Mutation, migration, genetic drift, and natural selection are all mechanisms that can affect evolutionary processes.
Mutation is the process by which genetic material changes, resulting in genetic variation. For example, a mutation in the genetic code of a fruit fly might result in a new wing shape.
Migration refers to the movement of individuals or groups of individuals from one population to another. This can result in genetic variation as migrants bring new genetic combinations to the population. For example, a group of birds might migrate to a new area and mate with the resident population, introducing new genetic variations.
Genetic drift is the random fluctuation of allele frequencies in a population due to chance events. This can result in certain alleles becoming more or less common in a population over time. For example, imagine a population of butterflies with 2 different wing colors black and white. If a natural disaster kills most of the white-winged butterflies, the black-winged allele may become more common in the population due to genetic drift.
Natural selection is the process by which certain traits become more or less common in a population over time because they confer a survival or reproduction advantage. For example, imagine a population of birds living in a forest with a lot of predators. Birds that are better at camouflage will be less likely to be spotted and killed by predators. These birds will live longer, reproduce more and pass the camouflage gene to their offspring. Over time, the population of birds will become more and more camouflage-colored.
It is important to note that all these mechanisms can act simultaneously and interact with each other, affecting the evolutionary process.