Chapter 15, 16, 17

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