What is the process called when a new species is formed from an existing species?

Speciation is the process through which a new species arises from an existing species. This occurs when populations of the same species become isolated from one another, either geographically or reproductively, leading to the accumulation of genetic differences over time. As these differences grow, they can result in distinct traits, behaviors, or reproductive mechanisms that prevent the populations from interbreeding successfully, thus culminating in the formation of a new species.

Understanding this process is crucial in evolutionary biology, as it explains biodiversity and the mechanisms behind how organisms adapt to their environments over time. The concept of speciation encompasses various models, including allopatric speciation (which happens due to geographical isolation) and sympatric speciation (which occurs without geographical barriers).

In contrast, microevolution refers to small-scale evolutionary changes within a species or population, often involving changes in allele frequencies. Genetic drift is a mechanism of evolution that leads to changes in the genetic composition of a population due to random sampling effects, not necessarily tied to the formation of new species. Phenotypic change focuses on observable traits influenced by genetic and environmental factors rather than the broader framework of species formation. Thus, speciation specifically denotes the creation of new species, which distinguishes it from these other concepts.