ANTH 1013 1st Edition Lecture 13 Outline of Last Lecture I. Organizing primatesII. Derived anthropoid traitsIII. PlatyrrhinesIV. CatarrhinesV. CercopithecoidsVI. HominoidsOutline of Current Lecture I. Primate behavioral ecologyII. Sexual SelectionCurrent LectureI. Primate Behavioral Ecologyi. Behavior: anything organisms do that involves action in response to internal or external stimuli. The response of an individual, group, or species to its environmentii. Behavioral ecology: the study of the evolution of behavior, emphasizing the role ofecological factors as agents of natural selectioniii. Niche: the sum of the habitat requirements that allow a species to persist and produce offspringiv. What do primates eat and why?a. Categories of primate foods:1. Insects (insectivore)a. Insectivores are small bodiedb. Low availability, high energy content, high nutrient content, medium ease of processingc. Molar shape: long crests on molars, good for shearing chitind. Large incisors and canines, long crests on molars, short, simple gute. Primates lack the specialized adaptations of large-bodied insectovores2. Fruit (frugivore)a. Frugivores are medium bodiedThese 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.b. Medium (seasonal) availability, high energy content, low nutrient content, easy processingc. Molar shape: rounded cusps and short crests, good for crushing brittle fruitsd. Large incisors, round cusps and short molar crests, short, simple gut3. Leaves (folivore)a. Folivores are large bodied b. High availability, medium energy content, medium nutrient content, difficult to processc. Molar shape: long crests on molars, good for shearing cellulosed. Small incisors, long crests on molars, long, complex gutb. Kay’s threshold:1. Smaller than 500 grams: fruit + insects2. Larger than 500 grams: fruit + leavesv. Why do primates move about in different ways?a. Leaping: 1. Vertical clinging and leaping2. Quadrupedal leaping (saltation)3. Morphological characteristics: very long hindlimbs, long spines, powerful grasping hands and feet – hindlimbs are longer in primates that VCLb. Quadrupedalism: 1. Terrestrial quadrupedalisma. Longer limbs for long stepsb. Short, strong digitsc. Stronger, less flexible joints2. Arboreal quadrupedalisma. Shorter limbs for balanceb. Powerful grasping hands on feet for holding onc. Large tail for balance3. Knuckle-walkinga. In great apes only (chimps/bonobos, and gorillas, not orangutans)c. Suspension:1. Brachiation2. Bridging3. Morphological characteristics: very long forelimbs, very long and curved hand bones – phalanges, ribcage is wide from side to side, very mobile arm joints (shoulder elbow, and wrist)d. Body Size:1. Balance:a. Small primates balance more easily on top of branches – tend to be arboreal quadrupedsb. Large primates find balancing on top of branches more difficult – are more commonly suspensoryc. Small animals are less likely to be injured if they fall, and aremore likely to leapd. Small primates encounter more gaps that they can’t reach across – must leap more oftene. Most primates realize the consequences of falling if you are large, and don’t leap… or even climb that muchf. Large primates can bridge many gaps – must leap less often2. Predators:a. Terrestrial primates encounter more predators, and tend to be largerb. Arboreal primates encounter fewer predators, and tend to be smallervi. What kinds of groups do primates live in and why?a. Social system: the grouping in which a primates species lives, including its size and compositionb. Types of primate social systems:1. Monogamya. One adult female and one adult malei. Ex: gibbons (hylobates) and titi monkeys (callicebus)2. Polygynya. One adult male and multiple adult femalesi. Ex: gorillas3. Polyandrya. One adult female and multiple adult males:i. Ex: callitrichines4. Multimale/multifemalea. Multiple adult females and malesi. Ex: baboons (papio) and geladas (theropithecus)5. Noyaua. Males and females solitary but in overlapping rangesi. Ex: orangs (pongo) and bushbabies (galago)6. Fission-fusiona. Multiple males and females in a group, but with frequent changing of group compositionc. Why live in a group at all? 1. Predator defense:a. Advantages: selfish herd effect, alarm calls, mobbingb. Disadvantages: predator attraction2. Resource defense:a. Advantages: displace smaller groupsb. Disadvantages: have to share resourcesc. Resource distribution and group size:i. Many small patches: small group size, small home rangeii. Fewer large patches: large group size, large home range3. Mate acquisition:a. Advantages: greater access to potential matesb. Disadvantages; competition for access to matesII. Sexual Selectioni. What limits an individual’s reproductive success?a. Problem: access to mates, survival of offspringb. Solution: seek many mates, paternal investmentii. Sexual selection: selection arising as a result of preference by one sex for certain characteristics of the other sexa. A special case of natural selection in which traits are favored because they enhance an individual’s ability to gain access to matesb. “Selection depends, not on a struggle for existence, but on a struggle between males for possession of the females; the result is not death to the unsuccessful competitor, but few or no offspring.” – Charles Darwiniii. Intersexual selectiona. Female choosiness leads to intersexual selection. Differential mating success of members of one sex due to preferences of members of the opposite sex for certain phenotypesiv. Male-male competitiona. Consequences of physical competition can be obvious:1. Body size dimorphism2. Canine dimorphismb. While other types of competition, such as sperm competition, are not as obvious:1. Testes dimorphismc. Consequences:1. Monagamy: M—M competition low; F promiscuity low2. Polygyny: M-M Competition very high; F promiscuity low3. Multi-male/multi-female: M-M competition high; F promiscuity very highv. Sperm competitiona. Competition between sperm of two or more males for the fertilization of an ovum. Is more pronounced in species with high female promiscuity (copulating with more than one male)vi. What is the most common mating system among primates?a. POLYGYNY – females have access to quality males, male has access to numerous femalesvii. What is the LEAST COMMON mating system among primates?a. POLYANDRY – happens