UNIT 8 VOCABULARY

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Across
  1. 4. A phrase that describes natural selection. Fit as opposed to unfit
  2. 6. The evolution of a new species
  3. 8. Natural selection that favors the average individuals in a population
  4. 10. Human select useful variations or traits they desire in organisms
  5. 11. The change in allelic frequencies caused by a chance event
  6. 12. When members of a population can no longer mate and produce fertile offspring
  7. 15. When species that were once similar to an ancestral species diverge
  8. 17. Natural selection that favors either extreme of a traits variation
  9. 18. A population in which the frequency of alleles remains the same
  10. 19. Gradual change in a species through adaptations over time.
  11. 20. Physical evidence of an organism that lived long ago that scientist use to study the past.
  12. 22. The traits that help an organism survive in a particular environment are “selected’ in natural selection
Down
  1. 1. A structure in present-day organisms that no longer serve a purpose
  2. 2. Natural selection that favors one of the extreme variations of a trait
  3. 3. Provide evidence of evolution from a common ancestor, arm of human and wing of a bat are examples.
  4. 5. Speciation occurs rather quickly and in rapid bursts
  5. 7. All of the alleles of a population’s genes
  6. 9. When a physical barrier separates a population
  7. 13. Structures that do not have a common evolutionary origin but are similar in function.
  8. 14. When distantly related organisms evolve similar traits
  9. 16. The idea that species originate through a gradual change in adaptations
  10. 21. Well supported explanation of phenomena that has occurred in the natural world