How Continental Drift Affects Evolution
Though taken for granted by most people today, the idea that the continents move across the
Earth’s surface relative to each other was dismissed as impossible or ridiculous only 60 years
ago by most geologists just as evolution was dismissed in the same way by most biologists a
century earlier.
In both cases, the reason for the previous dismissal of both ideas was the lack of a credible
physical mechanism for both theories. In the case of evolution, Darwin supplied the mechanism
in the form of natural selection. In the case of continental drift, the mechanism for it was plate
tectonics, which was not proposed until the 1960s. Prior to that decade, books describing the
history of life on Earth would often show land bridges connecting continents like Africa and
South America in earlier time periods, such as the time the dinosaurs existed. They did so
because the fossil record showed the same land animals on both continents, indicating that they
were connected. Land bridges did exist between North America and Asia in prehistoric times,
and today between North and South America, but the land bridges between Africa and South
America, between North America and Europe, and between other continents appeared to stretch
across present day oceans to connect continents at their present day positions. These depictions
were not only unscientific, they were downright ridiculous, for aside from the fossil evidence,
there was not a shred of evidence those extra-long land bridges had ever existed. They were a
product of dogmatic thinking that was misapplied to geology. Once plate tectonics was proposed
and accepted, and enough evidence for that theory supported it beyond a reasonable doubt, the
fossil evidence made far better sense.
The movement of continents has had a profound influence on how land animals evolved.
1. If two continents split, the populations of animals on both evolve in different directions
than they would have had they stayed a single population.
2. If two continents collide or form a land bridge between them, the two different
populations of animals on those lands begin to mix. Sometimes, that results in extinctions
of many species of one population by competition with members of the other population.
3. A continent moving up or down a series of latitudes along the Earth exposes the
population of animals on it to constantly changing environments, resulting in much faster
evolution than there would be if the continent moved along the same latitudes.
Charles Darwin and his supporters supplied one critical element, evolution, to explain the history
of life on Earth, and Alfred Wegner and his successors supplied the other, continental drift. And
one is profoundly affected by the other, and the other gives support to the first.
Curiously, Creationists have less of a problem with continental drift than they do with evolution.
The reason seems to be a possible reference to continental drift in the book of Genesis. In chapter
10, verse 25, it is written that Eber had two sons, the first being named Peleg,
meaning“division”, because in Eber’s lifetime the Earth was divided. This is assumed to be the
splitting up of the ancient supercontinent of Pangea. But the movement of the continents of such
a magnitude over a few hundred or thousand years would involve far more force than one could
plausibly account for. The most powerful and destructive earthquakes and volcanic eruptions,
ruining entire cities, result from movements of the continents of only a few meters at a time. Plus
the fact that the movements of the continents involved much more than just the breakup of
Pangea.