1. Population Ecology
ORTIS Project: Lesson 11

2. Follow-Up to Lesson 10
What factors can limit a population?

3. Limiting Factors for Populations
Limiting Factors can affect the number of organisms (i.e. population of people, animal, or plants) in a region/country

4. Limiting Factors for Populations
Limiting factors can be:
Density Dependent or
Density Independent
*Density = number of individuals per unit of area
(Ex. = 65 people per square mile)

5. Density Dependent Limiting Factors
Density dependent factors (factors affected by the number of people/animals /plants living in the particular area.)
Amount of food available
Living space
Disease
Competition
Predation
In other words, these factors are directly related to how many individuals there are.

6. Density Independent Limiting Factors
Density independent factors (these have nothing to do with the number of people/ animals/plants living in a given area)
Weather
Seasonal cycles
Natural disasters
Human activities
The number of individuals is irrelevant to how these factors will affect the population.

7. Specific examples of Density Independent factors
Natural disasters
Drought
Fire
Volcanic eruption
Human activities
Housing development
Road building
Farming

8. 7,000,000,000 7 Billion People What does this number mean to you?
In M&M’s?
You would have to eat 10 every second of every minute of every day for 22 years!!!
That is 13,117,504.6 pounds or 276,744 school buses

9. 7 Billion People: National Geographic
Video
7 Billion People: National Geographic

10. Question Generation
Open discussion about video

11. Human Population Growth
In groups of 2-3 make conclusions about the human population graph.

12. Human Population Growth
A.D.
2000
1000 1
B.C.
3000
4000
5000
6000
7000
1+ million
years 8 7 6 5 2 4 3
Old
Stone
Age
New Stone Age
Bronze
Iron
Middle
Ages
Modern
Black Death —
The Plague 9 10 11 12
1800
1900
1950
1975
2100
Future
Billions

13. Why? The Germ Theory Food Production Food Distribution Sanitation
Antibiotics
Food Production
Food Distribution

14. Germ Theory
We began to understand that diseases were caused by germs (microbes).
This led to new sterile techniques in the operating room.
More sterile techniques when handling food and water.
A better understanding of sanitation.
A better understanding of disease transmission.
A better understanding of disease treatments and ultimately antibiotics.
Bottom line is a decreased deathrate leads to an increase in population size.

15. Food Production and Food Distribution
Advances in the preservation of foods.
Advances in the transportation and distribution of foods.
Advances in farming methods using new technologies to decrease labor.