Evolution by Natural Selection

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Across
  1. 2. variation in phenotypic traits in which types are grouped into discrete categories with few or no intermediate phenotypes.
  2. 5. the exchange of genes between homologous chromosomes, resulting in a mixture of parental characteristics in offspring.
  3. 7. the intentional breeding of plants or animals1.
  4. 9. the study of genes, genetic variation and heredity in living organisms.
  5. 10. the process whereby organisms better adapted to their environment tend to survive and produce more offspring.
  6. 11. the process by which in successive generations there is a change in the genetic material.
  7. 13. is the process by which organisms develop over time from earlier forms.
  8. 15. systematic change through time.
  9. 16. the theory of the evolution of species by natural selection advanced by Charles Darwin.
  10. 17. variation that has no limit on the value that can occur within a population.
  11. 18. the theory of evolution based on the principle that physical changes in organisms during their lifetime—such as greater development of an organ or a part through increased use—could be transmitted to their offspring.
  12. 19. the study of distribution of species and ecosystems in geographic space and through geological time.
  13. 20. the separation of two populations of the same species or breeding group by a physical barrier.
Down
  1. 1. the process by which one sperm cell randomly fertilizes one egg cell among millions.
  2. 3. are inherited changes that are characteristic of that population over several generations.
  3. 4. the hypothesis that evolutionary development is marked by isolated episodes of rapid speciation between long periods of little or no change.
  4. 6. the formation of new and distinct species in the course of evolution.
  5. 8. a collection of mechanisms, behaviors and physiological processes that prevent the members of two different species that cross or mate from producing offspring, or ensure that any offspring that may be produced are sterile.
  6. 12. a type of cell division that results in four daughter cells each with half the number of chromosomes of the parent cell.
  7. 14. the mating of individuals regardless of any physical, genetic, or social preference.