How do Fossils Form?

How do Fossils Form?

Learning about Ancient Organisms and Habitats

Review - Observing Fossils

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• When an organism dies, it decomposes, or breaks down.

• Fossils are what is left behind when the organism has decomposed.

• We can make inferences about organisms and habitats from long ago by observing fossils.

Multiple Choice

Fossils are made when an organism ___ after it dies.

• Buries itself underground

• Decomposes

• Teleports

Multiple Choice

How can we learn about organisms that died millions of years before we were born?

• Study fossils

• Use a time machine

• Read old textbooks

Multiple Choice

When we look at fossils, we can learn about ____.

• Habitats only

• Organisms only

• Organisms and Habitats

Multiple Choice

When we look at fossils, we _____ about the organism and its habitat.

• Need to make inferences

• Learn everything we need to know

Multiple Choice

You are out walking and find this fossil.

What habitat do you infer used to be here?

• Arctic

• Desert

• Ocean

• Grassland

Multiple Choice

You are out walking and find this fossil.

What habitat do you infer used to be here?

• Arctic

• Desert

• Ocean

• Grassland

Multiple Choice

You find a bunch of fossils of the same kind of lizard in one location.

The best inference is ___.

• The lizards lived in groups.

• The lizards lived alone.

• Somebody dropped a pile of fossils together

Multiple Choice

You observe fossilized bird poop full of mouse hairs.

The best inference is ___.

• Birds used to be covered in mouse hair.

• The bird must have pooped on a mouse's den.

• The bird probably ate mice.

Multiple Choice

You observe the skull of an organism with flat teeth.

The best inference is ___.

• The teeth were flattened by rocks over time.

• The organism used to eat mostly plants.

• The organism used to eat mostly meat.

Match

Match the tooth shape to the organism's diet.

• Sharp teeth

• Flat teeth

• Sharp and flat teeth

Only meat

Only plants

Plants and meat

• Only meat

• Only plants

• Plants and meat

Open Ended

"I infer that this organism ate ____ because I observe _____."

How Fossils are Formed

• ​Most organisms are eaten before they can form fossils.

• When organisms do form fossils:

  • 1) They die.

  • 2) They are buried.

  • 3) Their soft parts decompose.

  • 4) Their hard parts turn into rock.

• This process takes thousands to millions of years.

Multiple Choice

When most organisms die, ___.

• They become fossils

• They do not become fossils.

Multiple Choice

Where do organisms turn into fossils?

• In the treetops

• On the ground's surface

• Buried underground

Multiple Choice

When fossils are formed,

the soft parts of an organism, like the skin and organs, will ____.

• Turn into rock

• Decompose

• Get eaten by vultures

Multiple Choice

When fossils are formed,

the hard parts of an organism, like the teeth and bones, will ____.

• Turn into rock

• Decompose

• Get eaten by vultures

Multiple Choice

Which part of an organism is most likely to decompose?

• Teeth

• Bones

• Organs

Multiple Choice

Which parts of an organism are most likely to turn into rock?

• Skin and Hair

• Bones and Teeth

• Heart and Lungs

Multiple Choice

How long does it take for an organism to form a fossil?

• Ten to One Hundred Years

• Thousands to Millions of Years

• Billions or Trillions of Years

Reorder

Sequence these events required to form a fossil.

• Die.

• Be buried.

• Soft parts decompose.

• Hard parts turn into rock.

1

2

3

4

• 1
• 2
• 3
• 4

Open Ended

The steps for forming a fossil are:

1) ____, 2) Be ____, 3) Soft parts ______, 4) Hard parts _____.

Body Preservation

• In some situations, the soft parts do not decompose and we can see the whole organism.

• Keeping everything the same is called preservation.

• Organisms are preserved when they are buried very fast in ice or amber.

• In preserved organisms, we can see their hair, skin, and organs, not just their bones.

Multiple Choice

When an organism is preserved, the soft parts ____.

• Decompose

• Turn into rock

• Stay the same

Multiple Choice

When all parts of the organism stay the same for millions of years,

we say the organism is ____.

• Preserved

• Fossilized

• Decomposed

Multiple Choice

Organisms are likely to be preserved when surrounded by ____.

• Mud and sand

• Water and snow

• Ice and amber

Multiple Choice

How do we know what woolly mammoth fur looked like?

• Woolly mammoths were preserved in ice.

• Woolly mammoths were preserved in amber.

• We made an inference based on fossilized bones.

Open Ended

A scientist describes exactly what an ancient organism's heart looked like.

Was this organism likely covered in mud or amber?

"I think this organism was covered in ____ because ______."