Customer Reviews

The New Evolutionary Timetable

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Steven M. Stanley (born 1941) is an American paleontologist and evolutionary biologist at the University of Hawaii at Manoa, who is probably best known for his empirical research documenting the evolutionary process of punctuated equilibrium in the fossil record.

He states in the Preface to this 1981 book, "What I describe in this book is evidence that evolution is not quite what nearly all of us thought it to be a decade or two ago. This evidence comes largely from the record of fossils---a record that until recently was not well scaled against absolute time. The record now reveals that species typically survive for a hundred thousand generations, or even a million or more, without evolving very much. We seem forced to conclude that most evolutionary divergence takes place rapidly, when species come into being by the evolutionary divergence of small populations from parent species. After their origins, most species undergo little evolution before becoming extinct.... This book is not designed to build a rigorous case for the punctuational model of evolution---the goal of my more technical volume, Macroevolution: Pattern and Process, published in 1979. Rather, in the present book I attempt to give the interested non-specialist access to the punctuational view and its implications."

He defines the punctuational view as follows: "the punctuational model asserts that most change is associated with speciation that involves small populations." (pg. 78) "Example after example strengthens the case that rapid evolution is restricted to small populations. For large populations of the sort that constitute the species living all around us today, sluggish change is the norm--much more sluggish change than all but a few modern biologists have envisioned." (pg. 101)

He argues, "Darwin had made elaborate claims that fossil data were too sparse ever to support his gradualistic scheme, yet his condemnation was not based on objective obervation ... Darwin had deduced the incomplete nature of the fossil record from his theory." (pg. 105)