Natural Selection and Speciation

Edit Answers
123456789101112131415161718192021
Across
  1. 1. genetic differences among individuals in a population
  2. 3. heritable trait or behavior in an organism that aids in its survival and reproduction in its present environment
  3. 6. model that shows how species diverge gradually over time in small steps
  4. 9. formation of a new species
  5. 11. group of populations that interbreed and produce fertile offspring
  6. 13. condition of a cell having an extra chromosome or missing a chromosome for its species
  7. 14. offspring of two closely related individuals, not of the same species
  8. 16. prezygotic barrier occurring when closely related individuals of different species mate, but differences in their gamete cells (eggs and sperm) prevent fertilization from taking place
  9. 18. differences in breeding schedules that can act as a form of prezygotic barrier leading to reproductive isolation variation genetic differences among individuals in a population
  10. 20. area where two closely related species continue to interact and reproduce, forming hybrids
  11. 21. reproductive isolation resulting when species' populations move or are moved to a new habitat, taking up residence in a place that no longer overlaps with the same species' other populations
Down
  1. 2. situation that occurs when a species is reproductively independent from other species; behavior, location, or reproductive barriers may cause this to happen
  2. 4. process by which groups of organisms independently evolve to similar forms
  3. 5. speciation that occurs via geographic separation
  4. 7. allopatric speciation that occurs when something in the environment separates organisms of the same species into separate groups
  5. 8. type of reproductive isolation that occurs when a specific behavior or lack of one prevents reproduction from taking place
  6. 10. reproduction of individuals with favorable genetic traits that survive environmental change because of those traits, leading to evolutionary change
  7. 12. process by which groups of organisms evolve in diverse directions from a common point
  8. 15. model for rapid speciation that can occur when an event causes a small portion of a population to be cut off from the rest of the population
  9. 17. reproductive isolation mechanism that occurs after zygote formation
  10. 19. reproductive isolation mechanism that occurs before zygote formation