3.4: Carrying Capacity

A population is a group of organisms of the same species that live in a particular geographic area. Each population needs specific resources due to size, reproductive strategies, and survivorship curves. However, there is a limit to the number of individuals that an ecosystem can support.  

Ecosystem Limitations

If ecosystems had an infinite amount of resources, populations would grow exponentially. Since resources are, in fact, finite, carrying capacity (K) is the maximum population size of a species that can be sustained, given the food, habitat, water, sunlight, and other necessities available in the environment. 

Once a population exceeds carrying capacity, a population overshoot occurs. Population overshoot can lead to a range of negative consequences, such as resource depletion, environmental degradation, and increased competition for resources. In some cases, population overshoot can lead to a population crash, where the population size decreases rapidly as individuals are unable to find the resources they need to survive. This crash is also referred to as a die-off. 

Die-offs are attributable to combinations of a lack of available resources, famine, disease, and competition.