Mesozoic Era (Age of the Dinosaurs)

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Mesozoic Era(Age of the Dinosaurs)

• 225,000,000 years ago to 65,000,000 years ago
• Warm Climate
• Three Periods
• Triassic
• Jurassic
• Cretaceous

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Triassic Period (225-180 MYA)

• Pangaea (supercontinent) formed

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Triassic Period (225-180 MYA)

• First Dinosaurs (small in size)

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Triassic Period (225-180 MYA)

• Conifers and Cycad Forests Dominate (Gymnosperms)

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Jurassic Period (180-135 MYA)

• Pangaea starts to separate

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Jurassic Period (180-135 MYA)

• Dinosaurs Dominate Allosaurus, Diplodocus,
  Brachiosaurus, Stegasaurus.

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Jurassic Period (180-135 MYA)

• Reptiles in the sea - Icthyosaurs 8 m
  Plesiosaurs 15 m.

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Jurassic Period (180-135 MYA)

• 1st mammals (small rodents).

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Jurassic Period (180-135 MYA)

• 1st birds (Archaeopteryx).

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Cretaceous Period (135-65 MYA)

• Continents in modern positions

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Cretaceous Period (135-65 MYA)

• Dinosaurs still dominate T. rex (carnivore)
  Triceratops (horned) Trachadon (duck-billed)

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Cretaceous Period (135-65 MYA)

• Angiosperms (flowering plants with fruit) evolve
  dominate

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Cretaceous Period (135-65 MYA)

• Mass Extinction 50 of all plant and animal
  groups die
• Alvarezs Meteor Impact Theory- iridium layer
  (common in meteors), dust blocked out the sun.

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Cenozoic Era(Age of the Mammals)

• 65,000,000 years ago to Present Day
• Two Periods
• Tertiary
• Quaternary

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Tertiary Period (65 MYA to 1.8 MYA)

• Warm and humid climate
• Mammals dominate increasing in size
• Angiosperms (flowering plants) dominate
• Grasses develop, grazing animals become even
  larger
• Earliest prehistoric humans (approximately 3.5
  MYA).

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Animals of the Tertiary
Organisms that have been found in the La Brea tar
pits of Los Angeles
Megatherium, a giant ground sloth (20 ft long).
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Animals of the Tertiary
Indricotherium, measured up to 13 ft at the
shoulder.
Diatryma, a giant predatory bird.
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The Great Ice Age
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Quaternary Period (1.8 MYA to Present)

• The Great Ice Age, ice sheets covered 30 of
  all land
• Land ice bridges connected many continents
  allowing animal migration
• North American elephants (mastodons, mammoths),
  giant sloths armadillos, and saber-toothed cats
  go extinct.
• Modern humans evolve, maybe causing the above
  extinctions from hunting.

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A Sixth Mass Extinction?

• Are we the cause of a sixth mass extinction that
  is currently taking place?
• Round Table Discussion