A guild (or ecological guild) is any group of species that exploit the same resources, often in related ways. It does not follow that the species within a guild occupy the same, or even similar, ecological niches. Guilds are defined according to the locations, the attributes, and the activities of their component species; for example, their mode of acquiring nutrients, their mobility, and the zones of their habitat that they occupy or otherwise exploit. The number of guilds occupying an ecosystem is termed its disparity. Members of a guild within a given ecology could be competing for some resources (such as space or light), while cooperating in resisting wind stresses, attracting pollinators, or detecting predators, such as happens among savannah-dwelling antelope and zebra.