The relationship among births, deaths, and carrying capacity in equilibrium species is that the equilibrium species have a low birth rate and a low death rate and tend to stay near the carrying capacity. The carrying capacity is the population size of the species that the environment can sustain indefinitely, given the food, habitat, water and the other necessities available in the environment. It determines the equilibrium species, together with the death rate and the birth rates of a given species in an ecosystem.