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Formed from interstellar gas and dust. Creates sun.
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Single celled bacteria are the oldest known living organism.
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Can grow larger and reprouduce faster than their competitors.
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Sromatolites create the first extensive reef system.
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oxygen appears in teh environment, causing damage to living tissue.
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Spherical in shape and float ar or near the surface of water.
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Firt of four ice ages.
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Sheild critical factor in the emergence and survival of complex life and land.
Protected organisms from harmful UV rays so they could exsist on land. -
Hag fishes and lampreys are the only jawless fishes alive today.
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Levels of 21 percent by volume of atmosphere.
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Early reptiles share many skeletal similarities with amphibians.
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90 % of all species go extinct.
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Earlyest are rodentline and solitary. Inverebrate genera possible land go extinct.
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Heat from deep within cause the pangaea supercontinent to separate.
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60-80% of all species go extinct.
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Live in trees in tropical or subtropic areas.
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Begain to appear.
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Larger brain cases the most difference from all others.
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Nearly all mammals and birds over 40 pounds go extinct. Partically due to humans over hunting.
