What is the primary unit of evolution?

• A. Species
• B. Individuals
• C. Populations
• D. Genomes

Answer: (C)

The primary unit of evolution is populations. Evolution occurs as a change in the heritable traits of a population over successive generations. This process is driven by mechanisms such as natural selection, genetic drift, mutations, and gene flow, which act on the genetic variation within populations.

Populations consist of groups of individuals of the same species that live in a specific area and can interbreed, allowing for genetic exchange. It is these populations that adapt to their environments through evolutionary pressures, leading to speciation over time.

While individuals can display variations in traits, evolution is a process that is reflected at the population level, not at the individual level. Genomes provide the genetic material, and species are broader classifications of organisms that can include multiple populations, but it is the population that is key in understanding the dynamics of evolutionary change.