Fossils

What are fossils? A trace or the remains of a living thing that died a long time ago.

Amber fossil

Trace fossils

Some fossils look like the actual parts of the animals such as bones and teeth. Minerals replace the bones slowly.

Cast & mold A mold is the shape of a living things, left in the sediment when the rock formed. A cast forms when mud or minerals later fill a mold. It has the same shape of the living thing.

amber

Trace

Trace

amber

How a fossil forms? 1. soft parts of an animal decompose 2. Hard parts such as shells or bones are buried under layers of sediments. 3. Over long time the bones and sediment turn to rock. 4. Movement of Earth’s crust moves the rock closer to the surface. Wind and rain wear away the rock. Then people can see the fossil.

What do we learn from fossils. To learn about animals and plants that no longer live on Earth What kind of food animals ate by looking at the shapes of their teeth Also from fossils we can know what a place was like long time ago, for example fossil clams in a place show that a sea once covered the area.