Photo courtesy Shutterstock. There are four basic mechanisms by which biological evolution takes place. These include mutation, migration, genetic drift, and natural selection. Each of these four mechanisms are capable of altering the frequencies of genes in a population and as a result, they all are capable of driving descent with modification.

EARLY THEORIES OF EVOLUTION: 17th-19th Century Discoveries that Led to the Acceptance of Biological Evolution

Through the process of descent with modification, the common ancestor of life on Earth gave rise to the fantastic diversity that we see documented in the fossil record and around us today. Evolution means that we're all distant cousins: humans and oak trees, hummingbirds and whales.