disruptive selection Selection that changes the frequency of alleles in a divergent manner, leading to the fixation of alternative alleles in members of the population. The result after several generations of selection should be two divergent phenotypic extremes within the population; this process has been thought to provide a possible mechanism for sympatric speciation (see SYMPATRIC EVOLUTION). Compare DIRECTIONAL SELECTION; STABLILIZING SELECTION.

disruptive selection A selection that changes the frequency of alleles in a divergent manner, leading to the fixation of alternative alleles in members of the population. The result after several generations of selection should be two divergent phenotypic extremes within the population. This may be achieved, for example, by selecting seeds from the longest and shortest ears of corn in a population over a number of generations. Compare DIRECTIONAL SELECTION.

disruptive selection A selection that changes the frequency of alleles in a divergent manner, leading to the fixation of alternative alleles in members of the population. The result after several generations of selection should be two divergent phenotypic extremes within the population. This may be achieved, for example, by selecting seeds from the longest and shortest ears of corn in a population over a number of generations. Compare directional selection and stabilizing selection.

disruptive selection Natural selection that favours the extremes of a phenotype in a population. It often operates when an environmental factor shows distinct variations, for example high temperatures in summer and low temperatures in winter, with no intermediate forms. In this case the population will be variously adapted to withstand both high and low temperatures.