11/1/2017110/31/17 Humans as just another primate species (Hunter-Gatherers)1Topics for Today• Understanding the life of a hunter-gatherer, as a human vs. as a chimpanzee.– Central place foraging– Reciprocal altruism• Human mate choices: panhuman universals vs. cultural specifics.• Diversity among human mating systems• The human pair bond211/1/20172Why study Human Hunter-Gatherers?• What are the selective constraints acting on humans living as hunter-gatherers?• What makes humans unique as primates, compared to other hunter-gatherers?3Hunting-and-gathering or Foraging• Living off of wild resources.• Until 10,000 years ago, how all people lived.• Until 5,000 years ago, how 90% of people lived.• Today, how very few people live and they are in the most marginal environments.• Homo sapiens show up 200,000 years ago411/1/20173Contemporary Forager Groups• Ache and other groups: Rain forests, South America• Agta: Philippines• Inuit: Arctic areas• Australian aborigines: Western Desert• Hadza: Savanna/woodlands, Tanzania• Efe (Pygmy) foragers and Lese (Village horticulturists): IturiForest, Congo• “Bushmen” (Ju/’hoansi, !Kung, Basarwa, San): Kalahari Arid Lands, southern Africa5Ju/’Hoansi of the Kalahari (Namibia, Botswana, South Africa)611/1/20174Mobility1. Residential mobility over very large yearly home range.2. Central place foraging each day, with delayed consumption = innovation of logistic mobility3. Fission-Fusion of nuclear families based on seasonality of food & water (not like Pan’s daily fission-fusion)7Kalahari: in dry season, foragers clump around permanent waterholes (n!ore)811/1/20175Sexual Division of Labor:Sharing food!!!!9Mongongo nuts, the staple of the diet1011/1/20176Women Gather Plant Foods: high diversity and quality, over 100 species of plants, compared to low quality of agricultural diets (but high quantity).11Foraging with Children: you must carry the child as well as the food.1211/1/20177131411/1/20178Hunting for MeatMen hunt.More protein, higher calories than plants.BUT less reliable due to low density of this scarce resource.Must share hunting success or die.15No long-term storage of surplus means little ability to use surpluses for social favors. Therefore, no specialization of skill sets.16Foragers rarely experience mass starvation events, but there is daily uncertainty in the food supply11/1/20179If no investment in things, you invest in PEOPLE: Hxaro Exchange System17Being Social, “Minnesota Nice,” and Altruism• “Nice is Nice”: the Group Selection Argument (Wynne-Edwards).• “Nice is often Nepotism”: the Kin Selection argument (Hamilton).• “I’ll be nice to you if you are nice to Me!”: the Reciprocal Altruismargument (Robert Trivers)1811/1/20171019Conditions for Reciprocal Altruism1) the opportunity to interact often (better in longer-lived organisms with low dispersal rate).2) the ability to keep track of support given and received (to recognize each other). 3) the ability to provide support only to those who help them (to deny cheaters).19Dracula was a nice guy: Reciprocal Altruism in Vampire Bats20Conditions for Reciprocal AltruismTit-for-tat Game TheoryThe Prisoner’s Dilemma2011/1/201711Modern Humans Living ChimpsLast Common Ancestor(LCA)T I M E21Industrial, Agricultural, & Foraging HumansLiving ChimpsLast Common Ancestor(LCA)T I M E2211/1/201712Human Mate Preferences23Human Mate Preferences• Cultural influences on mate choice– Chastity varies cross-culturally– Good financial prospect shows cross-cultural uniformity2411/1/201713Evolved Behaviors: Inbreeding Avoidance• Human universals– Inbreeding avoidance– Psychological mechanism?• Edward Westermarck effect• Adults not attracted to those they grew up with25Evolved Behaviors: Inbreeding Avoidance“Minor marriages” in parts of China2611/1/201714Social Consequences of Mate Preferences• Nyinba– Himalayas– Fraternal polyandry• More likely to dissolves if:– More than three husbands– Youngest brother younger than the wife272811/1/201715ALA#9: What type of mating system do chimpanzees practice?a. Monogamy b. Polygynyc. Polygynandryd. Polyandrye. None of the above29Text 20583 plus your answer to 14352154567ALA#10: What type of mating system do gorillas practice?a. Monogamy b. Polygynyc. Polygynandryd. Polyandrye. None of the above30Text 20584 plus your answer to
View Full Document
Unlocking...