OPINION:
THE GREATEST SHOW ON EARTH: THE EVIDENCE FOR EVOLUTION
By Richard Dawkins
Free Press, $30, 480 pages
Just re-released in paperback is Richard Dawkins’ latest book, “The Greatest Show on Earth: The Evidence for Evolution.” As expected from one of the world’s leading science writers, educators and popular defenders of neo-Darwinian evolution, the book is a lucid, well-argued case for the existence of a grand evolutionary past for all matter, especially the living kind. Not only an engaging read, the book is beautifully supplemented from its vibrant cover to its spectacular color inserts.
From the onset, Mr. Dawkins points out the disheartening condition that so many people are confused by what the modern theory of evolution entails. Many will argue, for instance, that “evolution is just a theory,” without realizing that as a scientific term, “theory” means in essence a “verified hypothesis,” not the vernacular “educated guess,” which better defines a hypothesis.
In addition, many still believe that evolution espouses the idea that humans “evolved from apes.” Although some popular publications may incite this idea, evolution claims only an ancestor in the very distant past common to both humans and certain apes.
Many believe that evolution simply involves “blind chance” and long time periods working on inert materials; and, therefore, as an explanatory power for the existence of life’s complexity, the theory of evolution is seriously inadequate from a probability perspective.
However, Mr. Dawkins asserts that evolution is more than blind chance as he discusses many of the projects under way involving intricate computer simulations that appear to confirm reasonable chances for the occurrence of meaningful evolution. (A cogent counterargument to the results of these simulations can be found in “Signature in the Cell: DNA and the Evidence for Intelligent Design” by Stephen C. Meyer, which I reviewed previously.)
In addition, regarding biology, evolution involves a “systematic increase or decrease in a gene’s frequency” in a gene pool. This up-or-down change can be initiated randomly by mutations that “constitute the raw material for evolution by non-random selection.” Coupled with adaptation to the environment over many generations, new species can emerge.
As Mr. Dawkins elaborates, this “natural selection” process was demonstrated in a novel laboratory experiment by Michigan State University researchers Richard Lenski and colleagues. In 1994, Mr. Lenski and Michael Travisano published a report on their work that addressed a “10,000 generation experiment with bacterial populations.” Subsequent experiments are still in progress and have surpassed 50,000 generations.
The experimental results of these studies (along with other key examples given in the book) clearly show reasonable mechanisms for species modification for what has been called “micro-evolution.” But, how strongly do the studies conclusively demonstrate experimental evidence for evolution at a more advanced level, or “macro-evolution”? Here’s where micro-evolution - as a demonstrable fact that everyone seems to agree is real - gets confused with macro-evolution - the level of evolution (certainly beyond the genus taxon) with which many take issue.
From the Lenski and Travisano reference, Mr. Dawkins takes graphs that display increases in cell volume and relative fitness through 10,000 generations. But the graphed data seem to be converging on a limit. In other words, changes do not continue indefinitely. And, even a population density graph that shows an abrupt, significant increase and subsequent leveling-off at a new, higher population value after 33,000 generations does not necessitate the conclusion that macroevolution is inevitable.
In fact, the data interpreted rigorously only support ecological specialization and subsequent survival of the species rather than providing substantial evidence for the arrival of a new species.
Nonetheless, Mr. Lenski’s experiments aside, consistent with other front-line defenders of evolution, Mr. Dawkins essentially marshals the voluminous data from micro-evolution research and observations to “extrapolate backwards,” and, with the help of inference from the fossil record, makes the case for macro-evolution. This approach, although necessary, leaves too much room for “hand-waving arguments” and “just-so stories” that seem to populate much of the proffered evidence for evolution.
Regardless, fans of Richard Dawkins will not be disappointed by this thoroughgoing volume, while those who shudder at even the thought of evolution can profit from the perspective of this masterful writer and scholar.
As I noted in an earlier book review, I have selected “The Greatest Show on Earth” as one of the course textbooks for a course on “ID and Evolution” that I am teaching this fall. I chose “Signature in the Cell” for the intelligent design rationale in this course.
Anthony J. Sadar is a certified consulting meteorologist and principal author of “Environmental Risk Communication: Principles and Practices for Industry” (CRC Press/Lewis Publishers, 2000).
Please read our comment policy before commenting.