Lectures 19-20 Flashcards Preview

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Flashcards in Lectures 19-20 Deck (12)
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What is the the family for feet apes



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

1. 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

3. 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