1. Notes: Population Growth
Monday
Notes: Population Growth

2. (1) Population Change/Development
Stage 1 = Growth
Abundance of resources
Population size increases
More births than deaths
Stage 2 = Stability
Resource quantity constant
Population size constant
# of births and deaths cancel out
Stage 3 = Decline
Decrease in resources
Population size decreases
More deaths than births

3. Growth
Stability
Decline
# of Individuals
Carrying Capacity
Time

4. (2) Population Growth
Population Growth: Overall Increase in the number of organisms w/in a population.
Impacted By:
# of Births
# of Deaths
# of organisms immigrating IN
# of organisms emigrating OUT

5. (3) Exponential Growth
Exponential Growth: The consistent growth/increase of a population at the same proportion, over time.
Curved Line Graph
Under Ideal Conditions, populations will grow Exponentially.
Why Use Then?!?
Good for Predictions

6. Exponential Curve

7. (4) Logistic Growth
Logistic Growth: The consistent growth/increase of a population for a period of time, until reaching carrying capacity and leveling off.
S-Curved Line Graph

9. (5) Carrying Capacity
Carrying Capacity: Maximum population size an ecosystem can support.
Needed:
Enough biotic and abiotic resources
Correct types of biotic and abiotic resources
Enough deaths to balance out births

11. (6) Limiting Factors
Limiting Factors: Components of an ecosystem that drastically alter a population’s size.
Types:
Density Dependent = Based on # of Organisms
Parasitism , Disease
Predation
Density Independent = NOT Related to # of Organisms
Weather
Natural Disasters
Human Activity

13. (7) Human Population Current Size: 1950 = 2.5 billion people
Growth Rate:
More births than deaths
Only drop occurred during Middle Ages with “Black Death”
Wars, Aids, “Colds” = Not Enough Deaths!
1880’s = Sanitation Laws first initiated
Late 1990’s = Widespread medical use of technology and antibiotics
Between 1880 and 1990 the death rate dropped from 1.7% to 0.7%!

14. According to the graph, what is the approximate size of our current population?
What stage of development are we in right now?
What is allowing us to be in this stage?
What do you think will happen to our population after that hump? Why?
Does this graph show linear or exponential growth? Why is exponential growth more concerning than linear?
According to the graph, What will be the our approximate population size in 2075?

16. (8) Demographic Transition
Definition: The changes in birth and death rates, over time, ultimately stopping a large population’s accelerated growth.
Developed Nations: (like United States)
Have not yet completed transition
Money allows nations to continue growth
Poor Nations: (South America, Africa)
Have completed transition
Lack of money  carrying capacity