Human evolution Flashcards
where did all modern humans originate
Africa
where was the first evidenceof human migration
Greece and China
but these populations woulda died out and their lineages didnt carry on
when was the first dispersal of the humnas that gave rise to modern populations
what couldve caused this dispersal?
~70,000 years ago
left africa, through middle east into other continents
perhaps climate change, so left to find better food and shelter
when is our evidence for first human traces in north america and why is this now being questioned?
estimated ~ 12,00 yrs ago humans first travelled to NA
but, recently discovered footprints in New MExico from 20,000 yrs ago
so suggests maybe humans were there earlier
heterozygosity def
genetic variation
describe how heterzygosity changes with distance from East Africa
largest variation in Africa
as you get further away, variation decreases
cuz as people leave, only small part of the genetic pool leaves and reproduces
so you slowly lose heterozygosity as people move
see graph in onenote
Explain why pop size could’ve lead to human extinction ~50,000 yrs ago?
bottleneck of ~12,000 people
could’ve been caused by climate change
so human genetic variablity is very little
so wouldn’t have taken much to wipe them out
Neanderthals
400,000-30,000 yrs ago (about 5000 yrs overlap w/ humans)
NOT ancestors, cousins = they left africa before modern humans
lived in family groups, had relationships
evidence for neaderthals having human like things and idk stuff
worn down teeth = used as a third hand to prepare animal hides and clothes and stuff
dived for shells and made string
made jewellery - shell and tooth necklaces with holes in it that were drilled in
made cave art - 65,000 yrs ago so humans were in middle east at this time
buried their dead with flowers by their bodies
why did neanderthals disappear
we dont know lol
but their populations were very small so easily wiped out
what was found when neanderthals genome was sequenced?
humans had interbred with neanderthals
so we’re not a seperate species as humans bred to make fertile offspring
only ~96 amino acid differences between humans and neanderthals
differences between us proably arised from regulatory gene differences
how were the Denisovans discovered?
tooth found in Denisova cave, and it deffo didnt belong to humans or neanderthals
and also tiny finger bone
was dated to ~40,000 yrs ago
which population have Denisovan genes
modern populations in asia
The EPAS1 allele in tibetans acc came from the denisovans
what’s the evidence that denisovans used boats
Wallace’s line
land animals are vry different on either side, cuz couldnt travel across
so only way denisovans could would’ve been using boats
evidence that neanderthals and tibetans mated
analysis of bones found in cave showed both genomes