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Unformatted text preview: (cyanobacteria) producing oxygen When is life thought to have arisen? 3.5 billion years ago Explain plate tectonics? study of continental movement; theory that continents had once been joined together and drifted apart; driven by destruction of old and creation of new because of convection currents What is the rate of continental drift? 2.5 centimeters per year What is Rodinia? Supercontinent of Canada & USA; desolate & lifeless; triggered snowball earth (the biggest freeze earth has ever seen) What is thought to have happened 700 million years ago? Rodenia broke up and created a green house effect with the release of CO2 earth turned into a snowball What is the Cambrian explosion? Highest oxygen levels and explosion of life; lots of new species developed What is the importance of the Burgess shale quary? Rich fossil location When is the ozone layer thought to have formed? 400 million years ago...
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- Spring '07