What factors can cause changes in the genetic composition of populations?

• A. Climate change and habitat destruction
• B. Migration, selection, and mutation
• C. Biodiversity and environmental conservation
• D. Reproductive isolation and speciation

Answer: (B)

The genetic composition of populations can be influenced by several key factors, particularly migration, selection, and mutation.

Migration refers to the movement of individuals into or out of a population, which can introduce new alleles (gene variants) or remove existing ones, thereby altering the genetic makeup. This process can enhance genetic diversity or shift allele frequencies in a population.

Natural selection operates on existing genetic variation within a population. It favors individuals with traits that are advantageous for survival and reproduction in a given environment, gradually increasing the frequency of those advantageous alleles while potentially reducing the frequency of less favorable ones.

Mutation introduces new genetic variations by altering DNA sequences. It is the original source of genetic diversity in any population and can lead to new traits that may be subject to natural selection. Over time, certain mutations may become common while others may be lost.

Understanding the roles of these factors is crucial for studying evolutionary processes and population genetics, as they collectively contribute to how populations evolve over time. The other options represent important ecological concepts or processes but do not directly account for the mechanisms that actively change the genetic composition of populations in the way that migration, selection, and mutation do.