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19 Cards in this Set
- Front
- Back
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4 general statements, based on genetic evidence, about the origin and spread of Homo sapiens
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1) modern humans evolved in African 100-200 kya
2) All non-African populations are all descended from a small population that left East African approx. 60 kya 3) This population spread rapidly along the southern coast of Asia, and then moved north and west into Eurasia 4) There was a small amount of interbreeding between expanding humans and other hominins living in Eurasia (Neanderthals 2.5%, Denisovans to Papa New Guineans 4.8%) |
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Y-chromosome
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nuclear DNA
transmitted paternally 95% is non-recombinant (very little change makes it trackable) very few genes on it → doesn’t code for much, not very affected by natural selection |
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mtDNA
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mitochondrial DNA
transmitted maternally non-recombinant found in the mitochondria = powerhouse of cells codes for 12 proteins used by the mitochondria |
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Which has more genetic diversity, humans or chimps?
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Chimps
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2 individuals from Africa differ in about __% of their nucleotide bases
2 individuals from Africa and Europe differ in __% of their nucleotide bases |
Africa = 2.5%
Europe and Africa = <0.3% |
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Modern human genome evolved mainly under the influence of _____ and ______
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drift and mutation
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We descended from a group of how many females
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5000
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Genetic consequences of having a small population migrating rapidly across the landscape
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small population expanded very rapidly through Asia
rapid expansion of a small group → new variations (mutations) are added very slowly simultaneously, drift reduces/limits variability within small populations |
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Mutations as a function of time...
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• negative correlation between measures of genetic variation and geographical distances
• the longer the branch of a gene tree, the older the mtDNA sequence • non-African branches are shorter than many African branches |
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Last common ancestor existed...
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approx. 465-569 kya
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Genetic evidence pertaining to the interbreeding between Homo sapiens and other hominins
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• mtDNA sequence is genetically distinct from the Neanderthals and modern humans
• Nuclear DNA suggests that this group shares a common origin with Neanderthals • interbreeding between Denisovans and Papas must occurred after split of modern humans, because other human populations do not have Denisovan DNA • Neanderthals 2.5%, Denisovans to Papa New Guineans 4.8% |
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Timing of the last common ancestors between humans, Neanderthals and the Denisovans
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Split of heidelbergensis to humans and Neanderthals → 800 kya
Split of LCA to Denisovans and Neanderthals → 640 kya Split within Neanderthals → 140 kya |
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Biocultural evolution
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• evolution through combination of genetic and cultural forces
• biology → interplay between genotype, phenotype, and environment • culture → culture is the human ecological niche → form of extrasomatic adaptation |
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extrasomatic
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means of adaptation work against evolution of significant changes in body structure in modern humans
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modern human morphology evolved...but...until...
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between 250 - 60 kya
but they still behaved like contemporaneous Neanderthals until... approx. 60 kya rapid transition to more modern behavior in Africa |
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Timing of dramatic shift of modern human behavior in European archaeological record
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approx. 50 kya
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Time frame of cultural revolution (3)
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• technological advance since before 10 kya with development of agriculture
• piecemeal, gradual accumulation of behavioral changes over 200,000 years |
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Aspects of cultural revolution (6)
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• shift in cognitive ability that did not lead to detectable changes in skeleton -> extrasomatic
• stone and non-stone technology • evidence of blade production → mode 4 • composite tools (hafting) • long distance transportation of raw material • ornamentation → symbolic expression → perforated shells |
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Most Middle Paleolithic sites are located in...
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France
suggests a bias |
