1. Factors that Limit Population

2. Population Size Can change over time
As a population grows it puts more demands on the ecosystem’s resources.
Ex: large population of lions will need more food than a small population
If there’s not enough food, some will die.
Size of the population is thus limited by available food.

3. Limiting Factors
Environmental factors that limit the size of a population
Available water, oxygen, food, and sunlight.

4. Density-Dependent Factors
Limit growth of a population
Occurs when population density reaches a certain area
Predation and competition
Predator/prey populations  if predator pop. Is too large, there won’t be enough prey so some will die off.
As pred. pop. decreases, prey pop. increases

5. Density-Independent Factors
Limit growth of pop. Regardless of size
Ex: extreme temperatures, tidal wave, volcano, flooding, etc.

6. Carrying Capacity
The largest population an environment can support.

7. Cycling Matter
Photosynthesis and cellular respiration are a continuous cycle called the carbon cycle.
Nutrients flow between organisms and their environment.

8. Plant and Animal Effects
Plants remove CO2 from the atmosphere to make food and release O2 into the atmosphere
Animals remove O2 from the atmosphere and release CO2

9. Decomposer Effects Break down dead/decaying matter
Return energy and nutrients to the ecosystem
Ex: fungi and bacteria

10. Human Impact on Environment
Humans place stress on the environment by constantly changing resources.
Human population: Stayed stable for many years, then grew significantly.

11. Effects of Population Running out of resources and energy.
Increase in pollution
In water can cause algal blooms which use up all the oxygen.
Urbanization: clearing of land causes other organisms to relocate.
Deforestation: clearing of trees

12. Resource Depletion
Trees being removed are renewable resources but if they are not being replaced as quickly as they are cleared resource depletion.

13. Climate Change
Global warming  increased burning of fossil fuels.