ch 25 - history of life on earth
- University of Minnesota - Twin Cities
- Biology 1009
- ch 25 - history of life on earth
Last Modified: 2012-04-24
Related Textbooks:Biology with MasteringBiology™ (with WebCT Access Code Card -- Generic) (8th Edition)
- Early earth probably had an atmosphere made mainly from nitrogen and hydrogen gas and very little oxygen gas
- One theory holds that the atmosphere contained clouds of H2S, NH3 and CH4 creating a reducing environment. From this environment, the formation of carbon based molecules tat we associate with life required little energy to form.
(535 to 525 million years ago) marks the earliest fossil appearance of many major groups (phyla) of living animals. animals are now hunters, not scavengers of algae/ etc like before.
due to: cool climate and shallow seas, volcanic eruptions made cooler climate from particulates, asteroid releases particlates that block out the sun
Can take millions of years for diversity to recover following a mass extinction
Can pave way for adaptive radiations
- Any of the master regulatory genes that control placement and spatial organization of body parts in animals, plants, and fungi by controlling the developmental fate of group of cells.
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