The Earth’s History

OBJECTIVE•You will be able to explain theories about

the earth’s past

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Relative

dating

Estimating the age of a fossil by its place in

the layers of the earth (older

towards bottom, newer towards

the top)

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Absolute

Dating

Determining the age of a fossil by the amount

of unstable atoms in it

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Geologic Time Scale

The calendar scientists use to

outline the history of life on

Earth

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extinctWhen a species

dies out completely and

does not reappear

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pangaeaAll the land on

earth connected together that

eventually broke up into the continents

of today

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Plate tectonics

A theory that the earth’s crust

is made of separate pieces

that have moved around

throughout history

ERA WHEN? What was alive? What happened?

GEOLOGIC TIME SCALE

Precambrian

Paleozoic

Mesozoic

Cenozoic