Across
- 5. A break in Earth's crust
- 6. A ball of dust, gas, and ice that orbits the sun
- 8. A solid copy of the shape of an organism
- 9. Magma that cools and hardens into a mass of igneous rock
- 10. Long units of time
- 11. A gap in the geologic record
- 12. Its age compared to the ages of other rocks
- 13. A process in which elements release particles and energy
- 15. Lava that hardens on the surface and forms igneous rock
- 16. An animal without a backbone
- 19. A record of the geologicic events and the evolution of life forms as shown in the fossil record
- 21. The number of years that have passed since the rock formed
- 22. An animal that lives part of its life on land and part in water
- 23. No longer exists and will never again live on earth
- 25. The change in living things over time
- 26. A fossil that widely distributes and represents an organism for a geologically short period of time
- 27. An extremely thin coating of carbon on rock
- 29. A vertebrate that can control its body temperature and feeds milk to its young
Down
- 1. Provides evidence of the activities of ancient organisms
- 2. In undisturbed horizontal rock layers the oldest layer is at the bottom
- 3. Scaly skin and lay eggs that have tough leathery shells
- 4. Fossils in which minerals replace all of an organism
- 7. Scientist that studies fossils
- 14. Units of geological time (subdivision of eras)
- 17. An animal with a backbone
- 18. The time it takes for half of the radioactive atoms to decay
- 20. Many types of living things became extinct at the same time
- 24. A hollow area in sediment in the shape of an organism
- 28. The preserved remains or traces of living things