Science

allele | One of two or more molecular forms of a gene that arise by mutation and code. |
allele frequency | the relative abundances of each kind of allele among all the individuals of a population.|
antibiotic | Metabolic product of soil microbes that kills bacterial competitors for nutrients. |
balanced polymorphism | Form of selection in which two or more alleles for a trait are beingmaintained in a population over time. |
biogeography | Scientific study of the world distribution of species. |
bottleneck | Severe reduction in the size of a population. |
catastrophism | Ideathat abrupt changes in the geologic or fossil record were divinely invoked. |
comparative morphology | Scientific study of comparable body parts of adults or embryonic stages of major lineages. |directional selection | Mode of natural selection by which allele frequencies underlying a range of phenotypic variation shift in a consistent direction. |
disruptive selection | Mode of naturalselection by which the different forms of a trait at both ends of the range of variation are favored and intermediate forms are selected against. |
evolution | Genetic change in a line of descent. |fitness | Increase in adaptation to environment. |
fixation | Loss of all but one kind of allele at a gene locus for all individuals in a population. |
fossil | physical evidence of an organismthat lived in the distant past. |
founder effect | a few individuals that establish a new population have allele frequencies that differ from those of the original population. |
gene flow |Microevolutionary process; alleles enter and leave a population as an outcome of immigration and emigration |
gene pool | All genotypes in a population. |
genetic drift | Change in allele frequencies overthe generations due to chance alone. |
genetic equilibrium | a state in which a population is not evolving. |
Hardy-Weinberg rule | Allele frequencies stay the same over the generations when...