Fossils can tell us about our biological life

Fossils can tell us about our biological (life) past…

FOSSILS can tell us about our BIOLOGICAL PAST. We’d have to build stronger refrigerators.

How can FOSSILS help tell us Earth’s GEOLOGIC history?

How can FOSSILS help tell us Earth’s GEOLOGIC history? When they are INDEX FOSSILS!!!

INDEX fossils can be any type of fossil, BUT these help us DATE the ROCK LAYERS… SPECIAL!!

REMEMBER HOW WEGENER LINED UP FOSSILS FROM ACROSS CONTINENTS TO SHOW THE PLATES WERE CONNECTED?

Some fossils help us line up layers of rock from 2 different continents.

We call these INDEX FOSSILS!

Like a BOOK’s INDEX helps you find things inside a big book!

GOOD INDEX fossils need to be

GOOD INDEX fossils need to be 1. …on more than one continent

GOOD INDEX fossils need to be 1. …on more than one continent 2. but only in 1 layer

GOOD INDEX fossils need to …cover more than 1 continent on Earth but are only in 1 layer so we can compare and line up rock layers around the world.

INDEX fossils are great! They around many places but only briefly in 1 layer so we can compare and line up rock layers around the world.

Which fossil is only found in a single layer over time & place?

Which fossil(s) would make the best index fossils?

Why isn’t the fossil in layer “b” a good index fossil?

Why isn’t the fossil in layer “b” a good index fossil? It’s not found all over the place.

Index fossils are _ _spread but existed _ _ _ly. index fos sils are in a th layer AN D ALL OV in ER

Index fossils are widespread but existed briefly. index fos sils are in a th layer AN D ALL OV in ER

INDEX fossils help DATE Earth’s GEOLOGIC layers!

tiered activity…

Which fossil below would make the best INDEX FOSSIL? T I M E P E R I O D S

Would fossils of cockroaches make for good index fossils? 49 million year old cockroach fossil.

Would fossils of cockroaches make for good index fossils? 125 million year old cockroach fossil.

Would fossils of cockroaches make for good index fossils? Cockroaches would NOT make good index fossils. They are widespread, but have existed for hundreds of millions of years in many different layers!

Say humans were destroyed by a plague. Millions of years from now, aliens found human fossils buried deep under Earth, would fossilized humans be good index fossils?

Say humans were destroyed by a plague. Millions of years from now, aliens found human fossils buried deep under Earth, would fossilized humans be good index fossils? YES! Were we widespread over Earth? YES. Did we exist briefly? YES

Human trace or remains would make GREAT index fossils because we have only been here for a few thousand years but have been all over the planet!

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