Biology

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Across
  1. 2. The division of the Earth's history into a series of named units.
  2. 3. Process by which unrelated organisms independently evolve similarities when adapting to similar environments
  3. 5. An evolutionary pattern in which many species evolve from a single ancestral species
  4. 7. English natural scientist who formulated a theory of evolution by natural selection (1809-1882)
  5. 8. Formation of new species
  6. 10. Ability of an organism to survive and reproduce in its environment
  7. 13. A process in which individuals that have certain inherited traits tend to survive and reproduce at higher rates than other individuals because of those traits.
  8. 14. Pattern of evolution in which long stable periods are interrupted by brief periods of more rapid change
  9. 15. Diagram that shows the evolutionary relationships among a group of organisms
  10. 16. principle that all living things were derived from common ancestors
  11. 17. members of each species compete regularly to obtain food, living space, and other necessities of life
  12. 19. A trait that helps an organism survive and reproduce
  13. 20. Structures in different species that are similar because of common ancestry.
Down
  1. 1. scientists who study fossils
  2. 4. mutations
  3. 6. theory that eukaryotic cells formed from a symbiosis among several different prokaryotic organisms
  4. 9. Process by which two species evolve in response to changes in each other
  5. 11. Process by which individuals that are better suited to their environment survive and reproduce most successfully; also called natural selection
  6. 12. Change over time
  7. 18. A term that typically describes a species that no longer has any known living individuals.