What term describes the process of change in species over time?

Evolution is the process by which inherited characteristics in populations change over time. Across many generations, these changes can produce new adaptations, new species, and the enormous diversity of life on Earth.

Evolution occurs in populations rather than in individual organisms. Genetic variation arises through processes such as mutation and recombination, while natural selection can increase traits that improve survival or reproduction in a particular environment. Other forces, including genetic drift and gene flow, also change populations.

Natural selection is therefore not a synonym for evolution. It is one mechanism that can drive evolutionary change. Mutation creates new genetic variants, but mutations are not automatically beneficial; their effects depend on the organism and its surroundings. Adaptation describes a trait or process that improves fitness, not the entire history of biological change.

Charles Darwin and Alfred Russel Wallace helped establish natural selection as a major explanation for evolution. Later discoveries in genetics, especially the rediscovery and development of Mendel’s work, joined heredity with Darwin’s ideas to form the modern evolutionary synthesis. In biology, evolution explains both the shared features of living things and their differences.