What is the term for a change in the genetic composition of a population over time?

The term that describes a change in the genetic composition of a population over time is evolution. Evolution encompasses the processes through which species undergo genetic changes, leading to variations in traits and adaptations over generations. It can occur due to mechanisms such as natural selection, genetic drift, and gene flow, all of which contribute to the gradual transformation of a population. This continuous change in the genetic makeup may ultimately lead to the development of new species, but the broader concept of change over time within populations is specifically defined as evolution.

In contrast, mutation refers to a change in a single gene or DNA sequence, which can be a source of genetic variation but does not encompass the wider shifts in population genetics. Adaptation is a specific type of evolutionary change where organisms become better suited to their environment, and speciation is the process by which new species arise, often as a result of evolutionary changes. While related to evolution, adaptation and speciation are more specific phenomena within the broader evolutionary framework.