Alena Sazonova
Teresa Potter
Anthropology 1020
December 1, 2018
Modern Human Origins
The discussion of modern human origins has been ongoing for at least the last century.
The two main theories that are debated by scientist are Regional Continuity and Replacement.
Regional Continuity is built on the assumption that various forms of early hominids such as
homo neanderthalensis and homo sapiens interbred and over time evolved into modern
humans we see today. The Replacement theory hypothesizes that modern human origins can
be traced back to a single common African ancestor. Some anthropologist refer to this single
ancestor as “Eve”. (3)
According to the Regional Continuity theory, there are multiple points of origin for
modern humans. The evolution of modern humans is thought to have occurred during the
Middle Pleistocene. During this period there was more diversity within these early hominid
populations than what exists today. Europe was mostly populated by homo neanderthalensis,
Africa and the Middle East by homo sapiens, and other related groups in Asia. The theory is
built on the concept that there was a fair amount of interbreeding between these early groups
of hominids, which eventually led to the speciation of modern humans. (1,4)
Nevertheless the Regional Continuity theory does not account for the fact that as of
around 30,000 years ago, there was a sudden drop in the variation between hominids.
Neanderthals and other variations of hominids seemingly drop off the fossil record, replaced by
modern humans. Critics of the theory claim that there would not have been enough
interbreeding to prevent speciation between the geographically isolated groups (1,4)
The theory also does not account for the fact that we currently have one very closely
related species roaming the planet modern humans. It has been stated that it would be
an “evolutionary miracle” for modern humans to have branched off as early as the Regional
Continuity theory suggests and for the world’s populations to have remained so similar. Though
there are certainly variations within our species it would be expected that given the amount of
geographical isolation, modern human populations throughout the world would not have
remained so similar since the Middle Pleistocene. (3)
The Replacement theory, however is built on filling in the holes left by the Regional
Continuity theory. According to this second theory, modern humans arose out of a common
African ancestor fairly recently between 50,000 to 500,00 years ago (usually estimated to be
around 200,000 years ago). This common African ancestor is hypothesized to be of the earliest
forms of modern humans and had already undergone speciation which meant there could have
been no interbreeding between modern humans and other hominids during the Pleistocene
Era. (3)
Around 30,000 years ago, diversity in hominid populations diminished. The Replacement
theory explained this sudden lack in diversity with the hypothesis that modern hum...
