An evolutionary biologist disputes the hegemonic theory of how animals have populated the planet, challenging prevailing assumptions about the time frame in which species separations necessarily occurred.
De Queiroz suggests that in many instances, species, migration has occurred much more recently than has been commonly accepted. He and his associates have taken advantage of modern methods of genetic sequencing to improve on previous estimates. They have refined the notion of a molecular clock—previously dependent on retrieving DNA from fossils and correlating this with geological evidence—to determine the evolution of new species more accurately by estimating the rate of mutation separating the genomes of presently related species. He cites his own studies of related species of garter snakes and similar research on monkeys, which indicate that they evolved over a much shorter time span. At the time, when these land-based species began to evolve independently (presumably because their habitats had diverged), there were no continental connections, such as land bridges, to account for their migrations. The author collected garter snakes from two species found on opposite sides of the wide Sea of Cortez. After sequencing their mitochondrial genes, he determined that they would have separated approximately a few hundred thousand years ago rather than the generally accepted estimate of 4 million years ago. Therefore, he suggests—judging by ocean currents and winds—that one or more snakes must have traveled from the mainland over a 120-mile sea by clinging to a naturally formed raft. Other recent genetic studies of two similar monkey species lend credibility to the author’s unlikely hypothesis that such ocean crossings can account for long-distance colonization, despite the statistical improbability. De Queiroz disputes scientific theories based on outdated evidence and offers an in-depth critique of intelligent design.
An intriguing window into the ongoing academic debate about evolution.