Across
- 2. Hollow impression left behind in rock where an organism once was.
- 4. Solid copy of an organism’s shape, formed when minerals fill a mold.
- 5. When a type of organism completely dies out.
- 6. Preserved remains or traces of plants or animals from long ago.
- 7. Period marked by the sudden burst of many new life forms in the oceans.
- 9. Era when many ocean animals, insects, and the first land plants lived.
Down
- 1. The appearance of new life forms on Earth.
- 3. Period including the Ice Ages and the rise of humans.
- 4. Era often called the “Age of Mammals,” stretching from 66 million years ago to today.
- 8. Era often called the “Age of Reptiles,” when dinosaurs thrived.