| Term | Definition |
|---|
| Era | the larger of the two subdivisions of earth's history |
| Period | subdivision of eras |
| Precambrian Era | 4.6 million - 545 million years ago |
| Precambrian Era | Oldest, longest era, land is formed 4.6 billion years ago by volcanoes |
| Precambrian Era | Bacteria and green algae forms during this time |
| Paleozoic Era | 545 million years ago – 250 mya |
| Paleozoic Era | Vertebrates appear (fish, and other animals that have a backbone) |
| Paleozoic Era | Then amphibians form (can live outside of water but lay eggs in water such as frogs |
| Paleozoic Era | All continents come together in one big land mass called Pangaea |
| Paleozoic Era | Largest mass extinction at the end (most living things die) |
| Mesozoic Era | 250 mya – 65 mya |
| Mesozoic Era | “The age of reptiles” (reptiles are cold blooded, have scales, lay eggs) |
| Mesozoic Era | The first birds and dinosaurs appear |
| Mesozoic Era | Ends in another mass extinction called the KT event that kills dinosaurs 65 million years ago which gives rise to mammals |
| Cenozoic Era | 65 million – present day |
| Cenozoic Era | “age of the mammals” (born alive, have hair or fur, young are fed milk, warm blooded) |
| Cenozoic Era | homo sapiens appear (that’s people) |
Combine with other sets
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