1. Limits to growth
Chapter 5.2

2. Limits to Growth A factor that causes a population to decrease
Limiting Factor
2 types:
Density-dependent Limiting Factor
Density-independent Limiting Factor
A factor that causes a population to decrease
Population size matters
Not effected by population size

3. Density-dependent Limiting Factors
Limiting when the population density reaches a certain level.
Examples:
Competition
Predation
Parasitism
and Disease
- food, space, water, sunlight
- Eating of other organisms
- Cause death

4. Predator-Prey Relationships
As prey #’s increase the predator #’s increase shortly after - More food
Then increase in predators causes decrease in prey populations – More hunters

5. Predator – Lynx
Prey - Hare

6. Density-Independent Limiting Factor
Affect populations regardless of population size.
Examples:
Natural Disasters
Unusual Weather
Seasonal Cycles
Human Activities
-Hurricanes & fires
-Droughts & extreme temps
- Excessive Rain & Seasonal frosts
-Damning Rivers & cutting
forests

8. PREDATOR PREY RELATIONSHIPS

9. POPULATION CYCLES

11. What stops population growth? on Vimeo

12. Human Population Growth
Chapter 5-3

13. History
1. Human population is increasing with time (like many other organisms).
2. About 11,000 years of human existence- population growth was slow.
Reasons:
a. Food was scarce
b. Disease
c. ½ the children survived to adulthood

14. 3. Industrial Revolution changed human growth rate/longevity. a
3. Industrial Revolution changed human growth rate/longevity. a. Food was more plentiful b. Improved sanitation, medicine, nutrition

15. Figure 5-10

16. B. Patterns of Population Growth 1
B. Patterns of Population Growth 1. Demography- study of human populations a. examines characteristics of human populations b. explains how populations change over time 2. Birthrate, death rate, and age structure of a population help predict why some countries have high growth rates while other countries grow more slowly

17. Figure 5-12
Draw on back
of notes
3. Demographic Transition- a dramatic change in birth and death rate a. Birthrates/deathrates- high Deathrates drop/birthrate remains high. Birthrate then drops b. Has occurred in U.S., Europe and Japan- rest of the world still growing

18. 4. Age-Structure Diagram- Population profile a
4. Age-Structure Diagram- Population profile a. Graphs of number of people in different age groups b. Shows percentages of males and females in the populations

19. Figure 5-13

20. C. Future Population Growth 1
C. Future Population Growth 1. Predicts how the world population will grow 2. Must consider a. age-structure b. prevalence of disease 3. Current projections-that by 2050 population may reach 9-12 billion.

22. What’s Behind the Human Population Explosion? •
Three Factors
Fertility
Infant Mortality
Longevity
Animal Domestication and Agriculture
Provided for a few to feed many
Industrial Revolution
Growth of Cities and Infrastructure
Water
Energy
Transportation
Increased Productivity
Nutrition
Sanitation
Medicine

23. How are humans affecting the environment?
Limited Resources –
Land, food, water
Agriculture
Industries
Ecosystem Goods
Renewable
Nonrenewable
Desertification & Deforestation
• Water pollution
• Biological magnification
• Air pollution
• Acid rain
• Habitat Fragmentation
• Introduced Species
 What is the size of YOUR ecological footprint?

25. Human Population Growth