How do genetic mutations contribute to evolution?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

A vertical geologic time scale chart spanning from 650 million years ago to the present, with colored bands for each era and period. Illustrations and labels highlight key evolutionary events such as the appearance of skeletal elements, first fishes, land plants, amphibians, reptiles, dinosaurs, mammals, and humans. — evolution The geologic time scale from 650 million years ago to the present, showing major evolutionary events.

Genetic mutations are the primary source of genetic variation, which is essential for evolution by natural selection. These mutations are permanent alterations in an organism's genetic material, occurring randomly in DNA sequences. They can arise spontaneously due to errors in DNA replication or be induced by environmental factors like radiation or chemicals.1234

Mutations can be small, affecting a few nucleotides (gene mutations), or large, impacting chromosome structure or number (chromosomal mutations). While most mutations are neutral or harmful, some can be beneficial in specific environments. These beneficial mutations provide the raw material for evolution, allowing populations to adapt to changing conditions over time.125