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What are the two major models of human origin and their supporters.txt

The flashcards below were created by user Anonymous on FreezingBlue Flashcards. Home Mobile Quiz What are the two major models of human origin and their supporters? Replacement (out of Africa) supported by Chris Stringer Regional continuity (multiregionalism) supported by Milford Wolpoff Replacement theory? Out of Africa AMH evolved in Africa (200-150kya), eventually dispersed out, and replaced archaic Eurasian populations as they met No (or minimal) admixture Complete replacement Regional continuity? Multiregionalism Older origin of Homo sapiens AMH evolved in concert across Eurasia and Africa Long-range gene-flow between archaic populations No replacement Not fully AMH, but almost? Florisbad, South Africa Ngaloba Beds, Tanzania (120 kya) KNM-ER 3884, Kenya (270 kya) Omo 2 (Kibish), Ethiopia (195 kya) Jebel Irhoud, Morocco (130 kya) Fully, anatomically modern human 195 kya to present? Klasies River Mouth, South Africa Border Cave, South Africa Omo I (Kibish), Ethiopia Herto,Ethiopia Singa, Sudan Jebel Irhound 1? Morocco 130 kya Not completely modern, but very close Big brow ridge Omo Kibish? Omo I Omo Kibish formation Anatomically modern! Chin! Dated to 195 kya Possibly oldest anatomically modern human remains Herto? Found near Herto village (Middle Awash, Ethiopia) Hence known as Herto man Dated to 160-154 kya Anatomically modern! Just outside envelope of present-day variation Most similar to an Australian aborigine anatomically Named Homo sapiens idaltu by White et al. (2003) Idaltu means Elder in the Afar language Herto? Acheulean and MSA tools Discoverers say it evolved anagenetically from Homo rhodesiensis (i.e., Kabwe 1); Textbook calls this African Homo heidelbergensis Herto man appears right as classic Neanderthals arise in Europe Strong fossil data AGAINST multiregionalism Klasies River Mouth? South African coast caves Lots of AMH bones Skhul and Qafzeh? First non-African AMH, ~100 kya Found in what is now Israel Clearly modern anatomy Co-existed with Neanderthals Thought to have died off or retreated back into Africa Unsuccessful migration Region had highly variable climate, often inhospitable Serially re-colonized? Neanderthals,AMH,Neanderthal,... Qafzeh IX? Vertical forehead Reduced brow Canine fossa Definite chin Small anterior teeth Middle East? First destination outside of Africa, ~60kya Unclear where we entered though Climate Precise timing of migration Northern Dispersal Route Southern Dispersal Route Australia? No Homo erectus or heidelbergensis known in Australia AMH remains from Lake Mungo Contentious dating As young as ~30kya or as old as ~50kya (Bowler et al. 2003) Genetic evidence corroborates 50 kya East Asia? Multiregionalists see East Asian traits as evidence of continuity ??smaller face and teeth flatter cheeks rounder foreheads less prominent noses shovel-shaped incisors However, these traits could be homoplasies Product of similar selective forces (specific to E Asia) on both H. erectus and H. sapiens Or product of genetic drift Additionally, not corroborated by other types of data (e.g., mtDNA or nuclear genome sequence data) Cro-Magnon I? Les Eyzies, France 32 kya Exact migration route into Europe unknown Earliest Europeans Arrive as Neanderthals on way out Dolni Vestonici (Moravia)? Upper Paleolithic Site ca. 30-25,000 years old structures, activity areas, burials, grave goods, ritual symbolic behavior Mitochondrial DNA? Mitochondrial DNA (mtDNA) is maternally inherited Both males and females inherit it from mother Only females pass it on. No recombination! All modern humans share a mitochondrial common ancestor The mitochondrial Eve, 150-200kya in Africa Non-Africans are clearly a subset of Africans Models of Human origins (mtDNA)? Clear separation of human mtDNA Modern Human-Neanderthal mtDNA divergence ~350-700 kya The mtDNA + the timing of earliest African AMH = Fact that Homo sapiens and Homo neanderthalensis are separate and sister species Neanderthal Introgression? Advent of the Neanderthal nuclear genome slightly changed the story Neanderthal draft genome sequence compared to genomes from: the San, the Yoruba, (African) the Han Chinese, Papua New Guinea, and France (Non-African) Neanderthal genome slightly more similar to non-Africans than Africans Not unique to any specific non-African groups Later studies with more populations confirmed this First estimated 1-4% introgression in non-African genomes Neanderthal Introgression? Draft genome sequenced primarily from Vindija, Croatia (40 kya) and also from Mezmaiskaya (65 kya) Higher quality genome from proximal toe phalanx from Denisova cave in the Altai Mountains (>50 kya) Neanderthal Introgression? introgression has been dated 47-65 kya Higher introgression found in East Asians than Europeans Statistically unclear if South Asians are intermediate or same as Europeans Introgression revised to 1.5-2.1% with new sequence data Not absolutely clear where introgression occurred Other introgression? Denisovans are an unknown populations (or species?) related to Neanderthals Little morphological data Other than an LM3 and a 5th distal phalanx Found in Denisova Cave in Siberia Modern Oceanians have 3- 6% Denisovan introgression End result, models of origin? Trace DNA to Africa ~150 kya All have different small bits from other places What this means for out of Africa? Analogy: Replacement model (Out-of-Africa) is regular coffee Continuity model (Multiregionalism) is decaffeinated coffee (~10% caffeine content) The new Introgression models are like a cup of coffee with ~95% the caffeine of a regular cup Can you call that cup regular or decaf? Does the name you call it change what it is? The name you give it does not matter, it is the numbers that reflect the reality. Human variation and the race question? Homo sapiens is a polytypic species. Homo sapiens is genetically homogeneous. Explaining human diversity? 1) Adaptationist Approach Variation is a result of natural selection 2) Historical Approach Variation reflects patterns of population history Genetic Structure of Human Populations; Rosenberg et al (2002)? 377 highly variable regions of the human genome studied 1056 individuals from 52 populations worldwide ?? Results: 93-95% of variation within groups 3-5% of variation between groups only 8% of alleles regionally exclusive of these, median frequency is 1% Genetic Diversity of Human Populations; Jobling et al? Branch lengths proportional to genetic distance Space occupied by taxon is proportional to genetic diversity Humans genetically homogeneous by hominoid standards Genetic Diversity of Human Populations; Prunolli? Diversity as a function of geographic distance Race: biology or culture? Cultural, but conceptualized biologically. Blood and race are symbolically intertwined Classification schemes serve social purposes Race constructed from arbitrary physical characteristics Skin color, hair color, skin, height, etc. To function socially, must be categorical and simple Race vs Ethnicity? Conceptions of ethnicity temporary & temporal Religious & political symbolism maintain cultural heritage no necessary connection to biological conceptions Race and Ethnicity Confusion of biology and culture mixing and substitution of terms Ultimately incongruent Racial Classification Schemes? USA Hypodescent (the one drop rule): classifies into minority group Brazil racial classification is not fixed (individuals can change it) still based on skin tone system recognizes more physical variation (500+ race labels) class status (money whitens) South Africa (Apartheid Era) Black, White, Coloured, Indian Population Registration, Group Areas Acts (1950) Pencil test Linnaeus: systema naturae? (1758) Typological approach to race identifying types within Homo sapiens Homo europaeus Homo afer Homo asiaticus Homo americanus Johann Blumenbach? 5 human races Ethiopian Caucasoid Mongoloid American Malay Earnest a. Hooten? American physical anthropologist Non-adaptive traits explain real differences between races. 3 primary races 7 composite races 15 sub-races Carleton Coon? 1962 5 races Homo sapiens threshold crossed multiple times Some races evolved before others Stanley Garn? 9 geographical races Amerindian Polynesian Micronesian Melanesian Australian Asiatic Indian European African Phenotype and Race? Environmental factors -temperature ,altitude, sunlight Socio-cultural factors -diet & nutrition, health care, access to resources Geographic proximity -positively associated with admixture increasingly unimportant since ~1500 Clinal Effect? latitude correlates with darkness of skin Lighter skin: ? vitamin D absorption (prevents rickets); ? skin cancer rates & folate depletion Darker skin: ? vitamin D absorption (prevents hypervitaminosis D, but risk of rickets at high latitudes); ? rates of sunburn, skin cancer & folate depletion; ? frostbite Adaptive Mismatch? Arctic Peoples = darker than predicted Reasons: Recent arrivals (~10kya) Marine diet high in vitamin D The classificatory conundrum? Single traits cant reveal totality of variation Multiple traits undermine stable typology Different trait lists require new schemes Non-metric analysis? Things not measurements Rectangular orbit Wide interorbital area Guttered nasal border S shaped zygmatico-maxillary sulture ?How many individuals possess all the features used to describe a racial type? European- 35% Asian- 51% African- 17% Anthropology and Racism? Racial typologies are argued to be biologically rooted Biological roots mean existing sociopolitical system is inevitable Anthropology has been the formal (academic) arbiter of racial thought Disavowal of pure races is due to Lots of good data Reexamination of old data A desire by biological anthropology to repent for past associations Cultural anthropologists understood this before biological anthropologists Summary denials of population differences are also dangerous Are we still evolving? Cultural adaptation over biological adaptation Culture creates novel environments Environment still impacts biology Levels of adaptation? Adaptation: Genetic (evolutionary) change Time period: generations Adaptability: Developmental change Time: lifetime/childhood Acclimation (acclimatization): Plastic physiological change Time: minutes/hours/weeks Behavioral/cultural Decisions Time: unconstrained Human adaptation? Skin Pigmentation Body Shape & Body Size Hair Form & Pigmentation Skin & Fat Physiology Skeletal Variation Inference of adaptation? 1. existence of a selective agent (environmental stressor) 2. heritability of traits 3. covariation of stressors and traits conferring fitness Circumpolar cold adaptations? Genetic Different levels of vasoconstriction to the extremities protect against frostbite without losing too much heat Cultural Cold water fish are high in essential fatty acids (EFAs) which may increase blood pressure in the fingers High altitude? Stressors Hypoxia (reduced available oxygen) Intense solar radiation Cold Low humidity Wind Developmental Effects Slower maturation Greater lung volume Relatively large heart The Moken Sea Gypsies? Adaptation or Acclimatization? Normal vision on land, but 2X as clear underwater. Other children can be trained to constrict their pupils Unclear if the Moken have a genetic adaptation Lactose Intolerance? Lactose Carbohydrate in mammal milk Lactaseenzymeallowsustodigest AdultIntolerance Diarrhea, Cramps, Flatulence LactasePersistentAllele(autosomaldominant) Bacteria!!!Make them do the work prevlant in china, south Africa, American Indians, African americans The pima? ~ 50% of adults have Type II Diabetes Genes Thrifty genotype Hypothesis adaptation for starvation Environment Low incidence in traditional subsistence High incidence in affluent environment Biomedical anthropology? -Health and Illness from distinct perspectives 1. Evolution 2. Variation 3. Genetics -Epidemiology 1. Quantitative analysis of disease in populations 2. Interest in patterns rather than particulars

Author Anonymous ID 271247 Card Set What are the two major models of human origin and their supporters.txt Description anthro 21-23 Updated 2014-04-20T22:14:31Z Show Answers