Lottery competition
Lottery competition in ecology is a model for how organisms compete. It was first used to describe competition in coral reef fish. Under lottery competition, many offspring compete for a small number of sites. Under lottery competition, one individual is chosen randomly to "win" that site, and the "losers" typically die off. Thus, in an analogy to a lottery or raffle, every individual has an equal chance of winning, and therefore more abundant species are proportionately more likely to win.
Some models generalize this idea by weighting some individuals who are more likely to be chosen. When a population is below carrying capacity, e.g. due to ecological disturbance, then producing twice as many individuals is not identical to producing individuals twice as likely to win; the two specialized groups can coexist in a competition-colonization trade-off.
Lottery competition has been used to in understanding many key ideas in ecology, including the storage effect and neutral theory.