Paleozoic era (570-225 mya) -first vertebrates emerged -first - - PowerPoint PPT Presentation

Paleozoic era (570-225 mya)

• first vertebrates emerged
• first mammal-like reptiles
• Pangaea formed

Mesozoic era (225-65 mya)

• Age of dinosaurs

Cenozoic era (65-0 mya)

• Age of mammals

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Continental drift: movement of continents on Earth's surface

• plate tectonics moved organisms around the globe during the

Paleozoic and Mesozoic eras

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Mesozoic to Cenozoic

Late Mesozoic era: Age of Dinosaurs

• earliest mammals

Cenozoic era: age of the mammals

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Three modern mammalian subgroups

Monotremes: most ancestral mammals, e.g., they lay eggs

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Three modern mammalian subgroups

Marsupials: immature birth; development continues in mother's pouch

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Three modern mammalian subgroups

Placental: in utero development

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Mammalian shared derived homologies

• Endothermic
• Heterodont dentition
• Placental
• Complex brains and

flexible behavior

• native to tropics and semi-tropics

Four categories of Primate homologies

• 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

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Overview of the primates

• 2. Diet and dentition
• generalized; omnivorous

Dental formulas:

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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
• few offspring
• delayed maturation

Behavior

• depend more on learned, flexible behavior over pre-packaged instinct
• highly social

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Overview of the primates