What evolutionary mechanism involves the survival of organisms better adapted to their environment?

The mechanism that involves the survival of organisms better adapted to their environment is natural selection. This fundamental concept of evolution, first articulated by Charles Darwin, explains how certain traits become more common in a population over time. Organisms that possess advantageous traits that enhance their fitness—meaning their ability to survive and reproduce in a specific environment—are more likely to pass those traits to subsequent generations.

For instance, if a particular environment favors organisms with a specific coloration or physical characteristic that allows them to evade predators or better capture food resources, those individuals will have greater reproductive success than their peers. Over many generations, these advantageous traits increase in frequency within the population, leading to evolutionary change.

In contrast, other mechanisms mentioned do not directly relate to the concept of adaptation in the context of survival and reproduction. Gene flow refers to the transfer of genetic material between populations, which can introduce new alleles but does not inherently favor the survival of adapted organisms. Mutation is the source of genetic variation, which can lead to adaptations but does not involve selection per se. Speciation is the process by which new species arise, often as a result of accumulated changes, but it does not specifically address the mechanism of adaptation and survival in a given environment.