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Ch 4: Geologic Time
Term | Definition |
---|---|
species | Group of organisms that only reproduce with members of their own group |
cyanobacteria | Earliest form of life. Blue-green algae that photosynthesized. |
gymnosperm | Plants that produce seeds but not flowers. |
angiosperm | Plants that have flowers |
geologic time scale | Divisions of earth's history into time units |
trilobite | Index fossil that has three lobes, and a segmented body |
pangaea | large, ancient landmass that contained all continents. Formed in the Paleozoic and broke up in the Mesozoic. |
Cenozoic | Era of recent life. Began 66 million years ago. |
Paleozoic | Era of ancient life; dominated by fish and ended with a great mass extinction |
Precambrian | Longest time of earth's history. Lasted nearly 4 billion years. |
Mesozoic | Era of middle life. Pangaea broke apart, dominated by reptiles & dinosaurs. |
organic evolution | Changes of organisms over time |
eon | longest subdivision of geologic time |
era | second longest subdivision of geologic time, based on worldwide fossil changes. |
period | These subdivisions are divided into epochs |
epoch | smallest division of geo time. |
natural selection | Process by which only the organism that are suited for an environment will survive. "Survival of the fittest" |