1. (Write the stuff in GREEN)
How Populations Grow
(Write the stuff in GREEN)

2. FOUR MAIN CHARACTERISTICS
Populations
FOUR MAIN CHARACTERISTICS
Geographic Distribution
The range or area inhabited by a population
Density
Number of individuals per unit area
Varies from organism to organism and from biome to biome
Growth Rate
Age structure *

3. Let's Try Something!
Population Density = Number of Individuals ÷ Unit Area
Unit Area of Biology Room = ~72 m2
What is the population density in the biology room?
What if our class moved to the gym (about 638 m2)…would the population density be the same? If not, what would it be?

4. Population Growth Three factors affect population size
Number of births
Number of deaths
Number of individuals that leave or enter
Immigration-movement of individuals into
Emigration-movement of individuals out

5. Exponential Growth
If a population has abundant space and food, AND is protected from predators and disease, then that population will multiply and the population size will increase
Why isn’t the world overrun with bunnies or elephants?
Exponential growth: occurs when the individuals in a population reproduce at a constant rate
Under ideal conditions with unlimited resources, a population will grow exponentially

6. Logistic Growth
As resources become less available, the growth of a population slows or stops
Logistic growth occurs when a population’s growth slows or stops following a period of exponential growth
Carrying capacity: largest number of individuals an ecosystem can support

7. Growth Curves