Dispersal Flashcards
Out of Africa Hypothesis
suggests that all genes in modern-day humans came out of Africa, as recently as 65,000ya when modern H.sapiens migrated around earth and replaced all other human populations
Who left Africa first? OoA
Homo Erectus left first and colonised areas around 1mya
who migrated after Homo erectus? OoA
H.sapiens migrated and outcompeted the old/archaic populations
What happened when H.sapiens migrated? OoA
archaic population became extinct as H.sapiens were more developed and outcompeted
how were species established? OoA
geographical barriers separated populations, so no gene flow occurs and speciation occurs
Evidence for Out Of Africa
H.sapiens fossils found in Africa at the same time as H.erectus and H.neanderthalensis
reasons for migration
more recouses, increased curiosity, improved locomotion, better equipped to exploit new land
Extinction
end of an organism or group
dispersal
process of distributing or spreading of people over a wide area
gene flow
movement of alleles in to or out of a population due to the migration of individuals to or from the population
Multi-regional hypothesis
suggests that modern-day humans resulted from the mixing of alleles between European, Asia, and African populations of H.sapiens and each population evolved parallel when they diverged 1.8mya
When did H.erectus leave africa? MRH
1.5mya and dispersed regional populations and evolving to modern day humans
Where did H.erectus colonise? MRH
Europe, Asia, Australasia, and Africa around the same time
Is there gene flow in MRH?
gene flow did exist between adjacent populations and so mixing of alleles occurs, preventing speciation
Hypothesis
proposed model to explain something based on evidence
Admixture
mixing/moving of gene from one population to another
reproductive isolation
inability of a species to breed successfully with related species due to geographical, behavioural, physiological or genetic barriers
Simultaneously
events occurring concurrently, side by side, at the same time
Mitochondrial DNA
DNA found in the mitochondria, inherited from mother, unique and separate to Nucleus DNA. Helps to track genes through time
Eve mtDNA
haplogroup/haplotype a group of alleles in an organism that are inherited from only one parent, inherited from mother. Almost identical through generations
Maternal Line
Y Chromosome
only inherited from male. Not subject to independent assortment or crossing over, can help to track families back
Paternal Line
Molecular clock
technique that uses the mutation rate to understand how related DNA is, and therefore how related the life forms are
mtDNA and Y chromosome DNA
How do mutations show pathway across planet
Eve mtDNA accumulates mutations that show a pathway across the planet
Mutations found across multiple populations
