Genetic variation refers to the differences in DNA sequences between individuals within a species. These variations arise from mutations, gene flow, genetic recombination and other mechanisms that change the genetic makeup of an organism. Genetic variation is essential for evolution as it provides the raw material upon which natural selection can act. It also allows populations to adapt more effectively to changing environments or selective pressures. In a species with high levels of genetic variation, individuals are better equipped to survive and reproduce in diverse conditions, thus increasing their chances of long-term survival as a species.