1. Ecosystems
Limiting Factors

2. 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….

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

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

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

6. 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

7. 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

8. 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.

9. 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

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

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

12. Example: Lynx and Hare:

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

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

15. 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.