[2] When speciation does occur as different lineages branch off and cease to interbreed, a core group may continue to be defined as the original species.
[3] One hypothesis is that during the speciation event in anagenetic evolution, the original populations will increase quickly, and then rack up genetic variation over long periods of time by mutation and recombination in a stable environment.
Researchers were curious to know if present day humans originated from Africa, or if they somehow, through anagenesis, were able to evolve from a single archaic species that lived in Afro-Eurasia.
[12] Milford H. Wolpoff is a paleoanthropologist whose work, studying human fossil records, explored anagenesis as a hypothesis for hominin evolution.
Wolpoff contended that the ecological niche of past, extinct hominidae is distinct within the line of origin.
[4] Examining early Pliocene and late Miocenes findings helps to determine the corresponding importance of Anagenesis vs. Cladogenesis during the period of morphological differences.
[14][15][16][17][18] However, looking at data collected by William H. Kimbel and other researchers, they viewed the history of early hominin fossils and concluded that actual macroevolution change via anagenesis was scarce.
[20] Controversy arises among taxonomists as to when the differences are significant enough to warrant a new species classification: Anagenesis may also be referred to as gradual evolution.
The distinction of speciation and lineage evolution as anagenesis or cladogenesis can be controversial, and some academics question the necessity of the terms altogether.