Across
- 4. - process by which unrelated organisms independently evolve similarities when adapting to similar environments
- 5. - situation in which allele frequencies in a population remain the same
- 7. - 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
- 11. - process by which two species evolve in response to changes in each other over time
- 13. - a change in allele frequency following a dramatic reduction in the size of a population
- 14. - event during which many species become extinct during a relatively short period of time
- 16. - 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
- 21. - 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
- 22. - pattern of evolution in which long stable periods are interrupted by brief periods of more rapid change
- 23. - form of reproductive isolation in which two or more species reproduces at different times
- 25. - process by which a single species or a small group of species evolves into several different forms that live in different ways
- 26. - changes in anatomy, phylogeny, ecology, and behavior that can take place in clades larger than a single species
Down
- 1. - form of reproductive isolation in which two populations develop differences in courtship rituals or other behaviors that prevent them from breeding
- 2. - group of individuals of the same species that live in the same area
- 3. - when individuals select mates based on heritable traits
- 6. - extinction caused by slow and steady process of natural selection
- 8. - 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
- 9. - separation of a species or population so that they no longer interbreed and evolve into two separate species
- 10. - 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
- 12. - formation of a new species
- 15. - all the genes, including all the different alleles for each gene, that are present in a population at any one time
- 17. - change in allele frequencies as a result of the migration of a small subgroup of a population
- 18. - principle that states that allele frequencies in a population remain constant unless one or more factors cause those frequencies to change
- 19. -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
- 20. - the evolution of a species by gradual accumulation of small genetic changes over long periods of time
- 24. - a group of similar organisms that can breed and produce fertile offspring