1. What is Generally Agreed Upon?
The earliest hominids are all from Africa
The first to move out of Africa was H. erectus (ca. 1.7 mya)
H. erectus found its was to Asia and Europe relatively quickly

2. Modern Human Origins: Eve or Everywhere?
From which ancient population is modern humanity (H. sapiens) descended?
Two main theories today address this:
Multiregional Evolution, or Regional Continuity Model
Out of Africa, Mitochondrial Evem Recent African Origin, or Complete Replacement Model

3. The Basics of Each Model
Regional Continuity
Associated today with Milford Wolpoff
Been around since 1930’s, originating with Franz Weidenrich
Based on morphology of ancient modern Old World people
Complete Replacement
Associated with Allan Wilson, Rebecca Cann, and Mark Stoneking
Been around since 1987
Based on tracking mutations and modern genetic diversity in mtDNA (mitochondrial DNA) of 147 individuals from Africa, Asia, Europe, Australia, and New Guinea

4. The Particulars of Each Model
Regional Continuity
Continuance of physical traits from regional populations of H. erectus to Homo sapiens. Examples:
Australian aboriginals and Indonesian H. erectus have similar row and other traits
Modern east Asians and Asian H. erectus commonly share shoveled incisors, absence of third molars, and flat faces
Archaeology suggests a timeframe of mya to begin the process
Complete Replacement
Great diversity in mtDNA exists in modern Africans compared to other populations suggesting this is the root of the human tree
Molecular clock suggests a timeframe of perhaps 200,000 years back to a few common ancestors of all modern humans

5. The Implications of Each Model
Regional Continuity
Modern traits (e.g. huge forehead. Rounded skull, chin) arise at the same time everywhere
Gene flow between populations keep them from diverging too much
Predicts modern traits should occur in a mosaic
Transitional forms should be seen in each region
Complete Replacement
Modern traits appeared once (in Africa) and recently
Carriers of modern traits moved out and replaced archaic humans
Predicts all modern traits will be seen in Africa first
No transitional forms should be seen

6. The Bottom Line of Each Model
Regional Continuity
Archaeologically inconsistent
Ignores genetic evidence
Explains morphological continuity parsimoniously
Has been used to support dangerous ideas about race
Requires lots of gene flow
Implies need for total taxonomic simplification
Complete Replacement
Achaeologically consisten
Recognizes genetic evidence
Lacks a parsimonious explanation of trait continuity
Consistent with a polytypic, single species concept
Little gene flow required
No taxonomic change required