its mechanism. I would suggest that anyone in that position read Sudden Origins. You will find answers to many of your questions within this book.

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