Science dr – Flashcards
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How much geologic time do the layers of rock exposed at grand canyon national park represent
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2 billion years
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How many years of earths history do geologists study
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4.6 billion years
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Why have geologists created the geologic tine scale
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Its standard method that divides earths history into parts
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The eon during which the earliest known rocks formed on earth
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Archean
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The eon in which we live in
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Phanerozoic
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The eon from which scientists have found rocks and meteorites only from the moon
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Hadean
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The eon in which the first oganisms with well developed cells appeared
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Proterozoic
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What do the boundaries between geologic time intervals represent
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Shorter intervals in which visible changes took place on earth
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Te fourth largest division of geoligic time
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Epoch
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The largest division of geologic time
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Eon
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It includes 2 or more periods
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Era
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The third largest division of geologic time
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Period
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What os extinction
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Te death of every member of a species
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Describe the beginning of the paleozoic era
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Marine life flourished
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How did the paleozoic era end?
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With the largest mass extinction in earths history
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Why is the mesozoic era called the age of reptiles
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Birds and small mammals began to evolve
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Represents geologic time
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Fossil record
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What era are we in now
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Cenozoic era
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Why is the cenozoic era called the age of manmals
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Mammals flourished
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What probabley caused te extinction of the dinosaurs
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Global climate change
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What unique trait probabley helped mammals survive
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Regulating body temperatures internally and bearing young that develope inside the mother
