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Further Investigations: Change Over Time

  1. Choose a mass extinction event from SF Table 7.2, and research its consequences.
  2. Investigate an extinct animal species. Describe the physical features of this species, when it lived and how it is related to modern-day animals.
  3. Research how geologists use index fossils to identify different geologic periods. What characteristics make a “good” index fossil? What are some of the index fossils associated with specific periods of time in Earth’s history?
  4. Scientists have found fossilized marine coral in Tibet, a country in the Himalayan Mountains. Explain how marine organisms can appear high on continental mountains, far from the ocean.


SF Table 7.2. Table of mass extinction events by date and their possible causes
Date Event Name Level of Extinction Possible Cause
0.01 mya Quaternary 55% of large mammal genera End of ice age, hunting by early humans
66 mya Cretaceous-Paleogene 17% of families, including dinosaurs; 50% of genera; end of Age of Reptiles Asteroid impact, volcanic eruption
205 mya Triassic-Jurassic 23% of families; 48% of genera Breakup of Pangaea, extensive volcanic eruptions
252 mya Permian-Triassic 70% of all land species; 80-96% of marine species; end of Paleozoic era Formation of Pangea leading to depletion of shallow seas, volcanic eruptions, glaciation
345 mya Late Devonian 19% of families, 50% of genera Glaciation, meteor impact
450 mya Ordovician-Silurian 25% of families, 57% of genera Glaciation, causing changes in sea level


Exploring Our Fluid Earth, a product of the Curriculum Research & Development Group (CRDG), College of Education. University of Hawaii, 2011. This document may be freely reproduced and distributed for non-profit educational purposes.