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Where do we see the earliest modern h. sapiens?
- Africa: Middle Awash in Ethiopia dated to 160kya.
- Middle East: ~92kya.
What is modern human morphology?
- Presence of chin.
- High and rounded cranium.
- Slight decrease in cranial capacity - ~ 1350.
- general decrease in size and ruggedness.
- Smaller teeth.
What is the multiregional model?
- A single evolving population, with distinct regional subdivisions.
- Human first arose near the beginning of the Pleistocene 2mya, and subsequent human evolution has been as a single, continuous human species.
What is the out of africa hypothesis?
- AMHs evolved solely in Africa between 200-150kya. They dispersed between 125-60kya and replaced existing pops, such as Neanderthals and h. erectus.
- Single exodus or multiple exoduses?
- Different theories just change with who is the more recent ancestor, heidelbergensis or antecessor or helmei.
mtDNA evidence for theories:
Supports recent African origin. Most human genetic diversity is in Africa.
Problems with mtDNA:
- Sampling: Analysis is limited by sample. Includes genetic drift problems.
- Parsimony Analysis: Many possible trees have to be considered. Too many for even contemporary computers. Therefore, choices are made.
- Regions of MtDNA: Analysis may depend on regions used.
Y- chromosome evidence:
Greatest diversity in Africa.
- Definition: Coalescence times cluster around a time of population division, thereby indicating a new species.
- Support OoA/single origin theories.
Dispersal and tools:
- Where more modern tool modes and such are found, more modern humans lived.
- Mode 4 and 5 appears with AMH.
- Gracile forms.
- Reduced brow ridges.
- Reduced cranial capacity.
- Prominent chin.
- Vertical forehead.
- Modern anatomy first appears ~ 195kya.
Late Pleistocene Europe, Africa, Asia:
- Europe: Last of the Neanderthals.
- Africa: Transitional forms heidelbergensis.
- Asia: Not so much continuity. Dating problems.
Are there any transitional forms? What happened to the otehr species of Homo?
H. heidelbergensis in Africa, yes. The other species of Homo died out/were replaced.
What theory best explains the appearance of Homo sapiens?
I believe that the recent African origin of modern humans is the most likely theory. The genetic diversity found in Africa that is not found elsewhere in the globe, as well as fossil evidence found in Africa, supports my theory.