GEOLOGIC TIME
GEOLOGIC HISTORY
• Determined by major characteristics in the Earth’s
surface, climate, and types of organisms
ERA:
• A unit of geologic time that contains two or more
periods
PERIOD:
• A unit of geologic time that is longer than an
epoch, but shorter than an era
EPOCH:
• A unit of geologic time that is longer than an age
but shorter than a period
ERAS & PERIODS
ERAS, PERIODS, & EPOCHS
AGE OF THE EARTH
• 4.6 Billion Years Old
PRECAMBRIAN ERA:
• 4.6 Billion to 542 Million Years Ago
• 88% of the Earth’s History
• Very little is known because rock l...
PALEOZOIC ERA:
• 542 Million to 251 Million Years Ago
• Continents went from separate to Pangea during
this time period
• ...
MESOZOIC ERA:
• 251 million years to 65.5 million years ago
• Continents begin to drift apart
• Age of Reptiles, including...
CENOZOIC ERA:
• 65.5 million years ago to Present
• Temperatures decreased
• Age of mammals
• Fossils of first humanoids b...
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11. geologic time notes

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11. geologic time notes

  1. 1. GEOLOGIC TIME
  2. 2. GEOLOGIC HISTORY • Determined by major characteristics in the Earth’s surface, climate, and types of organisms
  3. 3. ERA: • A unit of geologic time that contains two or more periods
  4. 4. PERIOD: • A unit of geologic time that is longer than an epoch, but shorter than an era
  5. 5. EPOCH: • A unit of geologic time that is longer than an age but shorter than a period
  6. 6. ERAS & PERIODS
  7. 7. ERAS, PERIODS, & EPOCHS
  8. 8. AGE OF THE EARTH • 4.6 Billion Years Old
  9. 9. PRECAMBRIAN ERA: • 4.6 Billion to 542 Million Years Ago • 88% of the Earth’s History • Very little is known because rock layers have been eroded and deformed by plate tectonics • Period during which the atmosphere and as a result life originated
  10. 10. PALEOZOIC ERA: • 542 Million to 251 Million Years Ago • Continents went from separate to Pangea during this time period • Far richer in plant and animal life • Vertebrates such as fish, reptiles, and amphibians developed • 90% of marine and 70% of land life died at end of era
  11. 11. MESOZOIC ERA: • 251 million years to 65.5 million years ago • Continents begin to drift apart • Age of Reptiles, including dinosaurs • Mass extinction at end, possibly by an asteroid • Flowering plants begin to develop
  12. 12. CENOZOIC ERA: • 65.5 million years ago to Present • Temperatures decreased • Age of mammals • Fossils of first humanoids began to develop

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