Which term describes the gradual change in a species over time?

The term that describes the gradual change in a species over time is evolution. Evolution refers to the process through which populations of organisms change over generations, primarily driven by mechanisms such as natural selection, genetic drift, and gene flow. This results in adaptations and the formation of new species as they accumulate adaptations to their environments. Evolutionary changes can be small and incremental, leading to significant differences over long periods, which is essential for understanding how diverse life forms have developed and diversified from common ancestors.

Adaptation refers specifically to traits that enhance an organism’s ability to survive and reproduce in its environment, rather than the overall process of change in a species. Mutation involves changes in the genetic material that can lead to variation within a species, but it is just one of the factors that can drive evolutionary change. Variation addresses the diversity of traits within a population but does not encompass the broader process of change over time as a whole. Therefore, evolution is clearly the most appropriate term for this concept.