Map of early diversification of modern humans according to mitochondrial population genetics see:
Lucy is estimated to have lived 3. Cleveland Natural History Museum, photo by Andrew.
Around 30, years ago humans were anatomically and behaviorally similar throughout the world. One of the most hotly debated issues in paleoanthropology the study of human origins focuses on the origins of modern humans, Homo sapiens.
However, by 30, years ago this taxonomic diversity vanished and humans everywhere had evolved into the anatomically and behaviorally modern form. The nature of this transformation is the focus of great deliberation between two schools of thought: Understanding the issue Multiregional theory: The Multiregional Continuity Model15 contends that after Homo erectus left Africa and dispersed into other portions of the Old World, regional populations slowly evolved into modern humans.
This model contains the following components: Critical to this model are the following tenets: Out of Africa theory: The replacement hypothesis suggests that the genes in fully modern humans all came out of Africa.
As these peoples migrated they replaced all other human populations with little or no interbreeding. To understand this controversy, the anatomical, archaeological, and genetic evidence needs to be evaluated.
Anatomical evidence Sometime prior to 1 million years ago early hominids, sometimes referred to as Homo ergaster, exited Africa and dispersed into other parts of the Old World.
Living in disparate geographical areas their morphology became diversified through the processes of genetic drift and natural selection. In Europe and western Asia they evolved into the Neanderthals.
Neanderthals lived in quasi isolation in Europe during a long, relatively cool period that even included glaciations. Neanderthals are distinguished by a unique set of anatomical features, including: This is a classic example of geographic isolation leading to a speciation event. In contrast, at roughly the same time, in Africa, a body plan essentially like our own had appeared.
While these early Homo sapiens were anatomically modern they were not behaviorally modern. It is significant that modern anatomy evolved prior to modern behavior.
These early sapiens were characterized by: Archaeological evidence Very interestingly, while Neanderthals and early Homo sapiens were distinguished from one another by a suite of obvious anatomical features, archaeologically they were very similar.
This was an abrupt and dramatic change in subsistence patterns, tools and symbolic expression. The stunning change in cultural adaptation was not merely a quantitative one, but one that represented a significant departure from all earlier human behavior, reflecting a major qualitative transformation.
The appearance of fully modern behavior apparently occurred in Africa earlier than anywhere else in the Old World, but spread very quickly, due to population movements into other geographical regions. The Upper Paleolithic lifestyle, as it was called, was based essentially on hunting and gathering.
So successful was this cultural adaptation that until roughly 11, years ago, hominids worldwide were subsisting essentially as hunter-gatherers. It was characterized by significant innovation: Precisely how this transformation occurred is not well understood, but it apparently was restricted to Homo sapiens and did not occur in Neanderthals.
Some archaeologists invoke a behavioral explanation for the change. For example, Soffer11 suggests that changes in social relations, such as development of the nuclear family, played a key role in bringing about the transformation.The "Out of Africa" theory is used in paleoanthropology to explain the geographic origin of modern day humans, and it asserts that modern humans evolved recently in Africa and migrated out into Eurasia, replacing all the regions that were once populated by lineages connected to Homo erectus.
The 'Out of Africa' Hypothesis, Human Genetic Diversity, and Comparative Economic Development. Quamrul Ashraf. in the course of the exodus of Homo sapiens out of Africa, Consistent with the predictions of the theory, the empirical analysis finds that the level of genetic diversity within a society has a hump-shaped effect on development. New research confirms the "Out Of Africa" hypothesis that all modern humans stem from a single group of Homo sapiens who emigrated from Africa 2, generations ago and spread throughout Eurasia. The “Out of Africa” hypothesis is an evolutionary theory of modern human origin that posits that modern humans arose in the late Pleistocene, about ,–, years ago, in Africa.
Out of Africa 1 contends that earlier Homo species did in fact migrate from Africa before the evolution of H. sapiens. Out of Africa 2 (also called the population replacement hypothesis) picks up where Out of Africa 1 leaves off. The “Out of Africa” hypothesis is an evolutionary theory of modern human origin that posits that modern humans arose in the late Pleistocene, about ,–, years ago, in Africa.
New research confirms the "Out Of Africa" hypothesis that all modern humans stem from a single group of Homo sapiens who emigrated from Africa 2, generations ago and spread throughout Eurasia. The Out of Africa (OoA) or African Replacement Hypothesis is a well-supported theory that argues that every living human being is descended from a small group of Homo sapiens (abbreviated Hss) individuals in Africa, who then dispersed into the wider world meeting and displacing earlier forms such as Neanderthals and Denisovans.
Out of Africa theory: homo sapiens arose in Africa and migrated to other parts of the world to replace other hominid species, including homo erectus. after Homo erectus migrated out of Africa the different populations became reproductively isolated, evolving independently, and in some cases like the Neanderthals, into separate species.