Science+Test+Review

Review for Unit C Chapter 3 Test Know the definitions of the following words: Mold Cast fossils trace fossils

Be able to identify a __trace fossil__ Ex: tracks, burrows, droppings, and worm holes __Petrified fossils__ occur when wooden material in a tree is replaced with minerals, Most __fossils__ can be found in __sedimentary rock__. They are important because they tell us what Earth was like long ago, and how they have changed over time. Scientists can also infer how an animal moved by studying its footprints.

Sometimes chemical and physical changes take place as remains become fossils. Heat and pressure may destroy most of the buried remains, leaving a thin film called a __carbon film__.

Scientist can learn a lot about an animal by studying its coproplites. Coprolites are animal droppings that have become fossils.

Scientist can find out the age of rock from particles that have decayed. They measure the amounts of the original particles and the new particles that form and compare these amounts.