Natural Selection & Evolution

"Survival of the fittest" doesn't mean strongest

The phrase "survival of the fittest" is often misunderstood. "Fittest" here means best fitted to the environment, not strongest, fastest, or most aggressive. A small camouflaged moth can be "fitter" than a large showy one if it survives to reproduce while the showy moth gets eaten.

Individuals don't evolve

A single rabbit cannot evolve in its lifetime. Its genes are fixed at conception. Populations evolve over many generations as the mix of alleles in the population changes.

Mutations are random, but selection is not

Mutations happen randomly with no regard for what would be useful. The vast majority are neutral or harmful. Natural selection, however, is not random: it consistently favours individuals with traits that help them survive and reproduce. So evolution combines random mutation with non-random selection.

Evolution does not have a goal

Evolution is not "trying" to produce humans, or any particular outcome. It simply favours whatever variants happen to survive and reproduce best in the current environment. If conditions change, evolution can move in the opposite direction (as with peppered moths becoming pale again after the Clean Air Act).

Acquired characteristics are not inherited

A bodybuilder's muscle growth is not passed to their children. A skill learned during life (speaking a language, playing piano) is not encoded in DNA. Only genetic changes are inherited. This was an old idea (called Lamarckism) that was disproved when DNA was discovered.

Humans did not evolve from monkeys

Humans and modern monkeys share a common ancestor, but humans did not evolve from any species alive today. Modern chimpanzees, gorillas and humans are all descended from a single ape-like ancestor that lived about 8 to 10 million years ago, and have evolved separately ever since.