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