Lectures 19-20 Flashcards
What is the the family for feet apes
Hominidae
When did the homo genus range expand out of Africa
1.8 MYA
Who were the first humans
homo habilis
4 theories why we became bipedal
– Frees the hands for fine manipulations
– Greater stamina for long distance travel
– More effective hunting
– Improved ability to carry food
What is a karyotype
is the number and appearance of chromosomes in the nucleus of a eukaryotic cell
What is the difference between karotypes in gorillas, chimps and humans
Gorillas, Chimps, n = 24 chromosome pairs, after split from chimps, 2 chromosomes fused so humans n = 23
What is the relationship between bipedalism and living in the savanna
Many theories link bipedalism to living in a savanna – where A. afarensis lived but prior to this A. anamensis (4mya) – thought to be bipedal - existed in dry woodland
What are the 3 origin theories of modern humans
- Out of Africa - Emerged recently in Africa –
spread and replaced archaics
2) Multi-regional evolution
Hominin populations - evolved in situ into modern
homo populations – with gene flow between
Implies ancestral forms = not biological spp
- Hybridisation & assimilation - a mixture of the two other models, non-African archaics contributed to the gene pool of modern humans that expanded
into each region?
How much of modern Eurasian human genome is from Neanderthal
1-4% Green et al 2010
What is the currently accepted theory for the origin of humans
From east or south Africa – 200,000 years ago
Recent expansion - with small sequential colonisation events
Replaced archaic forms of hominins – with some introgression
What is the worldwide Fst
Worldwide Fst = 0.15; so 80% of variation found
within populations and only 20% among pops.
Means low level of gene flow since human expansion
Example of natural selection driving variation in modern humans
Lactose tolerance
Skin colour
HIV and the CCR∆5 gene
