-
birth of solar system(5 billion years ago)
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earth began to form(4600 million years ago)
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bacteria diversify(3800 Million years ago)
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photosyntheizing bacteria(3700 million years ago)
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oldest fossils(3500 years ago)
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oxygen appears(2200 millionsyears ago)
in the living environment, causing damage to living tissues -
90% species go extinct(250 million years ago)
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mayor glaciation period begins(800 millions years ago)
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protective ozone layer in place(600 millions years ago)
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land plants(480 million years ago)
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oxygen nears present day levels(400 million years ago)
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reptiles(350 million years ago)
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pangaea starts(200 millions years ago)
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primates(60 millions years ago)
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hominds(5.2 million years ago)
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modern humans(100,00 years ago)
