1. behavioral isolation - form of reproductive isolation in which two populations have differences in courtship rituals or other types of behavior that prevent them from interbreeding.
2. directional selection - form of natural selection in which the entire curve moves; occurs 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.
3. disruptive selection - form of natural selection in which a single curve splits into two; occurs when individuals at the upper and lower ends of a distribution curve have higher fitness than individuals near the middle.
4. founder effect - change in allele frequencies as a result of the migration of a small subgroup of a population.
5. gene pool - combined genetic information of all the members of a particular population.
6. genetic drift - random change in allele frequencies that occur in small populations.
7. genetic equilibrium - situation in which allele frequencies remain constant.
8. geographic isolation - form of reproductive isolation in which two populations are separated physically by geographic barriers such as rivers, mountains, or stretches of water.
9. Hardy-Weinberg principle - principle that allele frequencies in a population will remain constant unless one or more factors cause the frequencies to change.
10. polygenic trait - trait controlled by two or more genes.
11. relative frequency - number of times an allele occurs in a gene pool compared with the number of times other alleles occur.
12. reproductive isolation - separation of species of populations so that they cannot interbreed and produce offspring.
13. single-gene trait - trait controlled by a single gene that has two alleles.
14. speciation - formation of new species.
15. stabilizing selection - form of natural selection by which the center of the curve remains in its current position; occurs when individuals near the center of a distribution curve have higher fitness than individuals at either end.
16. temporal isolation - form of reproductive isolation in which two populations reproduce at different times.
2. directional selection - form of natural selection in which the entire curve moves; occurs 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.
3. disruptive selection - form of natural selection in which a single curve splits into two; occurs when individuals at the upper and lower ends of a distribution curve have higher fitness than individuals near the middle.
4. founder effect - change in allele frequencies as a result of the migration of a small subgroup of a population.
5. gene pool - combined genetic information of all the members of a particular population.
6. genetic drift - random change in allele frequencies that occur in small populations.
7. genetic equilibrium - situation in which allele frequencies remain constant.
8. geographic isolation - form of reproductive isolation in which two populations are separated physically by geographic barriers such as rivers, mountains, or stretches of water.
9. Hardy-Weinberg principle - principle that allele frequencies in a population will remain constant unless one or more factors cause the frequencies to change.
10. polygenic trait - trait controlled by two or more genes.
11. relative frequency - number of times an allele occurs in a gene pool compared with the number of times other alleles occur.
12. reproductive isolation - separation of species of populations so that they cannot interbreed and produce offspring.
13. single-gene trait - trait controlled by a single gene that has two alleles.
14. speciation - formation of new species.
15. stabilizing selection - form of natural selection by which the center of the curve remains in its current position; occurs when individuals near the center of a distribution curve have higher fitness than individuals at either end.
16. temporal isolation - form of reproductive isolation in which two populations reproduce at different times.