In terms of Darwinian evolution, it’s become common to accept his two precepts: 1) life evolves from common ancestors, and 2) it evolves by means of natural selection and adaptation.
This, however, doesn’t necessarily seem to be the case.
Adaptationism certainly appears to hold true in microevolution – small-scale evolutionary change within species, such as changes in beak shape in Galapagos finches in response to available food sources.
However, there is still huge debate about the role of natural selection and adaptation in “macroevolution” – big evolutionary events such as changes in biodiversity over time, evolutionary radiations and, of course, the origin of species. Are these the cumulative outcome of the same processes that drive microevolution, or does macroevolution have its own distinct processes and patterns?
After reading the essay by paleobiologist Keith Bennett, it’s quite obvious that evolution is way more complex than they taught in high school or college.