15.4: Understanding Earth's History- Challenge 1

1. Why are the La Brea Tar Pits in Los Angeles, California, an exception?

they formed under unusual circumstances

2. Hard-shelled marine organisms ___ more often than organisms with soft tissues in exposed environments.

fossilize

3. Amber is ___.

fossilized tree sap

4. When insects fossilize, it is usually in ___.

amber

5. A bone dissolves and leaves behind a space in a rock called a ___, which fills with minerals to form a ___in the original shape of the organism.

mold; cast

6. ___ can be used to identify a specific period of time.

Index fossils

7. At the time of the fossilization of coal, the temperature of Antarctica was ___.

warm

8. Compared with fossils in younger rocks, fossils in older rocks are ___.

less similar to modern organisms