Announcements

(Again) Midterm and Essay 1 = April 12th, Thursday the week after Spring Break

This week: More chapter 5 - classification practice, new species concepts, fossils

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-native to tropics and semi-tropics (little seasonal variation in temperature)

Four categories of Primate traits - homologies found in most primate groups

1. Limbs and locomotion; 2. Diet and dentition; 3. Senses and brain; 4. Maturity and behavior

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Overview of the primates

Rhesus macaque

1. Limbs and locomotion

-tendency towards hold their bodies erect

-flexible generalized limb structure

-prehensile hands and feet

-opposable thumbs

-retention of 5 digits

-nails instead of claws on some digits

-tactile pads on digits3

Overview of the primates

2. Diet and dentition

-generalized dentition; omnivorous

Dental formulas:

Us and Old world monkeys: 2:1:2:3

New world monkeys: 2:1:3:3

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Overview of the primates

3. Senses and brain

-color vision and diurnal

-stereoscopic vision - eyes are located in front of face

-decreased reliance on sense of smell

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Overview of the primates

4. Maturity and behavior

-long life span

-long gestation period

-reduced number of offspring

-delayed maturation, i.e., grow up slowly

Behavior-greater dependency on learned, flexible behavior rather than pre-packaged instinct

-social groups with permanent association of males6

Overview of the primates

Ancestral primate traits

Question: What can we infer about the strategy and environment of the first primates?

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Overview of the primates

Question: What can we infer about the strategy and environment of the first primates?

Arboreal hypothesis: many primate traits can be explained as adaptations to living in trees

Visual-predation hypothesis: many primate traits can be explained as adaptations to hunting insects in the lower tiers of the rainforests millions of years ago.

Flowering plant hypothesis: primate traits developed the same time flowering plants (angiosperms) spread across the globe and diversified.

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Three hypotheses explaining primate adaptations

Lemurs and lorises - suborder Strepsirhini-most ancestral living primates

Shared characteristics-retention of ancestral reliance on olfaction (sense of smell)

rhinarium: moist, fleshy pad on most mammalian noses (enhances ability to smell)

-shorter gestation and maturation period-dental specialization: dental comb: used for grooming and feeding-found on Madagascar larger lemurs = more derived = diurnal; diet of vegetablessmaller lemurs = more ancestral = nocturnal and insectivorous 9

Survey of living primates

found on the islands of Southeast Asia

Shared characteristics-nocturnal-insectivoreshttps://youtu.be/gGsKDjvwVM8-enormous immobile eyes-head can rotate 180 degrees

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Tarsiers

Traits shared by all anthropoids - distinguish them from lemurs and lorises-larger body size-larger brain relative to body weight-reduced reliance on smell; 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 speciesTwo groups divided geographically: New World monkeys and Old World monkeys

New World MonkeysFound in Central and South America-all are diurnal (except owl monkeys)-almost exclusively arboreal

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Anthropoids: monkeys apes, humans

Tamarins and marmosets - smallest of all monkeys-claws instead of nails-twin births-mated pairs = social group-males more involved in infant care

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Anthropoids: monkeys apes, humans

Old World MonkeysHabitats range from tropical forests to semiarid deserts…

-most are quadrupedalAll belong to Cercopithecidae family-subfamilies: Cecropithecinae and Colobinae-most are arboreal; some spend more time on ground have an ischial callosities-exhibit sexual dimorphismfemales during estrus have swelling and redness

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Anthropoids: monkeys apes, humans

Old World Monkeys

Cercopithecines - baboons and macaquesCharacteristics-more generalized compared to colobines-mostly omnivorous-mostly in Africa (except macaques)

Colobines - African colobus monkeys and Asian langursCharacteristics-narrower diet - eat mainly leaves

Ischial Callosities: tough leathery pad cercopithecines on their hindquarters

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Anthropoids: monkeys apes, humans

Old World Monkeys

Colobines - African colobus monkeys and Asian langursCharacteristics-narrower diet - eat mainly leaves

Segmented stomachs aid in digesting leaves more efficiently

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Anthropoids: monkeys apes, humans

Characteristics distinguishing hominoids from monkeys-larger body size-no tail-shortened trunk (more stable lower back)-arms longer than legs (except in humans)-more complex behavior and brain-increased period of infant development-diet largely fruit with leaves, flowers, and insects

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Hominoids - apes and humans

Gibbons-fastest brachiatorshttps://youtu.be/U3JhwjNfx_g-curved fingers, muscled shoulders

OrangutansBorneo and SumatraCharacteristics-almost completely arboreal-sexual dimorphism

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Hominoids - apes and humans

GorillasAfrica: eastern lowland, western lowland, and mountain gorillas

Characteristics-largest primates

sexual dimorphism: 400 pound males vs 200 pound females-primarily terrestrial-'knuckle-walkers'

Social organization: natal group-almost exclusively vegetarian

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Hominoids - apes and humans

ChimpanzeesFound in 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

BonobosFound in areas south of Zaire River

Characteristics~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 all over the world in every climate

-generalized features like the other apes-omnivorous

Characteristics-only living bipeds-entirely dependent on culture-brainsize increased enormously

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Hominoids - humans