Title
Further Investigations: Change Over Time
Table of Contents
- Choose a mass extinction event from SF Table 7.2, and research its consequences.
- Investigate an extinct animal species. Describe the physical features of this species, when it lived and how it is related to modern-day animals.
- 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?
- 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.
| 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 |
