ANT 102 1st Edition Lecture 11Outline of Last Lecture I. Detailed overview of previous lectureOutline of Current Lecture I. Norm of reactionII. Survival of the fittestIII. Reproductive strategies IV. What makes a mammal a primateCurrent LectureNorm of ReactionGenotype: genetic (allelic) make-up of one or more gene lociSS, Ss, ss; SsTt, ssTt, SSttPhenotype: expression of a particular allele, physical characteristicsTall, brown hair, O blood typeNorm of reaction: variation in the expressed phenotype based on environmental contributions Survival of the fittestFitness: success of an individual organism in passing on its traits to future generationsBecoming a grandparent, or great grandparent Fitness vs reproductive successNatural selection does not necessarily maximize reproductive success, it optimizes itThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.r/K reproductive strategies“r selection”: produce many offspring with little parental investment Coral“K selection”: produce few offspring, but with high parental investmentMonkeys  Class Mammalia: the mammalsHomoeothermic: warm blooded. Maintaining constant body temperature internally opposed to ectothermicHair/fur for insulation Heterodonty: differential teeth (incisors, canines, premolars, molars), not homodonty4 chambered heart (separates oxygenated blood from de-oxygenated blood)Mammary glands: produce milk for offspringMostly vertically oriented limb morphology for efficient locomotionNon-continuous growthThree inner ear bonesStrong olfactory and tactile (vibrissae, aka whiskers) adaptation (larger forebrain)Modified feeding apparatusOnly one bone on each side of jawHeterodontyTeeth only replaced onceIncreased range of motion in chewingTrends in mammalian evolutionReduction in dental formulaWay of measuring degree of homodonty/HeterodontyDental formula for humans: 2/1/2/3Early primates have 2/1/3/3Reduction in functional dactyly (pentadactyly)Ten fingers, ten toes, other organisms slowly lose digits over timeSpecialization of the digestive systemHow do we distinguish primates at an ordinal level?What is a primate?Hard to diagnose: primate features tend to be primitive and generalizedMore useful to discuss evolutionary trends of modern primatesEvolutionary trends in modern primatesSenses and brain More reliant on vision than olfaction (short face, reduction or loss of vibrissae, color vision)Orbital convergence (stereoscopic vision)About 1/3 of our vision is an overlap (left eye vision and right eye vision)Postorbital barExpansion and increased complexity of brainModification of the brainIncreased visual area in brainColor visionDogs see in shades of grays, blacks, browns, etc. Binocular stereoscopic visionReduced olfactory regions (olfactory lobe)Enhanced encephalization: increased sizeMore about brainsPrimates have large brains for their body sizeMonkeys have larger brains than strepsirrhines (prosimians)Chimps have even larger brainsHumans have enormous brainsBrain size seems related to diet (higher quality vs lower quality diets)Frugivores (meaty eaters) vs folivores (leafy eaters)EyesPrimates have forward facing eyesAdaptation for catching insectsNocturnal primates have large eyesTapetum lucidum in strepsirrhinesThe reason your pet’s eyes light up in the darkUnlike most other mammals, vision generally much more important that smellOld world monkeys and apes have trichromatic color visionHumans have large whites of eyesEasier to see eyes in the distance Facial expression communicationMaintaining social cuesSkullShortening of face and nose (rostrum)Larger cranial capacityCranial base flexure (kyphosis)Sensory trendsReduced importance of scentLoss of naked rhinarium (wet nose)Shortening of snout (rostrum)Reduction of olfactory area brainReduction of scent glandsIncreased importance of visionBetter color visionMore visual signalsHairPrimates are generally coveredHumans covered, but mostly vellus, very fine and softOften have bold markings on their hairFaces, hands, bottoms usually bareHair and bare skin both contributeFacesMonkeys and apes have bare facesFacial expression an important part of social communicationFaces often have colorful markings and hair tuftsBeards, mustaches, wild hairdosAppendages Modification of the hand and foot for grasping, manipulating and sensory acuityOpposable thumbs and big toesNails, not clawsTactile pads: concentration of nerve fibers and blood vessels at tips of fingers and toes for tactile acuityEvolutionary trends in modern primatesLimbs and locomotionGeneralized skeletonTendency toward upright postureFlexible, generalized limbs (retention of clavicle, rotating forearms)Positional repertoire Positional rep: the way an organism holds and moves its bodyPrimates cling and leapPronograde vs orthogradePronograde: vertebral column held horizontally, long and narrow thorax (esp at shoulder) indicates committed quadrupedalismOthrograde: vertebral column held vertically, shorter and wider thorax (esp at shoulder) indicates suspensory or bipedal behavior NichesPrimate arboreal Insectivores, gummivores, frugivores, foliviresInsects-sap-fruits-meatsLater there is a broader arboreal and terrestrial adaptationGenitalsMany primates have brightly colored genitalia Females have sexual swelling to signal fertilityReproductive traits and featuresOne pair of nipples (always pectoral)Pendulous penis and scrotal testes (always visible, never hidden inside body)Long gestation periodSmall litter sizeBehavioral trendsStrong mother-offspring bondGregarious and social animalsPrecocious (well developed)Increased child dependency, increased parenting behavior (strong “K selection” strategies)Long life expectancy Behavior tendencies DiurnalAborealIntelligentMother-offspring bondKinship is importantOrganized along matrilines (female lineage)Social and