Anthro 103 Exam #2 Review SheetNatural SelectionPrimatesMammals with grasping hands, large brains, high degress of learned rather than innate beaviorOrder of Primates is divided into two suborders: Strepsirhini and HaplorhiniStrepsirhines should not be considered more primitive than haplorhineshaplorhine ( Haplorhini): Infraorder of the order Primates that includes the anthropoids and the tarsier.Tarsiers, monkeys, apes, humansstrepsirhine ( Strepsirhini) Infraorder of the order Primates that includes the prosimians, excluding the tarsier.Lemurs, lorises, and galagoesPrimate body plan is GENERALIZED, not specializedGives then versatility: most primates engage in a wide variety of modes of travel from arm swinging to running, leaping and walkingAll non human primates are quadrapeds, designed for moving while using all four limbs, but there is a great variation in the way they use their limbsGrasping Hands with opposable thumbs or big toesBelieved to be the fundamental primate adaption, although not all completely possess this traitMost have 4 digits per hand and foot, and have the ability to grasp objects with a greater precision than many other mammalsNonhuman primates have an opposable hallux (big toe)Colobine monkeys, gibbons and spider monkeys – the four fingers are so long and the thunb is so short, the cannot grasp wellFlattened NailsThe primate grasping hand has flattened nails at the end of the digits instead of clawsTrue for all primates except for the marmosets and tamarinsMany Strepsirhines have a combination of nails and single clawed digit on their hands and feetForward Facing Eyes and Steroscopic VisionStereoscopic view enables excellent depth perceptionOverlapping fields of vision = 3 dimensional viewFour Primate TrendsAdaptation to arboreal lifeGrasping hands and feet, opposable thumb and big toeReliance on sightPost orbital barStereoscopic vision – depth perception, acute vision, ability to focusColor visionUnspecialized dentitionCusps are low, roundedVariable dietsGreater dependence on learning as opposed to instinctWe have to spend a lot of time socializingLarge brains relative to body size – capacity to learnExtended juvenile periodsArboreal HypothesisHypothesis for the origin of primate adaption that focuses on the values of grasping hands and stereoscopic vision for life in the treesFrederic Wood-Jones and George Elliot-Smith, England 1920’sWidely accepted until challenged by Matthew Cartmill in the 1970’sNoted that squirrels thrive in trees but do not possess these qualitiesVisual Predation HypothesisHypothesis for the origin of primate adaption that focuses on the value of grasping hands and stereoscopic vision for catching small prey.Cartmill – 1970’sSupportFossil records show that early on, primates were anatomically similar to modern insectivoresMany predators have forward facing eyes – eagles, cats, owls, etc.Generalized TeethTeeth shape can tell a great deal about a species from diet to mating systemMost nonhuman primates diet: leaves, fruit, other plant products, occasional animal protein in form of insects or small animalsThey do not have big canine teeth for tearing food like carnivores do, nor heavy grinding molars like grazing mammals haveThey have gone through and evolutionary reduction in specialization of teeth: evident in small canines and incisors and rounded molarsDental Formula: The parabolic arc the forms the upper or lower row of teethTwo incisorsOne canineTwo PremolarsThree MolarsExceptions: New world monkeys have a 3rd premolar; and strepsirhines have varying dental formulasPetrosal BullaTiny bit of skeleton that covers and protects parts of the inner earSingle bony trait that is shared by all primates, living or extinct, that occurs in no other mammalian groupPost orbital BarEye sockets go all the way aroundProtects the eye more effectively than the open orbit of lower mammalsMore complete in haplorhines than strepsirhinesSingle OffspringNearly all primates give birth to single offspringSmaller species may give birth to litters or twinsSingle births, long maturation period, and strong maternal investment replaced more primitive pattern of litters with less intensive careLarge BrainsNeocortex – Part of the brain that controls higher cognitive function; the cerebellum; larger volume in primatesLarger brains more evident in haplorhines than strepsirhinesMore ridges in brains surface in haplorhines = higher cognitive functionExtended OntogenyOntogeny – life cycle of an organism from conception to deathPrimates are notable for their extended length in each life stageThis is because primates must learn in order to survive in the worldFind food and waterLive in a social groupParental investmentDiurnalActive during daylight hours; possess color vision; limited olfactory sensesAll haplorhines except for Aotus monkey are diurnalNocturnalRely on their sense of smell to negotiate their physical and social environmentMany Strepsirhines are nocturnalThe StrepsirhinesLemurs, Lorises and GalagoesTooth comb – Incisor teeth protrude from the front of the mouth to form a comb like surface used for groomingLemursSuperfamily LemuroideaFound only on MadagascarMade up true lemurs, dwarf lemurs, sifakas and indri, and the aye-aye.Adapted to the habitats of MadagascarLorisesDiverse group of strepsirhines found in tropical Africa and AsiaInclude various species of galago (bush baby) that are found only in AfricaResemble most primitive ancestors of modern haplorhinesNocturnal, solitaryEat fruits, insects, small animalsThe HaplorhinesNonhumans include Tarsier, New World Monkeys, Old World Monkeys, apes and hominids.Possess the full suite of adaptations that characterize the living primatesGuided more by seeing than hearingFull closure of back of eye orbitsLower jar that is fused at the midline in adulthoodDiurnal with exception of owl monkey and tarsierLive in social groups with exception of oranutanRatio of brain to body size is higher than in strepsirhinesCognition related to social complexityIncludes all extinct forms of hominids as well as humansTarsiersLive in IndonesiaOwl like ecological role as nocturnal predators on small vertebrates, most highly carnivorous or all non human primatesLive in monogamous pairs; exclusively nocturnalNew World MonkeysMarmosets, Spider MonkeysClassified in the infraorder platyrrhini and are all in the superfamily CeboideaLive in tropic forests of western hemisphere: South AmericaSmall body sizeThree