1. Unit 8 Notes: Populations

2. (1) Population Characteristics
Geographic Distribution: The area/s inhabited by the population.
Density: Number of organisms per unit area within the population’s habitat.
Growth Rate: How fast the population increases or decreases in size over time.

4. (2) Population Growth 3 Factors Affect Growth: Number of births
Number of deaths
Number of organisms entering/leaving

5. (3) Immigration vs Emigration
*This is like when we discussed genetic migration in evolution.
Immigration = Movement of organisms into the population (causes growth).
Emigration = Movement of organisms out of the population (causes decline).

6. (4) Exponential vs Logistic Growth
Exponential  When the individuals in a population reproduce at a constant rate.
Logistic  When the growth slows or stops after a period of exponential growth.
Under ideal conditions with unlimited resources, all populations will grow exponentially.
However challenges like finding a mate, available resources and disease normally prevent this.

8. (5) Carrying Capacity
The largest number of individuals that a given environment can support.
Factors that Determine the Capacity:
Available resources
Disease
Predation & Food Competition
Climate
Human Activity