Lectures 19-20 Flashcards
(12 cards)
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
