Vocabulary Unit 7

3. The tropical supercontinent that included North America
4. Change over time
7. The event that began the Paleozoic Era, an explosion of life on Earth
8. A flowering plant
10. An organism that spends some of its life in water and some of its life on land with strong limbs
13. The largest part of geologic history, consists of 90% of the history of the Earth
14. The polar supercontinent during the Paleozoic
15. A catastrophic event that causes most life on Earth to die (has happened 5 times in Earth's history)
17. The Age of Reptiles, ended with the extinction of the dinosaurs
19. The first supercontinent that formed during the Precambrian

1. Petrified remains of the hard parts of organisms
2. Using half-lives of isotopes to determine the age of rocks
5. The Age of Fish and Amphibians, ended with the largest mass extinction in Earth's history
6. Evidence that shows when oxygen formed on Earth
9. The final supercontinent that formed and broke up during the Mesozoic Era
11. The current geologic time period, also known as the Age of Mammals
12. An egg with many layers used to feed the growing organism inside
16. Large-scale and long-term differences in Earth's temperature and precipitation
18. An organism with hard-shelled eggs, strong limbs and teeth, scales, and claws