What is speciation?

What is speciation?

• A. The extinction of a species due to environmental changes.
• B. The gradual change of a single population over time without forming new species.
• C. The migration of individuals between populations, increasing gene flow.
• D. The formation of new and distinct species in the course of evolution, often via reproductive isolation.

Answer: (D)

Speciation is the formation of new and distinct species in the course of evolution, often via reproductive isolation. When populations become isolated from one another, gene flow between them decreases, allowing genetic differences to accumulate through mutation, natural selection, and genetic drift. Over time, these differences can create incompatibilities such that the two groups no longer interbreed successfully, even if they come back into contact, which marks them as separate species. There are different paths to speciation, like allopatric speciation where geographic barriers split populations, and sympatric speciation where reproductive barriers arise without a geographic split. Reproductive isolation can be prezygotic (preventing mating or fertilization) or postzygotic (hybrids are inviable or infertile). The other descriptions refer to extinction, gradual change within a single lineage without forming new species, or ongoing gene flow, none of which describe the origin of new species through isolation.

Speciation is the formation of new and distinct species in the course of evolution, often via reproductive isolation. When populations become isolated from one another, gene flow between them decreases, allowing genetic differences to accumulate through mutation, natural selection, and genetic drift. Over time, these differences can create incompatibilities such that the two groups no longer interbreed successfully, even if they come back into contact, which marks them as separate species.

There are different paths to speciation, like allopatric speciation where geographic barriers split populations, and sympatric speciation where reproductive barriers arise without a geographic split. Reproductive isolation can be prezygotic (preventing mating or fertilization) or postzygotic (hybrids are inviable or infertile). The other descriptions refer to extinction, gradual change within a single lineage without forming new species, or ongoing gene flow, none of which describe the origin of new species through isolation.