Genetic drift and natural selection are two important ways that evolution happens. But they work in different ways.

Genetic Drift

• What It Is: Genetic drift is when random changes happen in the gene pool of a population, especially if the population is small.
• Example: Picture a tiny island with just a few rabbits. If a storm comes and wipes out most of them, and only a couple of mostly brown rabbits survive, then their babies might end up being mostly brown, too. This happens just by chance.

Natural Selection

• What It Is: Natural selection is when living things that are better suited to their surroundings survive longer and have more babies.
• Example: Think of a group of beetles. If the green beetles are easier for birds to see, they might get eaten more quickly. On the other hand, brown beetles may hide better and live longer, having more baby beetles.

In simple terms, genetic drift happens randomly, while natural selection is influenced by the environment. This leads to different effects on the gene pools of different populations.