Across
- 7. genetic drift that results from an event that drastically reduced the size of a population
- 8. isolation due to physical barriers
- 9. pathway of natural selection in which intermediate phenotypes are selected over phenotypes at both extremes
- 10. process in which 2 or more species evolves in response to changes in each other
- 12. physical region of alleles from one population to another
- 13. the gradual development of something, especially from a simple to a more complex form
- 15. isolation between populations due to difference in mating behavior
- 16. pathway of natural selection in which 2 opposite, but equally uncommon, phenotypes are selected over the most common phenotype
- 18. final stage in speciation, in which members of isolation population are either no longer able to mate
- 19. theory that states that speciation occurs suddenly and rapidly followed by long periods of little evolution change
- 20. observable change in the allele freqencies of a population over a few generations
- 21. evolution of 2 or more species from 1 ancestral species
- 22. elimination of a species from Earth
- 23. collection of alleles found in all of the individuals of a population
- 24. evolution of one or more closely related species
- 25. isolation between populations due to barriers related to time, such as difference in mating periods or difference in the time of day that individuals are most active
Down
- 1. distribution in population in which allele frequency is highest near mean range value and decrease progressively toward each extreme end
- 2. genetic drift that occurs after a small number of individuals colonize a new area
- 3. process by which one species evolves and gives rise to many descendant species that occupies different ecological niches
- 4. change in allele frequencies due to chance alone, occuring most commonly in small populations
- 5. pathway of natural selection in which one uncommon phenotype is selected over a more common phenotype
- 6. condition in which a population's allele frequencies for a given trait don't change from generation to generation
- 11. proportion of one allele compared with all the alleles for that trait
- 14. selection in which certain traits enhance mating success
- 17. evolution toward similar characteristics in unrelated species, resulting from adaptions to similar environmental conditions