Across
- 2. a change in allele frequency following a dramatic reduction in the size of a population
- 6. formation of a new species
- 9. trait controlled by one gene that has two alleles
- 10. 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. 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
- 15. 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
- 17. classification system in which each species is assigned a two-part scientific name
- 20. in classification, a group of similar genera
- 22. 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
- 23. the evolution of a species by gradual accumulation of small genetic changes over long periods of time
- 27. in classification, a group of closely related families
- 31. group of individuals of the same species that live in the same area
- 34. event during which many species become extinct during a relatively short period of time
- 35. extinction caused by slow and steady process of natural selection
- 36. process by which unrelated organisms independently evolve similarities when adapting to similar environments
- 37. diagram depicting patterns of shared characteristics among species
Down
- 1. 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
- 3. process by which a single species or a small group of species evolves into several different forms that live in different ways
- 4. all the genes, including all the different alleles for each gene, that are present in a population at any one time
- 5. when individuals select mates based on heritable traits
- 7. trait that appears in recent parts of a lineage, but not in its older members
- 8. situation in which allele frequencies in a population remain the same
- 11. group of closely related species; the first part of the scientific name in binomial nomenclature
- 12. in classification, a group of closely related classes
- 13. 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
- 16. process by which two species evolve in response to changes in each other over time
- 18. a group of similar organisms that can breed and produce fertile offspring
- 19. evolutionary branch of a cladogram that includes a single ancestor and all its descendants
- 21. in classification, a group of closely related orders
- 24. pattern of evolution in which long stable periods are interrupted by brief periods of more rapid change
- 25. change in allele frequencies as a result of the migration of a small subgroup of a population
- 26. form of reproductive isolation in which two populations develop differences in courtship rituals or other behaviors that prevent them from breeding
- 28. form of reproductive isolation in which two or more species reproduces at different times
- 29. separation of a species or population so that they no longer interbreed and evolve into two separate species
- 30. study of the diversity of life and the evolutionary relationships between organisms
- 32. group that consists of a single ancestral species and all its descendants and excludes any organisms that are not descended from that common ancestor
- 33. principle principle that states that allele frequencies in a population remain constant unless one or more factors cause those frequencies to change