What is the process called where organisms that are better adapted to their environment survive and reproduce?

The process where organisms that are better adapted to their environment survive and reproduce is known as natural selection. This concept, central to evolutionary biology, was popularized by Charles Darwin. Natural selection occurs because individuals within a species exhibit variations in traits, such as size, color, or behaviors. Those traits that confer an advantage in a specific environment increase an organism's chances of survival and reproduction. Over time, these advantageous traits become more common within the population, leading to evolutionary changes.

Natural selection is distinct from genetic drift, which refers to random changes in allele frequencies in a population, particularly in small populations. It also differs from adaptive radiation, which describes a process where a single ancestor species diversifies into a wide variety of forms to adapt to different environments. Speciation is the process by which new species arise from existing ones. While all these concepts are related to evolution, natural selection specifically focuses on the survival and reproductive success of organisms based on their adaptation to the environment.