Evolution: Dispersal Patterns Flashcards
What does the Multiregional Hypothesis suggest about the migration of Homo Erectus?
Homo Erectus migrated out of Africa about 1.8 million years ago, spreading to Europe and Asia while simultaneously evolving into Homo Sapiens.
How did continuous gene flow affect human populations according to the Multiregional Hypothesis?
It ensured adaptations were spread to all populations, leading to similar features among all humans.
What evidence supports the idea of interbreeding between Homo Erectus, Neanderthalensis, and modern Homo Sapiens?
Fossils and DNA evidence show regional intermediates between these species, indicating that interbreeding occurred.
What percentage of Neanderthal DNA is found in modern Europeans?
Up to 4%, with at least 2.5% being common. (Supports Out of Africa theory - interbreeding occured, species interacted.)
Why is the Multiregional Hypothesis considered unpopular?
It requires high levels of gene flow, which is unlikely, and genetic evidence shows less variation than expected.
What does mtDNA evidence suggest about the variation within a species?
Significant variation within mtDNA can occur within a species, as seen in a subspecies of chimpanzees.
What do regional differences in some populations suggest according to the Multiregional Hypothesis?
They suggest regional adaptation, similar to Homo Neanderthalensis.
What is a major issue with using fossil evidence to support the Multiregional Hypothesis?
Fossils cannot confirm a species’ ability to successfully interbreed.
What does the presence of intermediate fossils between Homo Erectus and Homo Sapiens in Israel suggest?
It suggests that some gene flow occurred and that these fossils are close to Africa.
Why is the belief that 170,000 years is too short to develop racial differences significant?
It supports the idea that interbreeding and regional adaptation took longer, aligning with the Multiregional Hypothesis.
What does the presence of Neanderthal DNA in modern Europeans indicate?
It indicates that interbreeding took place in the past.
Why is the Multiregional Hypothesis highly questionable based on recent genetic research?
Because mtDNA and Y chromosome DNA reveal less variation than expected, suggesting a later migration out of Africa.
Mutliregional Model:
Modern Africans, Asians, and Europeans evolved in their separate regions.
There was sufficient gene flow to prevent them diverging into separate species.
They have a common ancestor, H. Erectus who left Africa 1.8MYA.
Evidence: Multiregional Theory
- Modern H. Sapiens should have similar amount of genetic diversity as African
populations because they have been evolving for just as long.
-Variation within regional populations should be larger as they have had a long time
to accumulate regional differences.
Out of Africa theory:
Modern humans
originated in Africa and migrated out to Europe and western Asia
where they encountered, interbred with and ultimately outcompeted archaic
hominins who had left Africa much earlier and had evolved into regional variants
(Neanderthals & Denisovans)
2 great migrations, one involving H. Erectus who evolved into Neanderthals and a
second one involving Homo Sapiens leaving africa in waves about 100 - 50 000 yrs ago
