1. Breakout Questions: In this sign, what does “Maximum Capacity” mean?
What would happen if that capacity was exceeded?

2. Population Ecology Notes
Demography is the scientific study of human populations.
Population: a group of organisms of one species that interbreed and live in the same place at the same time

3. Population Ecology Notes
Limiting factor: any biotic or abiotic factor that restricts the existence, numbers, or reproduction of an organism

4. 4 factors which affect population growth:
Natality = number of births
Mortality = number of deaths
Immigration = number moving into a population
Emigration = number moving out of a population

5. Patterns of population growth
1) Slow reproduction - reproduce a few young, live in stable environments, usually large in size and maintain sizes at carrying capacity. Ex: elephants, humans
2) Rapid reproduction - produce many offspring in short periods of time, live in unpredictable environments that change rapidly, usually small in size and have short life spans. Ex: mosquitoes

6. Population Curves J-curve (also called the Exponential Curve)
Initial increase in the number of organisms is slow, and then the population begins to increase rapidly
Exponential growth occurs when the number of organism rises at an ever-increasing rate

7. S-curve (also called the Logistic Curve)
Population initially increases and then levels off
Carrying capacity = the number of organisms that an environment can support over an indefinite period of time

8. Carrying Capacity
Largest population an environment can support at any time
Population can increase beyond this number but cannot stay elevated

9. Carrying Capacity
Estimated by average population sizes or by observing population diebacks after a certain size has been exceeded

10. 2 kinds of limiting factors
Density-dependent factors:
includes disease, competition, and parasites which have an increasing effect as the population increases
Density-independent factors:
affects all populations regardless of their density such as temperature, storms, floods, or droughts

11. World Population 1800s brought exponential growth food production
hygiene
medicine

12. Age-Structure Diagram
Population grouped by age/gender
More young than old - high growth rate
Even distribution of ages - slow or no growth

13. Age-Structure Diagram Analysis1 2 3
Are there more males or females?
Which country would have low immigration?
Which country has a high life expectancy?
Which country has low fertility rate?
What is happening in the third country?
More females world-wide
Country 1 – developing
Country 3 – developed
Country 3
Country 2 – transitional

14. Demographic Transition
Change from high birth and death rates to low birth and death rates
Industrial development may affect population growth rate

15. Stages of the Transition
First stage: pre-industrial society
birth rate and death rate are high
Second stage: population explosion
Death rates decline; birth rates stay high

16. Stages of the Transition
Third stage: birth rate decreases
Population size stabilizes (much larger than before)
Fourth stage: birth rate drops below replacement level
Population decreases
Takes 1-3 generations for demographic transition to occur

17. Flow Chart
Create a flow chart to summarize the stages of demographic transition
Age Structure

18. Development and Population
Some countries may never become developed, due to population growth rates
incentives to reduce fertility rates

19. Slowing Growth Population growth is slowing this century
World population growth will stabilize by 2050
at 9 billion
More Is Less III

20. What Did You Learn? Complete the following template:
The important thing about the first stage of demographic transition is: _____________ ;
but, the important thing about the fourth stage of demographic transition is: _____________ .