What is the name of the process where organisms better adapted produce more offspring?

The process in which organisms with traits better suited to their environment produce more surviving offspring is called natural selection. Over generations, heritable traits associated with greater reproductive success become more common in a population.

Natural selection requires variation among individuals, inheritance of at least some of that variation, and differences in survival or reproduction. The environment does not consciously choose organisms, and individuals do not evolve because they “need” a trait. Instead, existing heritable differences affect which organisms leave more descendants.

Charles Darwin published his theory of evolution by natural selection in On the Origin of Species in 1859. He was influenced by observations from the second voyage of HMS Beagle, selective breeding by humans, and Thomas Malthus's 1798 argument that populations can grow faster than their food supplies. Alfred Russel Wallace independently developed a similar theory.

Natural selection differs from genetic drift, which changes trait frequencies through chance, especially in small populations. It also differs from artificial selection, in which humans choose which organisms reproduce. Sexual selection is a form of natural selection involving differences in mating success, such as competition or mate choice.