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16 Cards in this Set
- Front
- Back
2 Phases That Life Emerged on Earth
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1) chemical evolution
2) biological evolution |
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chemical evolution
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evolution of the organic molecules, biopolymers, and systems of chemical reactions needed to form the first protocells (1 billion years)
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biological evolution
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evolution from single-celled prokaryotic bacteris to single-celled eukaryotic creature, and then to multicellular organisms (3.7-3.8 billion years)
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The cosmic dust that condensed into earth turned molten from:
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1) meteorite impacts
2) heat produce by radioactive decay of chemical elements in its interior |
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Chemicals that dominated the primitive atmosphere:
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1) cabon dioxide
2) nitrogen 3) water vapor 4) other - methane, ammonia, hydrogen sulfide, hydron chloride |
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organic molecules needed for life formed from inorganic chemicals found in earth's primitive atmosphere under the influence of readily available:
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1) energy from electrical discharges (lightning)
2) heat from volcanoes 3) intense ultraviolet (UV) rays 4) other forms of solar radiation |
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Other possibilities are that necessary organic molecules formed:
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+ on dust particles in space and reached the earth on meteorites or comets
+ formed deep within the earth + formed around mineral-rich and very hot hydrothermal vents |
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hydrothermal vents
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vents that sit atop crack in the ocean floor leading to subterranean chambers of molten rock
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protocells
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small globules that could take up materials from their environments and grow and divide (much like living cells)
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reactions that formed protocells could have occured:
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1) in the earth's warm shallow waters
2) deep within the earth 3) around thermal hydrothermal vents on the ocean bottom |
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fossils
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mineralized or petrified replicas of skeletons, bones, teeth, shells, leave,s and seeds, or impressions of such items
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other sources of fossil information:
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1) chemical and radioactive dating of fossils
2) nearby ancient rocks 3) material in cores drilled out of buried ice 4) the DNA of organisms alive today |
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biological evolution / evolution
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the change in a population's genetic makeup (gene pool) through successive generations
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theory of evolution
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all species descended from earlier, ancestral species
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microevolution
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the small genetic changes that occur in a population
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macroevolution
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used to describe long-term, large-scale evolutionary changes through which
1) new species are formed from ancestral species 2) other species are lost through extinction |