Evolution: change in allele frequencies from generation to generation

Modern synthetic theory explains evolution as occurring in two stages:

First stage: microevo processes = mutation, recombination, genetic drift, and gene flow produce and redistribute genetic variation

Genetic drift: evolution due to chanceGene flow: evolution due to gene exchange between populations

Second stage: macroevo processes like natural selection act on variation over geologic time causing speciation

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Quiz concerns

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Today: Anthropoids

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Last time: prosimians and tarsiers

monkeys, apes, humans

Traits distinguishing the anthropoids from prosimians...

-increased parental care-more mutual grooming

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Anthropoids

-85% of all primate speciesDivided geographically: New World monkeys and Old World monkeys

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Monkeys

Where: Central and South America-almost exclusively arboreal-prehensile tail

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New World Monkeys

Tamarins and marmosets-smallest monkeys-claws (ancestral trait)-twin births-males more involved in infant care

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New World Monkeys (example)

Where: Africa to Southeast Asian islands-sexual dimorphism-females have swelling and redness during estrus

Divided into subfamilies: Cercopithecines Colobines

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Old World Monkeys (Cercopithecidae)

Baboons, mandrills, and macaquesWhere: Africa and AsiaDiet: omnivorous

Traits-terrestrial baboons have ischial callosities

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Cercopithecines

Colobines Where: Africa and AsiaDiet: folivorous

Traits-leaf-eating monkeys-segmented stomachs

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Old World Monkeys: Colobines

Traits distinguishing them from monkeys

Continued evolutionary trends:-longer infant developmental periods-more complex brains and behavior-larger body size and brainier-shortened trunk-arms longer than legs-no tail

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Hominoids: apes and humans

Where: tropic areas of southeast AsiaDiet: omnivorous

Brachiation: suspensory locomotion involving arm swinging

Traits: adaptations to brachiation-muscled shoulders-long arms-curved fingers

https://youtu.be/U3JhwjNfx_g13

Gibbons and siamangs

Where: forests of Borneo and SumatraDiet: frugivorous

Traits-almost completely arboreal-solitary

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Orangutans

Where: Africa (east/west lowland, and mtn gorillas)Diet: vegetarians

Traits-largest living primates-sexual dimorphism

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Gorillas

ChimpanzeesWhere: equatorial AfricaDiet: omnivorous plus other animals

Traits-knuckle-walking on ground-brachiation in trees

Social: large fluid communities-form lifelong attachments

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Hominoids

BonobosWhere: areas south of Zaire RiverDiet: omnivorous

Traits-copulate throughout estrus cycle-female-centered communities-female-female and male-male sexual behaviors

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Hominoids

Homo sapiensWhere: found everywhere in all climatesDiet: omnivorous

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

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Hominoids - humans