Speciation

Speciation is the process by which one species evolves into one or more distinct new species, and is regarded as a fundamental process within evolution as a whole. A.E. Emerson defined a species as a 'genetically distinctive, reproductively isolated natural population'. Two broad patterns of speciation are recognised by how many resulting lineages there are: if a single lineage simply evolves into a new species over time without branching, this is called anagenesis or phyletic speciation; if instead one ancestral species diverges into two or more descendant species, this is called cladogenesis or divergent evolution. The two subsections tha …