Evolution - GCSE Biology Definition

Evolution is the process by which different kinds of living things change over time. This happens through small changes in their genes, which are passed on from parents to their offspring. These changes, called mutations, can sometimes help a living thing survive better in its environment. Over long periods, these helpful changes add up, leading to new species forming. Evolution is driven by something called "natural selection," where the organisms that are best suited to their surroundings survive and reproduce. This is why we see such a wide variety of life forms on Earth today.