| A | B |
|---|
| natural selection | process by which organisms best suited to their environmental conditions are most likely to survive and reproduce |
| half-life | the time it takes for one half of the radioactive atoms in a sample to decay |
| radioactive dating | technique for measuring the age of an object by determining the ration of the concentrations of a radio isotope to that of a stable isotope |
| homologous structure | structures that have a common ancestry |
| vestigial structure | structure that has a remnant of an organism's evolutionary past and has no function |
| adaption | process by which a species becomes better suited to its environment |
| balancing selection | situation in which natural selection for an allele is blaanced by selection against it, and the allele remains the same frequency |
| directional selection | situation in which selection for or against an allele in a population is unopposed |
| ecologcal race | a population of a species that differs genetically from other populations of the same species because they have adapted to different environments |
| divergence | accumulation of differences between two or more species or poulations |
| gradualism | hypothesis that evolution occurs at a slow consistent rate |
| punctuated equilibria | hypothesis that evolution occurs at an irregular rate |
