Test #2 Lecture Notes xx.pdf - ANTHP 105 Exam#2 Modern...

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ANTHP 105: Exam #2 Modern human evolution & adaptations 10/10-10/13 1.Human origins & worldwide expansion 2.Serial founder effect: effects of drift and mutation 3.Local adaptations: skin color, body proportions, altitude, malaria, lactase persistence Replacement Model: There was not a genetic contribution from Neanderthals or H. erectus. DNA Phylogeny of Modern Human Populations oOur genetic tree is rooted in Africa, 200kya o90% of alleles can be found within any single population because populations around the globe are very genetically similar oPopulation structure reflects migration out of Africa all one continuous gene pool, NOT separate “races”oOur species, homo sapiens, originated 200kya in Africa oWe then spread all over the world, replacing other hominins. oHowever, we did interbreed a little with Neanderthals & others. oToday, population DNA differences reflect migration: Geographic distance = genetic difference But differences are very small! oInterbreeding and gene flow are powerful forces in the human species. oThere are no “pure” populations. We’re all from one big, mixed gene pool.oMost population differences are due to drift and mutation. oSkull shape is one example of this. oA small amount of human global variation has been shaped by natural selection local adaptations to local conditions Local Adaptations oSkin color and ultraviolet radiation (UVR) UV-A is bad: destroys folate, which is needed for DNA synthesis UV-B is good: critical for vitamin D production UVR is necessary for the production of vitamin D but dangerous at high levels There is a strong correlation between the amount of annual UVR exposure at Earth Surface with the amount of melanin found within a specific area. oBody shape & size and climate
ANTHP 105: Exam #2 Allen and Bergmann “rules” for body shape and climate Cold climate heavier, shorter limbs Hot climate lighter, longer limbs Average body proportion shorter limbs in cold climates oMalaria resistance Malaria a parasite spread by mosquitos Many independently evolved adaptations for malaria resistance world wide Adapatation Where? Duffy Africa Elliptocytosis Melanesia Sickle cell Africa Africa S.E. Asia Africa, S.E Asia G-6-PD deficiency Africa, Mediterranean, India, S.E. Asia Culture can affect biology simple farming methods increase mosquito habitat oAltitude Independently evolved adaptations A day in the life of a traditional hunter-gatherer 10/13 1.Hunter-Gatherer societies as in Human Evolution & Health 2.The Hadza: a case study a.Their environment: the African Savannah b.Social Organization c.Foraging (getting food) strategies d.Diet: Hunting & Gathering Hunting and gathering means no farming or market economy oNo cities and towns oSmall scale populations get food from the wild oThe people of Tanzania speak both Hadza and Swahili Shy-Amo good morning Social Structure: Egalitarian oNo “chief”: no government, no hierarchy oEgalitarian no power structure, no police, no government, men and women treated as equal oWomen can leave camp together to collect plant foods

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