Evolution is the change in heritable characteristics of biological populations over successive generations. It occurs through the mechanisms of natural selection, genetic mutation, and genetic drift. Natural selection refers to the process by which organisms best suited to their environment are more likely to survive and reproduce, passing on their advantageous traits to their offspring. This results in the accumulation of beneficial traits in a population over time. Genetic mutation creates variations in traits that may be beneficial or detrimental to an organism’s survival and reproduction, while genetic drift refers to the changes in a population’s gene frequency due to random chance events. These mechanisms work together to drive the process of evolution, leading to the diversity of life we observe today.