1. Population Growth

2. Population
all of the individuals of a species that live together in one place at one time

3. Population Characteristics
features that describe interactions between the population and its environment
Geographic Distribution
Population Density
Age Structure
Growth Rate

4. 1. Geographic Distribution
a population’s range or area that it inhabits

5. 2. Population Density
the number of individuals per unit area

6. 3. Age Structure the age distribution of a population
how young or old the population is
generally looks like a pyramid as a population is growing

7. 4. Growth Rate the speed of a population’s growth (or decline)
affected by four factors
Mortality
death rate
Natality
birth rate

8. 4. Growth Rate the speed of a population’s growth (or decline)
affected by four factors
Immigration
rate of new individuals entering the population who were born outside of the population
Emigration
rate of individuals leaving the population for another area

9. Linear vs. Exponential Growth

10. Exponential Growth
occurs when individuals continue to reproduce at a constant rate

11. Exponential Growth occurs under “ideal” conditions
unlimited food, water, shelter, etc.
protection from predators and disease

12. Logistic Growth
occurs when a population’s growth slows or stops following exponential growth
occurs because resources become less available

13. Carrying Capacity
the largest number of individuals an environment can support over an extended period of time

14. So what can cause a population’s growth rate to slow down or even decline?

15. Limiting Factors
any factor that causes population growth to decrease

16. Limiting Factors

17. Density Dependent a limiting factor that depends on population size
predation
competition
parasitism
disease

18. Density Independent
affect all populations similarly regardless of the population size
weather
natural disasters
human activities

19. Human Population Growth
Historical Overview
The size of the human population has increased over time. It has increased very quickly the last couple hundred years…Why???
Agriculture and Industry
Reliable Food Supply
Improved Sanitation
Medical and Health Care

20. Human Population Growth
Demography
scientific study of human populations

21. Human Population Growth
Demographic Transition
a dramatic change in birth and death rates

22. Human Population Growth

23. Age Structure Diagram
model for predicting future population growth or decline

24. Age Structure Diagram

25. Age Structure Diagram

26. Age Structure Diagram

27. Age Structure Diagram