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What does it mean to be biologically human?. Why are we such strange apes? January 24, 2005. “Carl” Linnaeus Classification system Hierarchical Binomial Genus species. Taxonomy. Human Taxonomy. Kingdom Animalia Animal Phylum Chordata Chordates
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What does it mean to be biologically human? Why are we such strange apes? January 24, 2005
“Carl” Linnaeus Classification system Hierarchical Binomial Genus species Taxonomy
Human Taxonomy Kingdom Animalia Animal Phylum Chordata Chordates Subphylum Vertebrata Vertebrates Class Mammalia Mammals Infraclass Eutheria Eutherians Order Primates Primates Suborder Anthropoidea Anthropoids Infraorder Catarrhini Catarrhines Superfamily Hominoidea Hominoids Family Hominidae Hominids Genus Homo Humans Species Homo sapiens Subspecies Homo sapiens sapiens
Why look at primates? • Homologies: • Genetics • Brain Structure • Biochemistry • General physiology
Why look at primates? • Analogies: similar traits that arise if species experience similar selective forces and adapt to them in similar ways. • Feeding ecologies of terrestrial primates
Major Primate Characteristics • Grasping • Tactile Hands • Vision (stereoscopic) • Brain Complexity • Parental Investment • Sociality
What do non-human primates look like? • Prosimians • Lemurs • Tarsiers • Bushbabies • Loris • Aye Aye
What do non-human primates look like? • New World Monkeys • Spider Monkey • Squirrel Monkey • Capuchin Monkey • Marmoset • Howler Monkey
What do non-human primates look like? • New World Monkeys have prehensile tails.
What do non-human primates look like? • Old World Monkeys • Baboons • Macaque • Langurs • Proboscis • Drills, Mandrills
What do non-human primates look like? • “Lesser” Apes • Gibbons
What do non-human primates look like? • “Great” Apes • Orangutan • Gorilla • Chimpanzee • Bonobo • Humans
Primates in Macroevolutionary Context • Misconceptions: • Evolution is not teleological! • Diversity does not represent stages • All animals are equally “modern” • Evolution does not necessarily lead to smarter, stronger, or morally superior animals.
Evolutionary relationships among species (“family tree”) Phylogeny
Homologies between species. Ancestral Traits
Derived Traits • Compared to non-human primates, humans have: • Less fur • More technology • Bipedal Locomotion
What do non-human primates teach us? • Insights into fossil primates • Activity Patters (nocturnal, diurnal) • Locomotion • Quadrapeds, Knucklewalkers, Brachiators, Bipeds • Diet/Feeding Ecology • Insectivores, frugivores, folivores, carnivores, omnivores
What do non-human primates teach us? • Feeding Ecology • Sexual Dimorphism • Mating Strategies • All Related
What Females “Want” • Offspring to survive • Reliable food supply • Help raising offspring
What Males “Want” • Sex (pass on genes=maximize fitness) • Avoid helping raise offspring when it interferes with further mating
Feeding Ecology and Mating • Females map onto food resources • Males map onto females
Food Clumps Easy for females to defend food Easy for males to defend females Result: Monogamy Gibbons
Food dispersed and highly seasonal Females can’t defend resources (nomadic) Males can’t defend females Solitary, nomadic mating Orangutan
Large, dense food patches Multiple females form a territorial group One male can protect the group One male polygyny Gorillas
Food is densely distributed and plentiful No need for territoriality for females or males Multi-male polygyny Chimpanzees
Sexual Dimorphism • Differences in body size between males and females • Highest when there is high competition between males for mates • In humans, suggests that sometime in pre-history humans were polygynous
Sexual Dimorphism • Monogamy: No Dimorphism • Multi-male polygyny: mild • Solitary mating: medium • Single male polygyny: extreme