Across
- 2. Change over time
- 5. period of time
- 8. no longer existing
- 10. isolation between populations due to differences in courtship or mating behavior
- 11. trait controlled by two or more genes
- 13. situation in which allele frequencies remain constant
- 16. isolation between populations due to physical barriers
- 17. microscopic fossils
- 18. Process by which two species evolve in response to changes in each other
- 20. Formation of new species
Down
- 1. When two species breed at different times of day, season, or years
- 3. scientists who study fossils
- 4. A trait that helps an organism survive and reproduce
- 6. A change in the gene pool of a population due to chance
- 7. A hypothesis that has been tested with a significant amount of data
- 9. separation of a species or population so that they no longer interbreed and evolve into two separate species
- 12. A row on the periodic table
- 14. Evolutionary change above the species level
- 15. A trace of an ancient organism that has been preserved in rock
- 19. ability to survive and reproduce