Ecosystems Limiting Factors

Let’s suppose…. We have two mice…: and they produce the standard 56 “pups” (baby mice) each year. and each of these mice goes on to have 56 babies each year….

Soon….. We’d be over-run with mice on the planet!! Why doesn’t this occur?

Limiting Factors A limiting factor is an abiotic or biotic factor that restricts the number of individuals in a population.

Limiting Factors Limiting factors can include: Competitors Disease and parasites Natural Disasters Available habitat Predators

Competitors & Competition a) Competition results when organisms struggle to survive in a habitat with limited resources b) For examples: birds of prey: Both live in forests on the edge of fields Both eat Mice and other rodents Both nest in Trees Because both live in the same habitat, use the same resources, they compete with each other. Red-Tailed Hawk Barred Owl

Disease and Parasites Diseases and parasites can be dependent on population size and habitat Larger population = more parasites and disease, which also limits how big the population gets

Natural Disasters Natural Disasters can destroy habitats, and food sources. These include: Storms Droughts Flooding Heat/cold Fires These disasters destroy habitats, food sources, and even the kill the populations themselves.

Available Habitat Human activities play a large role Development (homes, buildings, parking lots), damming rivers, clear cutting forests, hunting. Parts of the habitat can also be limiting: amount of food(prey), available nesting sites

Predators Predator-prey relationships can be a delicate balance between the two populations.

Predators As the prey population increases, the predator population increases. As the prey population decreases, then so does the predator population.

Example: Lynx and Hare:

What is Carrying Capacity? Because of these limiting factors, each ecosystem has a limited capacity for growth connected to its carrying capacity.

What is Carrying Capacity? Carrying capacity is the maximum number of individuals of a species that an ecosystem can support.

Limiting Factors In nature, populations of organisms rarely grow uncontrolled. Each ecosystem has a carrying capacity (or number of organisms it can sustain/support). Remember, limiting factors are biotic and abiotic factors that prevent the continuous growth of a population. Because of limiting factors, the number of organisms in a population is often well below carrying capacity.