Ch. 27 Vocabulary Review

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Across
  1. 2. the source of variation on which asexual organisms depend; an accidental change to an organism’s DNA, potentially resulting in new traits
  2. 6. structures that are no longer functional, but once were (like the appendix)
  3. 7. the pattern of natural selection that favors an extreme phenotype and is indicated by a shifting bell curve
  4. 12. the form of geologic dating that compares strata to those above and below
  5. 14. the slow movement of land masses over time
  6. 17. movement of alleles among populations due to migration
  7. 18. the mechanism by which traits are passed into successive generations
  8. 21. the process by which species become better suited to the environment
  9. 22. the hypothesis that states evolution happens at an irregular rate
  10. 23. change in frequency of alleles due to chance; effects small populations more than large ones
  11. 24. structures that indicate common environment (but not common ancestry); indicative of convergent evolution
  12. 25. the process that produces symbiotic relationships between unrelated organisms
  13. 26. What determines whether a mutation is favorable, unfavorable, or neutral?
Down
  1. 1. the pattern of natural selection that shows speciation is occurring and is indicated by a bell curve with two peaks
  2. 3. the pattern of natural selection that favors average and is indicated by a narrowing bell curve
  3. 4. pairing up of organisms due to genotype or phenotype
  4. 5. evolution of a variety of species from one to take advantage of differences in the environment
  5. 8. structures that indicate common ancestry (but differing environment); indicative of divergent evolution
  6. 9. the number of mass extinctions indicated by the fossil record
  7. 10. evolution along similar lines due to similarity of environment (marsupials and placentals)
  8. 11. genetic drift due to a near-extinction event
  9. 13. evolution of unrelated structures due to similarity of environment (fins of shark, flippers of penquin)
  10. 15. the scientist who believed that acquired traits could be passed on to offspring
  11. 16. the form of absolute dating that compares ratios of unstable isotopes to stable isotopes
  12. 19. the mechanism proposed by Darwin to explain evolution
  13. 20. The island where Darwin began to formulate his theory of natural selection