1. Chapter 5
Populations

2. Section 5-1, Population Ecology
What types of factors can affect the size of this population of otters?

3. Characteristics of a Population
Geographic distribution- range, area inhabited by a population
Density- number of organisms in a given area
Growth rate- increase or decrease in the number of organisms in a population over time

4. Factors that Affect Population Growth
Number of births
Number of deaths
Number of individuals that enter (immigration) or leave (emigration) the population
A population can grow when its birthrate is greater than its death rate.

5. Exponential Growth Under ideal conditions there would be…
Unlimited Resources
No limit on population size
A population will grow exponentially if there are no limiting factors and the individuals in the population reproduce at a constant rate.
In nature, one population cannot grow exponentially forever.

6. Logistic Growth
When a population’s growth slows down or stops, following a period of exponential growth.
S-shaped curve

7. Carrying Capacity
The largest number of individuals in a population that an environment can support.
When a population reaches carrying capacity, growth rate = 0.

8. Logistic Growth Model
Carrying Capacity