1. Natural Selection: This is the driving force of evolution. Individuals with traits better suited to their environment are more likely to survive, reproduce, and pass on those advantageous genes to their offspring. This leads to an increase in the frequency of beneficial genes in the population over time.
2. Genetic Drift: This is a random process that primarily affects smaller populations. It occurs due to chance events like natural disasters or random fluctuations in who reproduces, causing certain alleles (gene variations) to become more or less common in the population, even if they are not beneficial or harmful.
3. Gene Flow: This is the movement of genes between populations. It can occur through migration, where individuals from one population move to another, introducing new alleles or changing the frequency of existing ones. Gene flow can help maintain genetic diversity within a population or introduce new variations.
4. Mutation: While mutations occur randomly, they are the ultimate source of new genetic variation. They can introduce new alleles into a population, leading to changes in gene frequencies. While individual mutations might have a small impact, over time, the accumulation of mutations can contribute to significant evolutionary changes.
