1. IV. Properties of Populations

2. 1. Birth Rate vs. Death Rate
A. Population Growth
1. Birth Rate vs. Death Rate
2. Immigration (individuals move into a population)
vs.
Emigration (individuals move out of a population)

3. Exponential Growth
Logistical Growth

4. B. Carrying Capacity:
The largest number of individuals (in a specific population) that an ecosystem can support
Carrying Capacity
Determined by limiting factors

5. 1. Density Independent Factors:
C. Limiting Factors:
Factors that cause population growth to stop or decrease
(keep a population’s size in check)
1. Density Independent Factors:
Affect populations regardless of their size/density
a. Weather (hurricanes, tornadoes, temperature, etc.)
b. Natural Disasters (earthquakes, tsunamis, floods, etc.)
c. Seasonal Cycles (Some insects die in the winter)
d. Human Activities (deforestation, pollution, etc.)

6. 2. Density Dependent Factors :
Take affect when population is large and dense
a. Resources (food, water, sunlight, living space, etc.)
When individuals or species share the same niche (role in ecosystem), they compete for limited resources.
Ex: Finches compete for seeds
Ex: Owls and snakes compete for mice

7. b. Parasitism and Disease
Spread easily when the population is dense
c. Predation
PREDATOR/PREY RELATIONSHIPS