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| What is a gene pool? | the combined genetic information of all the members of a particular population |
| What is relative frequency? | the number of times that an allele occurs in a gene pool compared with the number of times other alleles occur |
| Two main sources of genetic variation are... | mutation and genetic shuffling that results from sexual reproduction |
| The number or phenotypes produces for a given trait depends on... | how many genes control that trait |
| What is a single gene trait? | controlled by a single gene that has two alleles, as a result variation leads to only two distinct phenotypes |
| What are polygenic traits? | traits that are contolled by two or more genes |
| Natural selection on single gene traits can lead to... | changes in allele frequencies and thus to evolution |
| Natural selection can affect the distribution of phenotypes in any of three ways... | directional selection, stabilizing selection or disruptive selection |
| What is directional selection? | occurs when individuals at one end of the curve have higher fitness than individuals in the middle or at the other end |
| What is stabilizing selection? | takes place when individuals near the center of a curve have higher fitness than individuals at either end |
| What is disruptive selection? | When individuals at the upper and lower ends of the curve have higher fitness than individuals near the middle |
| What is genetic drift? | random change in allele frequencies that occurs in small populations |
| What is the founder effect? | a situation in which allele frequencies change as a result of the migration of a small subgroup of a population |
| The Hardy-Weinberg principle states... | that allele frequencies in a population will remain sonstant unless one or more factors cause those freuqencies to change |
| What is genetic equilibrium? | the situation in which allele frequencies remain constant |
| What are the five conditions that are required to maintain genetic equilibrium from generation to generation? | random mating, population must be very large, no movement into or out of the population, no mutations, no natural selection |
| What is speciation? | the formation of a new species |
| Wht is reproductive isolation? | when the members of two populaitons cannot interbreed and produce fertile offspring |
| What is behavioral isolation? | when two populations are capable of interbreeding but have differences in courtship rituals or other types of behavior |
| What is geographic isolation? | two populations are separated by geographic barriers such as rivers, mountains, or bodies of water |
