n. small-scale changes in the history of life, such as changes in allele frequencies in a population (over a few generations); also known as change at or below the species level.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
n. evolution resulting from small specific genetic changes that can lead to a new subspecies
Word Usage
"The so-called proofs of evolution all refer to microevolution, that is to say, variation within an existing group of plants or animals."