Across
- 2. Mechanism of evolution developed by darwin, based on four ideas excess reproduction, variations, inheritance, and the advantages of specific traits in an environment
- 3. The formation of new species in populations that are geographically isolated from one another.
- 4. process in which individuals with average traits are removed creating two populations with extreme traits
- 6. new feature that had not appeared in common ancestors
- 7. change in the frequency of a trait based on the ability to attract a mate
- 8. allelic frequencies in populations stay the same unless they are affected by a factor that causes change
- 13. mechanisms that operate after fertilization to ensure that the resulting hybrid remains infertile.
- 15. most common form of natural selection in which organisms with extreme expressions of a trait are removed
- 16. shift of a population toward an extreme version of a beneficial trait
- 17. can occur when a small population settles in an area separated from the rest of the population and interbreeds
- 18. selection by humans for breeding of useful traits from the natural variation among different organisms
- 21. study of the distribution of plants and animals on earth
- 23. morphological adaptation in which one species evolves to resemble another species for protection
- 24. more-primitive characteristic that appeared in common ancestors
- 25. A 'leftover' structure. It is non functional and indicates shared ancestry
- 26. hereditary changes in groups of living organisms over time
- 27. A species evolves into a new species without a physical barrier.
- 28. The ability of an individual to survive and reproduce in its specific environment
Down
- 1. theory that evolution occurs with relatively sudden periods of speciation followed by long periods of stability
- 5. same function but different structure that is not inherited from a common ancestor
- 9. Prevents reproduction by making fertilization unlikely through geographical, ecological, behavioral, temporal (time) or other differences.
- 10. similar structure inherited from a common ancestor
- 11. organism's early prebirth stage of development
- 12. diversification of a species into a number of different species over a relatively short time span
- 14. A change in the gene pool of a population due to chance. Changes the frequency of alleles.
- 19. process in which a large population declines in number and rebounds with a different allele frequency.
- 20. theory that evolution occurs in gradual steps over time
- 22. morphological adaptations that allow organisms to blend into their surroundings