Across
- 2. all living things derive from common ancestor
- 6. competition
- 11. inner germ layer
- 15. outer germ layer
- 16. diagram shows evolutionary relationships among group of organisms
- 17. ability to survive and reproduce in environment
- 19. a scientist who studies fossils
- 20. small group evolves
- 21. long stable time interrupted by rapid change
Down
- 1. mutations
- 3. He studied evolution and finches
- 4. two species evolve in response to each other
- 5. middle germ layer
- 7. when a species dies out
- 8. also called natural selection
- 9. a trait that increases fitness
- 10. selection also called survival of the fittest
- 12. formation of new species
- 13. structure inherited but lost purpose or use.
- 14. Earth's history divided into time frame.
- 18. change over time