Changing Population Notes

Changing Population Notes
Populations increase by:
Populations decrease by:
1) _______________
3) _______________
2) _______________(organisms entering the area)
4) _______________ (organisms leaving the area)
Population Increase:
Population Stability:
Population Decrease:
Limiting Factors – Anything that prevents populations from ___________ (death rate exceeds birth rate or
emigration exceeds immigration).
Without limiting factors  reproduction > death
Carrying Capacity (k)-
Carry Capacity
Population Crash
Seasonal Fluctuation
Limiting Factors
1) Space – This is the most essential limiting factor. Animals that are territorial (hunting or breeding area) are
often limited by space. Loss of habitat is a loss of space for many organisms.
2) Food (nutrients) and Water (Rainfall for plants) – Lack of these will cause starvation or emigration.
Organisms relying on only one typed of food are most severely affected.
Predator/Prey Graph (hare and lynx)
3) Climate and weather – Temperature changes will affect plant and animal survival. Floods and severe storms
also cause deaths.
4) Cover - Without places to hide organisms are more susceptible to predators and harsh weather.
5) Increase predation – An increase in the number of predators to an area.
6) Disease – Diseases will spread though populations with a high population density.
7) Light – Plants that cannot tolerate shade will die or fail to reproduce.
8) Human Presence - The close proximity of humans may cause certain organisms to emigrate.
Competition among organisms for one of the above factors can cause a decline in populations. Competition
has increased due to exotic species
Exotic Species -