Fossils

Cornell Notes pg. 137

What is a Fossil?

• Preserved remains or traces of plants, animals, and other organisms.

Types of Fossils:

1. mold fossils (an impression made in the rock- like a footprint in sand)

2. cast fossils (formed when a mold is filled in)

3. trace fossils = (fossilized nests, burrows, footprints, etc.)

4. true form fossils (fossils of the actual animal or animal part).

Where are fossils found?

• Almost always in Sedimentary Rocks as rocks layers are uplifted to the surface.

• Ice, amber

The Fossil Record

• Totality of fossils (discovered and undiscovered) and their placement in the rock layers

• Used to show ancestral relationships between organisms

• Used to tell us about the history of the Earth

How do we know the age of a Fossil?

• Position in rocks layers- where are the oldest layers?

• Radioactive Dating- Radiocarbon Dating: uses proportion of Carbon-14 to Carbon-12 to determine age of organic material.