What is the term for changes in allele frequencies within a population over a short period?

The term for changes in allele frequencies within a population over a short period is microevolution. Microevolution refers to small-scale evolutionary changes that occur within a population, often resulting from mechanisms like natural selection, genetic drift, mutation, and gene flow. These changes can lead to variations in traits and adaptations within the population, influencing how it may evolve over time.

Understanding microevolution is crucial as it helps explain the dynamics of populations and can be observed in real-time, such as with populations of organisms experiencing environmental changes. On the other hand, macroevolution encompasses broader evolutionary changes that occur at or above the species level, such as the emergence of new species or major evolutionary trends, which happens over a much longer time frame. Gene drift, while related to genetic changes, typically refers to random changes in allele frequencies, often referring to the broader effects of genetic drift rather than specific changes observed in microevolution. Genetic variation, while important, describes the diversity of alleles within a population rather than the mechanisms driving changes in allele frequencies directly.