Evolution Crossword Study Guide

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Across
  1. 4. way to determine a fossil's age through its placement in rock formations
  2. 8. when all the organisms in a species die; there are no more of that species alive
  3. 9. the time it takes for half the isotopes in a radioisotope to decay
  4. 10. average and one extreme are more fit to survive
  5. 11. selection survival of the fittest
  6. 12. when a species conceals itself within its environment
  7. 13. the organism's ability to survive and reproduce in an environment
  8. 14. when a population becomes a distinct species
Down
  1. 1. structure that appears in multiple different species
  2. 2. change over time
  3. 3. both extremes are more fit to survive than the average
  4. 5. remains of ancient organisms
  5. 6. all the possible genes in a population
  6. 7. features a species gains that helps it survive in its environment