Final answer:
The four forces of evolution are mutation, which introduces new genetic variations; gene flow, which allows alleles to move between populations; genetic drift, causing random allele frequency changes; and natural selection, which favors certain alleles based on environmental pressures.
Step-by-step explanation:
The four main evolutionary processes that contribute to the genetic variation and evolutionary changes in populations are mutation, gene flow, genetic drift, and natural selection.
- Mutation is a process by which new genetic information is introduced into a gene pool, creating new genetic variability.
- Gene flow, also known as migration, is the transfer of alleles between populations, which can alter allele frequencies.
- Genetic drift describes random fluctuations in the frequencies of alleles within a population, which can have a larger effect in small populations.
- Natural selection is the differential survival and reproduction of individuals due to differences in phenotype, leading to changes in allele frequencies over time.
These processes are fundamental in understanding how populations evolve and adapt to their environments. Mutations provide the raw material for evolution by introducing new alleles, while gene flow can spread these alleles between populations. Genetic drift can cause significant changes in small populations by chance alone. Finally, natural selection acts on the genetic diversity within a population, favoring the alleles that contribute to reproductive success and survival.