Across
- 4. effect– a change in allele frequency following a dramatic reduction in the size of a population
- 5. extinction– extinction caused by slow and steady process of natural selection
- 9. effect– change in allele frequencies as a result of the migration of a small subgroup of a population
- 11. structures– body parts that share a common function, but not structure
- 13. to the evolution of at least two species, which occurs in response to changes in other species (have a ecological interdependent relationship)
- 14. selection– when individuals select mates based on heritable traits
- 16. pool–all the genes, including all the different alleles for each gene, that are present in a population at any one time
- 18. selection–form of natural selection in which individuals near the center of a distribution curve have higher fitness than individuals at either end of the curve
- 20. isolation– form of reproductive isolation in which two populations develop differences in courtship rituals or other behaviors that prevent them from breeding
- 21. drift–random change in allele frequency caused by a series of chance occurrences that cause an allele to become more or less common in a population
- 22. radiation (divergent evolution)-- process by which a single species or a small group of species evolves into several different forms that live in different ways
- 25. selection–form of natural selection when individuals at one end of a distribution curve have higher fitness than individuals in the middle or at the other end of the curve
Down
- 1. of a new species
- 2. isolation– form of reproductive isolation in which two or more species reproduces at different times
- 3. equilibrium–pattern of evolution in which long stable periods are interrupted by brief periods of more rapid change
- 6. isolation– separation of a species or population so that they no longer interbreed and evolve into two separate species
- 7. comprising related organisms that share common characteristics and are capable of interbreeding
- 8. evolution of a species by gradual accumulation of small genetic changes over long periods of time
- 10. evolution– process by which unrelated organisms independently evolve similarities when adapting to similar environments
- 12. principle– principle that states that allele frequencies in a population remain constant unless one or more factors cause those frequencies to change
- 15. gene trait–a trait that is controlled by only one gene.
- 17. frequency (relative frequency)-- the number of times that an allele occurs in a gene pool compared with the number of alleles in that pool for the same gene
- 19. isolation– form of reproductive isolation in which two populations are separated by geographic barriers such as rivers, mountains, or bodies of water, leading to the formation of two separate subspecies
- 23. selection– natural selection in which individuals at the upper and lower ends of the curve have higher fitness than individuals near the middle of the curve
- 24. extinction– event during which many species become extinct during a relatively short period of time