Unified neutral theory of biodiversity
The unified neutral theory of biodiversity and biogeography is a theory and the title of a monograph by ecologist Stephen P. Hubbell. It aims to explain the diversity and relative abundance of species in ecological communities. Like other neutral theories of ecology, Hubbell assumes that the differences between members of an ecological community of trophically similar species are "neutral", or irrelevant to their success. This implies that niche differences do not influence abundance and the abundance of each species follows a random walk. The theory has sparked controversy, and some authors consider it a more complex version of other null models that fit the data better.
Unified neutral theory of biodiversity
In ecology, a niche is the match of a species to a specific environmental condition. It describes how an organism or population responds to the distribution of resources and competitors and how it in turn alters those same factors. "The type and number of variables comprising the dimensions of an environmental niche vary from one species to another [and] the relative importance of particular environmental variables for a species may vary according to the geographic and biotic contexts".
The flightless dung beetle occupies an ecological niche: exploiting animal droppings as a food source.
The Grinnellian niche can be described as the "needs" niche, or an area that meets the environmental requirements for an organism's survival. Most succulents are native in dry, arid regions like deserts and require large quantities of sun exposure.
Beaver dam in Hesse, Germany. By exploiting the resource of available wood, beavers are affecting biotic conditions for other species that live within their habitat.
The shape of the bill of this purple-throated carib is complementary to the shape of the flower and coevolved with it, enabling it to exploit the nectar as a resource.
