Part 3 How are INDEX fossils MOST HELPFUL

Part 3 How are INDEX fossils MOST HELPFUL?

ALL fossils tell us about our biological (life) past…

ALL fossils tell us about our biological (life) past…

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

ANY cast, mold, petrified, carbonized, trace fossil can tell us our BIOLOGICAL past. Original remains (mummified, frozen, preserved tissue, amber -- DNA) 2. Molds (rock IMPRINT/impressions of once living) 3. Casts (sediment fill up a mold…making 3 -D statue) 4. Petrified (HARD minerals replace cells!) 5. Trace (records the ACTIVITY of plant/animal) 6. Carbonized (very thin layer of DARK carbon covers the rock) 1.

ANY cast, mold, petrified, carbonized, trace fossil can tell us our BIOLOGICAL past. Original remains (mummified, frozen, preserved tissue, amber -- DNA) 2. Molds (rock IMPRINT/impressions of once living) 3. Casts (sediment fill up a mold…making 3 -D statue) 4. Petrified (HARD minerals replace cells!) 5. Trace (records the ACTIVITY of plant/animal) 6. Carbonized (very thin layer of DARK carbon covers the rock) 1.

ANY cast, mold, petrified, carbonized, trace fossil can tell us our BIOLOGICAL past. Original remains (mummified, frozen, preserved tissue, amber -- DNA) 2. Molds (rock IMPRINT/impressions of once living) 3. Casts (sediment fill up a mold…making 3 -D statue) 4. Petrified (HARD minerals replace cells!) 5. Trace (records the ACTIVITY of plant/animal) 6. Carbonized (very thin layer of DARK carbon covers the rock) 1.

Original remains (mummified, frozen, preserved tissue, amber -- DNA) 2. Molds (rock IMPRINT/impressions of once living) 3. Casts (sediment fill up a mold…making 3 -D statue) 4. Petrified (HARD minerals replace cells!) 5. Trace (records the ACTIVITY of plant/animal) 6. Carbonized (very thin layer of DARK carbon covers the rock) 1. BUT, IF ANY ONE OF THESE FOSSILS CAN HELP US FIND OUR GEOLOGIC HISTORY…

What part of a book shows you where to find specific things in the rest of the book?

What part of a book shows you where to find important things in the rest of the book?

Original remains (mummified, frozen, preserved tissue, amber -- DNA) 2. Molds (rock IMPRINT/impressions of once living) 3. Casts (sediment fill up a mold…making 3 -D statue) 4. Petrified (HARD minerals replace cells!) 5. Trace (records the ACTIVITY of plant/animal) 6. Carbonized (very thin layer of DARK carbon covers the rock) 1. Those fossils have a special name. ANY FOSSILS THAT CAN HELP DATE OUR GEOLOGIC HISTORY IS AN INDEX FOSSIL.

Match: 1. Rock cores 2. Ice cores 3. Fossils 4. Index fossils A. Meteorlogic (climate) past B. Biologic past C. Geologic past

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

INDEX fossils help us find layers of rock from 2 different continents.

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

#2 layer shows INDEX FOSSILS!

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

Like a BOOK’s INDEX helps you find things inside a big book! INDEX FOSSILS HELP US FIND THE IMPORTANT LAYERS ON DIFFERENT CONTINENTS.

INDEX FOSSILS MUST MEET 2 CRITERIA: 1. THEY NEED TO BE WIDESPREAD OR REGIONAL? 2. THEY NEED TO HAVE BEEN AROUND MORE OR LESS YEARS?

INDEX FOSSILS MUST MEET 2 CRITERIA: 1. THEY NEED TO BE WIDESPREAD! 2. THEY NEED TO HAVE BEEN AROUND MORE OR LESS YEARS?

INDEX FOSSILS MUST MEET 2 CRITERIA: 1. THEY NEED TO BE WIDESPREAD! 2. THEY NEED TO HAVE BEEN AROUND A RELATIVELY SHORT TIME.

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

GOOD INDEX fossils are great…COVER the 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(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 widespread but existed briefly. 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 layers!

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

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!

Any general type of fossil can be an INDEX fossil if it helps us DATE the ROCK 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!

Any general type of fossil can be an INDEX fossil if it helps us DATE the ROCK LAYERS!

Any general type of fossil can be an INDEX fossil if it helps us date the rock layers! RELATIVELY AND ABSOLUTELY

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