Evolution and Natural Selection

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Across
  1. 7. process by which a new species is formed; occurs when individuals of a population are unable to interbreed or produce fertile offspring
  2. 10. the process by which a species evolves into two or more descendant or different forms; also, the process of tracing two or more species back to a common ancestor
  3. 11. A characteristic that improves an individual's ability to survive and reproduce in a particular environment.
  4. 12. the process in nature by which according to darwins thoery of evolution, only the organisms best adapted to their environment tend to survive and transmit their genetic characteristics in increasing numbers to succeeding generations while those less adapted tend to be eliminated
  5. 14. changes in the genetic material
  6. 15. the relative occurrence (expressed as a percentage) of a gene in a given population
  7. 17. no nucleus
  8. 18. occurs when organisms that formerly interbred are prevented from producing offspring
  9. 19. the independent evolution of similar features in different species that DO NOT share a common ancestor
  10. 20. the total sum of genetic information present in a population at any given moment
Down
  1. 1. has a nucleus
  2. 2. the random change of the occurrance of a particular gene in a population; is it thought to be one cause of speciation when a group of organisms is separated from its parent population
  3. 3. structures having a common evolutionary origin; examples are forelimbs of bats, crocodiles, and humans
  4. 4. when two or more species sharing a common ancestor become more different over time
  5. 5. the process by which two unrelated structures in unrelated organisms evolve to perform similar functions
  6. 6. the production of living organisms from other living organisms
  7. 8. two anatomical structures or behavioral traits within different and unrelated organisms which perform the same functions in each organism but which did not originate from and ancestral structure or trait that the organisms' ancestors had in common. instead, the structures or traits arose separately and then later evolved to perform the same function (or similar functions)
  8. 9. condition in which allelic frequency remains constant over generations; these populations are not evolving
  9. 13. A change or slight difference in condition, amount, or level.
  10. 16. A term that typically describes a species that no longer has any known living individuals