ANTH 260 - UNIT 2 STUDY GUIDEPRIMATESGENERAL TRAITSUpright posture, 5 digits on hands and feet (flexible nails not claws, opposable thumb/big toe, tactile pads on finger tips), collarbone for mobile front limbs, different dentition/teeth equations, reduced emphasis on smell, orbital eye with color vision, primate history traits (few offspring per pregnancy, prolonged period of infancy & dependency, long lifespan for body size, learned behavior, large social groups)EVOLUTIONARY EXPLANATIONSArboreal Hypothesis: basic primates selected to fit an adaptive niche in the treesVisual Predator Hypothesis: primates adapted to forest ground to catch small insects & preyFruit Flower Eating Hypothesis: favored by selection to better harvest flowering plants & fruitSURVEY OF 4 GROUPS Prosimians - Locomotion vertical clinging and leaping- Mostly eats insects, but also birds, bats, snakes- Confined to Madagascar, tropical Africa and Asia- Greatest number of ancestral traits of all primates- EXAMPLES: Lemurs, Tarsiers, Lorises, Aye-Ayes IndrisNew World Monkeys (Platyrhini)- Anthropoid (higher primate, close to humans)- Small and have prehensile (grasping) tails and run on top of branches- Spend a lot of time in trees so they live in tropical forests of Central & South America- Large multi-male, multi-female groups- EXAMPLES: Woolly Monkey, Spider Monkey, Squirrel Monkey, Howler Monkey, Owl Monkey, Pygmy marmosetOld World Monkeys (Carcopithecoidea)- Anthropoid - Cercopithecines: partly terrestrial, omnivorous, live in large groups- Colobines: arboreal, colorful, feed on leaves- EXAMPLES: Baboons, Macaques, Mandrills, Languars, Vervet Monkey, etc. Hominoids- Anthropoid- “Great Apes”o Chimpanzee (Africa equator, knuckle-walkers, groups lead & defended by males competing for status, important mother-infant bond, Jane Goodall studied them,use tools for meals and hunting)o Bonobo Chimpanzee (taller, longer arms, darker faces, less aggressive, larger female group role, sex a lot for anything)o Gorilla (Africa equator forests, sexual dimorphism in body size, one-male and multi-female groups, mostly vegetarian)o Orangutan (rainforests of Borneo and Sumatra, large tree climbers, smaller socialgroups, frugivorous - eat mostly fruits)- “Lesser Apes”o Gibbons and Siamangs (tropical SE Asia, pair bonded adults and offspring, brachiation - swing like monkey bars, long arms & fingers, short legs)PRIMATE BEHAVIORAL ECOLOGY: REPRODUCTIVE STRATEGIESBEHAVIORAL ECOLOGYNatural selection favors strategies that increase fitnessStrategy: a set of behaviors that produces a particular course of action under certain conditions- No perfect strategy, doesn’t imply conscious reasoning or intentFEMALE AND MALE REPRODUCTIVE STRATEGIESFemale success: related to ability to obtain calories and nourishment for herself and offspring- Transportation, warmth, protection from danger also very importantMale success: affected more by access to females than to calories resulting in competitionMALE COMPETITIONBeing more attractive, beating up the competition, favored sexual dimorphism (traits that differ between the sexes in a species), sperm competition, infanticide (killing infants) PRIMATE BEHAVIORAL ECOLOGY: EVOLUTION OF COOPERATIONSOCIAL INTERACTIONS+ - Selfish: improves own fitness at the detriment of others+ + Mutualistic: both parties cooperate to get mutual benefit- + Altruistic: actor does something that decreases own fitness, to benefit someone else- - Spiteful: goes out of the way to knock another down, but pay a cost as well, both worse off PROBLEM OF ALTRUISMPoses an evolutionary problem, acts are costly to self at the benefit of othersEXAMPLES: alarm calls, territorial defense, food sharing, communal care of youngSOLUTIONSSocial interactions must be nonrandom (similar characteristics); towards other altruistsKin Selection (Hamilton 1964): o assumes that altruism is underwritten by genes to pass ono Hamilton’s Rule: rb > c R = relatedness or probability that 2 individuals have same allele(high value with parents, closer to 0 with non-kin) B = benefit to recipient (# of additional offspring result) C = cost to the altruist (# of fewer offspring result)Multilevel Selection (Wilson 1975):o When groups with greater frequency of altruists out compete groups with fewer altruists. o Can only occur when variation between groups is greater than variation within groupsReciprocal Altruism (Trivers 1971): o Altruists take turns giving and receiving benefits, without cheaterso This requires opportunities to act in different roles, being able to keep track of what’s given and received, only help those who provided help in the pastFOSSILSCOMPONENTS OF PALEOANTHROPOLOGYPaleoanthropology- multidisciplinary pursuit seeding to reconstruct and explain the timing and nature of evolutionary change in the morphology and behavior of our hominin relatives. Geography- Continental drift: the movement of large tectonic plates (0-100 mm per year) on top of denser rocks beneath Paleoclimatology- climatic conditions of the past analyzed from cores of the earth (usually from deep sea)- Paleomagnetism: movement of the magnetic north pole TAPHONOMYThe study of how fossils and the fossil record form.Fossilization/mineralization: process by which organic material is replaced by minerals, creating a stone copy of the organic originalThese are rare because few conditions allow this formation (rapid burial in fine sediment, gentle burial, mineral-rich chemical environment)DATING TECHNIQUESRelative Dating: - Place finds in a sequence relative to one another, but provide no actual dates or date range- Stratigraphy and the law of superposition: older layers overlain by more recent yearsRadiometric/Absolute Dating:- provides date estimates (in years before present, BP) for geological deposits- Ex: stopwatch analogy- Radiocarbon datingo C12: stable, doesn’t decay, same amount in organism dead or alive as C14o C14: decays through time, created constantly until deathEVOLUTIONEARLY PRIMATESMiocene (23-5 mya): hominoid radiation, “planet of the apes”, world became cooler & drier during latter half, climate change shows shift in primate species (more monkey, less ape), sets the stage for appearance of hominins, Asia and Europe- Dryopithecus (9.5 mya): teeth chimp-like in size and enamel indicating frugivory, craniumand skeleton ape-like, brachiation locomotion (swings branch to branch)- Sivapithecus (14-8 mya): big powerful jaws, large molars