1. Population Growth Patterns

2. Population Size Factors
Population sizes change based on resources
Increase
Immigration
Births
Decrease
Emigration
Deaths

3. Exponential Growth Growth rates determined by abundant resources
Dramatic population increases over time
J-shaped curve

4. Logistic Growth Most populations faced with limited resources
Factors: Disease, food, predators, climate, space, mates
Three stages
1) Slow growth
2) Exponential growth
3) Carrying Capacity: greatest number of individuals that a population can sustain
S-shaped curve

5. Population Crash Defined: Dramatic decline in the size of a population
Usually over a short time period
Causes: Environment changes, drop in resources

6. Limiting Factors
Density Dependent: factors that are affected by the individuals in a given area
Competition
Predation
Parasitism
Disease
Density Independent: environmental factors that limit populations
Climate/weather
Natural disasters
Human activity

7. Density Dependent
Top graph: Two species of Paramecia were grown in two separate containers. Both populations thrived.
Bottom graph: Due to competition, Paramecium caudatum crashed when grown in the presence of Paramecium aurelia

8. Density Independent
This graph shows the decline in the population of one of Darwin's finches on Daphne Major, a tiny (100-acre) member of the Galapagos Islands. The decline (from 1400 to 200 individuals) occurred because of a severe drought that reduced the quantity of seeds on which this species feeds. The drought ended in 1978, but even with ample food once again available the finch population recovered only slowly.