Recall: some important homologies distinguishing the ... Recall: some important homologies distinguishing

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    Primate traits https://youtu.be/BpnlS_ach-0

    Recall: some important homologies distinguishing the primate order:

    *flexible limbs and prehensile hands/feet

    *general dental formula and omnivorous diet

    *color vision, diurnal, depend on vision more

    *delayed maturation/development, more dependence on flexible social behavior and learning

    https://youtu.be/BpnlS_ach-0

  • Question: Since...are all adaptations (traits that evolved in response to the environment), what environmental context best explains why primates acquired all these adaptations?

    -what environment makes color vision a beneficial adaptation?

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    Three hypotheses explaining primate adaptations

  • Visual-predation hypothesis: many primate traits are adaptations to hunting insects in the lower tiers of the rainforests mya.

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    Three hypotheses explaining primate adaptations

  • Flowering plant hypothesis: primate traits developed the same time flowering plants (angiosperms) diversified globally.

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    Three hypotheses explaining primate adaptations

  • Arboreal hypothesis: many primate traits are adaptations to living in trees

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    Three hypotheses explaining primate adaptations

  • Prosimians: Lemurs and lorises -Madagascar

    Ancestral traits -reliance on olfaction

    -rhinarium: moist, fleshy pad on noses -shorter gestation/maturation period -dental comb: used to groom and feed

    Derived traits -smaller lemurs: nocturnal insectivores -large lemurs: diurnal

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    Survey of living primates

  • Southeast Asia islands

    Ancestral -nocturnal -insectivores

    Derived -enormous immobile eyes -head can rotate 180 degrees

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    Tarsiers

  • Anthropoids traits

    -larger body and brain

    -increased reliance on vision

    -longer gestation and maturation periods

    -increased parental care

    -more mutual grooming

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    Anthropoids: monkeys apes, humans

  • Monkeys: 85% of all primate species

    Two groups divided geographically: New World monkeys and Old World monkeys

    New World Monkeys

    Central and South America

    Derived -mostly diurnal -exclusively arboreal

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    Anthropoids: monkeys apes, humans

  • Tamarins and marmosets

    Ancestral traits -smallest monkeys -claws

    -twin births

    -males more involved in infant care

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    Anthropoids: monkeys apes, humans

  • Old World Monkeys -tropical forests to semiarid deserts…

    Cercopithecidae family

    Cecropithecinae subfamily

    Ancestral trasts -sexual dimorphism,

    e.g., females during estrus have swelling and redness

    -quadrupedal

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    Anthropoids: monkeys apes, humans

  • Old World Monkeys -mostly in Africa (except macaques)

    Cercopithecines: baboons and macaques

    -omnivorous -Ischial Callosities: tough leathery pad on hindquarters

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    Anthropoids: monkeys apes, humans

  • Old World Monkeys Africa and Asia Colobines: colobus monkeys and Asian langurs

    -narrower diet of eat mainly leaves

    -Segmented stomachs - digest leaves more efficiently

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    Anthropoids: monkeys apes, humans

  • Characteristics distinguishing hominoids from monkeys

    -larger brains and bodies

    -shortened trunk

    -no tail

    -longer infant development periods

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    Hominoids - apes and humans

  • Gibbons -fastest brachiators https://youtu.be/U3JhwjNfx_g -curved fingers, muscled shoulders

    Orangutans Borneo and Sumatra Characteristics -almost completely arboreal -sexual dimorphism

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    Hominoids - apes and humans

    https://youtu.be/U3JhwjNfx_g

  • Gorillas Africa: eastern lowland, western lowland, and mountain gorillas

    Characteristics -largest primates -primarily terrestrial -'knuckle-walkers'

    sexual dimorphism: 400 lbs males vs 200 lbs females

    Social organization: natal group -vegetarian

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    Hominoids - apes and humans

  • Chimpanzees Equatorial Africa

    Characteristics -anatomically similar to gorillas -knuckle-walking on ground, brachiation in trees

    Diet: variety of plants and animal foods

    Social: large fluid communities; form lifelong attachments

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    Hominoids - chimpanzees

  • Bonobos Areas south of Zaire River

    Characteristics -similar to chimpanzees only less sexual dimorphism

    -includes frequent copulations throughout female estrous cycle

    -stable male-female bonding

    -more frequent sexual activity and sexual activity between members of the same sex

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    Hominoids - bonobos

  • Scientific name for our species:

    Homo sapiens

    -italicize -Genus is capitalized -species lowercase

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    Hominoids - humans

  • Found everywhere in all climates

    -generalized features like the other apes -omnivorous

    Characteristics -only living bipeds

    -entirely dependent on culture

    -brainsize increased enormously

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    Hominoids - humans

  • Behaviors: anything organisms do in response to external/internal stimuli

    Affected by: -genetics

    -environment

    -Instinctual behaviors: fixed behaviors animals born with

    -Plastic behaviors: flexible, learned, and feature prominently in primates

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    Behavior in general

  • Group structure can influence behavior

    Dominance hierarchies -system of social organization ranking individuals by relative access to resources

    -common in primates: resources for male can include access to females

    -ranks are learned and can change

    https://youtu.be/HDxA8-01cp4

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    Social behavior

    https://youtu.be/HDxA8-01cp4

  • Primate social structure influenced by reproductive strategies and behavior

    *Social structures common in primates

    Multi-female, multi-male (most common) e.g., chimpanzees

    Polygyny, i.e., multi-female, single-male (common) e.g., gorillas, baboons

    Monogamy (uncommon) e.g., gibbons

    Polyandry, i.e., single-female, multi-male (least common) e.g., red lion tamarins

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  • Affiliative: friendly relations between individuals; promotes group cohesion

    Grooming - picking debris out of the fur of another individual -reinforces social bonds -most important affiliative behaviors among primates

    Aggressive: conflict between individuals; promotes group separation

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    Group behavior in primates

  • Grooming - picking debris out of the fur of another individual -reinforces social bonds

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    Group behavior in primates

  • Animals use different reproductive strategies to improve reproductive success

    r-selection: relatively large number of offspring; reduced parental care

    K-selection: opposite

    Species either use r or K-selection reproductive strategies

    Females and males in mammals use these reproductive strategies

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    Reproductive behavior - in general and in primates

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  • Primates, like all other animal with complex social behavior compete for good mating opportunities

    Sexual dimorphism: more common in species with high male competition,

    e.g., Orangutan dominant males have pads on face

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    Reproductive behavior - in primates

  • -higher-ranked individuals communicate dominance to lower-ranking, subordinates

    Submission behavior communicates acknowledgement of dominance hierarchy

    E.g., exposing hindquarters to higher-ranks, allowing higher-ranks mount subordinates

    Displays of aggressive behavior communicate rank and maintains group cohesion by reducing violent conflicts

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    Communication

  • -involuntary utterances used to express present emotional states

    Vervet monkeys: specific vocalizations for birds, snakes, leopards Only present tense

    Language and humans: human language is distinct

    -Relies on a set of arbitrary symbols used in written and spoken communication

    -Used to convey abstract concepts like the past and future

    E.g., displacement - communication about objects not currently present

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    Animal communication versus language

  • Primates learn complex social behaviors that resemble our culture

    E.g., in Koko and Kanzi

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    Primate cultural behavior

  • Primates learn complex social behaviors that resemble our culture

    E.g., in Koko and Kanzi

    Both demonstrate the ape capacity to learn to communicate, but lack syntax and grammar like humans.

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    Primate cultural behavior

  • E.g., chimpanzees…

    Stone hammers used across generations

    Variation in tool design seen in different chimpanzee behaviors

    Termite fishing

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    Primate “cultural” behavior

  • E.g., chimpanzees…

    Stone hammers used across generations

    Variation in tool design seen in different chimpanzee behaviors

    Termite fishing

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