What scientific theory explains the mechanism of evolution?

Natural selection is the scientific theory that explains the mechanism of evolution. This concept, formulated by Charles Darwin, describes how individuals within a population that possess advantageous traits are more likely to survive and reproduce, thereby passing those traits on to future generations. Over time, this process can result in changes to the population's genetic makeup, leading to the evolution of species.

Natural selection operates on the premise that there is variation within populations, and that certain traits confer a survival advantage in a given environment. This selective pressure leads to the gradual adaptation of organisms to their surroundings. Thus, the theory of natural selection is foundational to our understanding of how species evolve over time and how complex biological diversity arises.

While genetic drift, the theory of inheritance, and mutation theory contribute to the understanding of evolutionary processes, they are not primary mechanisms of evolution on their own. Genetic drift refers to random changes in allele frequencies in a population, the theory of inheritance (often linked to Mendelian genetics) explains how traits are passed from parents to offspring, and mutation theory addresses the role of genetic mutations in introducing new variations. However, natural selection is the overarching theory that integrates these concepts into a cohesive explanation of evolutionary change.