Unit 12Change Over Time

How the fossil record is used to attempt to show evidence

of animals changing over time.

Seasons can show change over time

Skeleton of a dog.

Skeleton of a bulldog.

Law of Superposition

Older

Newer

Coelacanth as a fossil

Coelacanth alive today.

Sharks alive today

Sharks preserved as a fossil

Other “living” fossils

• Uniformitarianism doesn’t explain how we find soft-tissue animals in the fossil record.

• Slow deposition over time simply takes too long

• Soft bodied animals like jellyfish would be either rotted away or eaten by scavengers.

• Catastrophism can explain how a jellyfish can be fossilized.

Some thoughts….

In order for a fish giving birth to fossilized, it has to be covered instantly with sediments, at the moment it occurs.

In order for a fish eating a fish to fossilized, it has to be covered instantly, at the moment it occurs.

This is a trilobite and the tracks it made just prior to be covered up by a massive and sudden amount of

sediments!