Evolution occurs through mechanisms like natural selection from "summary" of The Structure of Evolutionary Theory by Stephen Jay Gould
The central principle of evolution is natural selection, a process in which certain traits are favored over others due to their ability to confer a reproductive advantage upon their possessors. This mechanism drives the gradual change of species over time, as those individuals with advantageous traits are more likely to survive and pass on their genes to future generations. Natural selection operates on variation within a population, selecting for traits that increase an organism's chances of survival and reproduction in a given environment. In addition to natural selection, evolution can also occur through other mechanisms such as genetic drift, gene flow, and mutation. Genetic drift refers to random changes in gene frequencies within a population, which can lead to the fixation of certain alleles and the loss of others. Gene flow occurs when individuals from different populations interbreed, leading to the exchange of genetic material and the introduction of new alleles into a population. Mutation, on the other hand, is the ultimate source of genetic variation, providing the raw material upon which natural selection can act.- It is important to recognize that it is not the only driver of evolutionary change. The interplay of various mechanisms, including genetic drift, gene flow, and mutation, shapes the genetic composition of populations and ultimately determines their evolutionary trajectory. By understanding the complex interplay of these mechanisms, we can gain insight into the process of evolution and the diversity of life on Earth.
