The ecological niche is determined by the different environmental factors that allow a species to survive and ensure its reproduction. A distinction is made between biotic factors and abiotic factors. Biotic factors may be a type of food source or the size of the food, abiotic factors are e.g. Temperature, light intensity, humidity or even the salinity of the drinking water. The ecological niche is therefore less the habitat in which a species lives, but rather the functional relationship in which this species is part of the ecosystem.
The formation of different ecological niches is called Einnischung. This leads to the fact that several species share the same habitat and can exist side by side, ie a coexistence is basically possible. If several species in the same ecosystem had similar claims, then an enormous competition would be generated which would ultimately displace more and more species (competition exclusion principle). By exploiting special environmental offers through a species, this eludes the inter-species competition. The Einnischung therefore leads to the different use of the same habitat by different species and receives them.
But also species that live in geographically separate areas can form similar ecological niches and therefore often have similarities in shape and lifestyle, although they are not related to compared other species. So they form a convergence.