Final answer:
Genetic evolution is driven by mechanisms including natural selection, genetic drift, and gene flow. Genetic drift involves random changes in allele frequencies, while gene flow is the introduction of new genetic material via migration. Both processes, along with mutation, contribute to evolution and speciation.
Step-by-step explanation:
Aside from natural selection, two other mechanisms of genetic evolution that complement it are genetic drift and gene flow. Genetic drift occurs due to random fluctuations in allele frequencies within a population, which can lead to significant changes over time, especially in small populations. Gene flow, on the other hand, involves the transfer of genes between populations through migration of individuals or the transfer of gametes, leading to a mixture of genetic material and potentially introducing new genetic variants into a population.
While natural selection is a non-random process that favors the survival of individuals with advantageous traits, genetic drift can cause allele frequencies to change at random, which may not necessarily provide any survival or reproductive advantage. Together, these mechanisms, along with mutation, contribute to the overall process of evolution by influencing the genetic makeup of populations and eventually leading to the emergence of new species through processes such as speciation.