Unit 4 Part B

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Across
  1. 6. structure - feature that a species inherited from an ancestor but that is now less elaborate and functional than in the ancestor.
  2. 8. - modification of an organism or its parts that makes it more fit for existence under the conditions of its environment
  3. 11. - the amount of offspring an animal has and how old they become
  4. 12. - the remains or impression of a prehistoric organism preserved in petrified form or as a mold or cast in rock.
  5. 15. - the formation of new and distinct species in the course of evolution
  6. 16. - the fact or process of a species, family, or other group of animals or plants becoming extinct
  7. 17. selection - the identification by humans of desirable traits in plants and animals, and the steps taken to enhance and perpetuate those traits in future generations
  8. 18. divergence - the process in which two or more populations of an ancestral species accumulate independent genetic changes (mutations) through time
  9. 19. isolation - happens when two or more species reproduce at different times
  10. 20. - sequences of DNA
  11. 21. selection -a mechanism of evolution where some characteristics are more favored naturally.
Down
  1. 1. isolation - The physical separation of members of a population
  2. 2. of the fittest - organisms best adjusted to their environment are the most successful in surviving and reproducing
  3. 3. - the process by which species adapt over time in response to their changing environment
  4. 4. - the action or process of mutating
  5. 5. isolation - The separation of groups of organisms as a result of changes in their ecology or in the environment in which they live
  6. 7. drift - variation in the relative frequency of different genotypes in a small population, owing to the chance disappearance of particular genes as individuals die or do not reproduce.
  7. 9. isolation - the reduction of gene flow between populations or species due to differences in courtship signals and preferences
  8. 10. structure - similar physical features in organisms that share a common ancestor, but the features serve completely different functions
  9. 13. structure - features of different species that are similar in function but not necessarily in structure and which do not derive from a common ancestral feature
  10. 14. isolation - a physical incompatibility between reproductive organs of two organisms