Question

in light of the out - of - africa hypothesis, which of the following is a parsimonious reason why species like homo neanderthalensis, homo floresinensis, and homo erectus do not exist today?
extensive gene flow between human populations led to a blending of traits that resulted in the evolution of homo sapiens.
climate change in africa caused the extinction of all hominin populations except for the ones that gave rise to modern homo sapiens.
modern homo sapiens out - competed and replaced other hominin species as they migrated around the world.
as modern homo sapiens developed new and more accurate hunting skills they were able to hunt other hominin species to extinction.

Explanation:

The "out - of - Africa" hypothesis posits that modern Homo sapiens originated in Africa and then migrated to other parts of the world. When considering parsimony (the principle that the simplest explanation is often the best), the idea that modern Homo sapiens out - competed and replaced other hominin species as they migrated is a straightforward explanation. Gene flow (first option) is more complex in terms of how it would lead to the extinction of multiple distinct species. Climate change in Africa (second option) is too limited in scope as these species were not all in Africa when they went extinct. Hunting other hominins to extinction (fourth option) is a more specific and perhaps less likely scenario compared to out - competing in terms of resources, territory, etc.

Answer:

Modern Homo sapiens out - competed and replaced other hominin species as they migrated around the world.