1. CHAPTER 5 Populations

2. What is a population? A population is a group of ONE kind of organism. Examples:  Herd of cattle  Pack of geese

3. Population Density Population Density describes how many individuals live in a given area. Formula  Pop. Den. = # Individuals Area

4. Population Density Word Problems Example 1: – There are 60 flowers in a garden that is 3 feet by 4 feet. What is the population density per square foot? Example 2: – Given that the population density of a neighborhood is 10 people per square mile, how many people would live in a city with an area of 10 square miles?

5. Population Growth Populations can change in size for any of the following reasons:  Reproduction  Death  Immigration = moves TO location  Emigration = moves AWAY from location  Other Circumstances

6. Exponential Growth Curve When organisms reproduce very quickly, and there seems to be NO limits on population growth, the graph is said to be exponential. Sometimes this is called a J-curve because it looks like a J.

7. Logistic Growth Curve When organisms reproduce very quickly, and there seems to be limits on population growth, the graph is said to be logistic. Sometimes this is called an S-curve because it looks like a sideways S.

8. Logistic Growth (cont) The level that the graph plateaus at is called the carrying capacity. Carrying capacity describes the maximum number of individuals the environment can sustain given limited resources / factors.

9. Density-Independent Factors Density-Independent Factors are factors that affect all populations in similar ways. Examples:  Weather / Seasonal Cycles  Natural Disasters  Human Activities

10. Density-Dependent Factors Density-Dependent Factors usually affect populations with high population densities. Examples:  Competition  Predation  Disease  Parasitism

11. Are these density-independent or density- dependent? Example 1: – A flu outbreak is spreading through a large high school. Over 200 students become ill. Example 2: – A tornado funnel touches down in a small farming community. The tornado destroys a third of the homes and businesses. Example 3: – Several lions and hyenas gather near a small watering hole. There is limited water, so the lions and hyenas fight each other.

12. Human Population Growth Human population growth increased very slowly until the Industrial Revolution in the 1800s. It has since skyrocketed to over 7 billion people on Earth.

13. Patterns of Human Population Growth Demography is the study of human populations. Birth rate is the number of births per 1000 people. Death rate is the number of deaths per 1000 people.

14. Demographic Transition Stage 1 = High birth and death rates Stage 2 = High birth rate, slowing death rate

15. Demographic Transition Stage 3 = Slowing birth rate, low death rate Stage 4 = Low birth and death rates

16. Age-Structure Diagrams Age-structure diagrams (aka p0pulation pyramids) are modified histograms (bar graphs) that display the subgroups of a country based off of gender and age group. The youngest individuals are on the bottom, and the oldest individuals are on the top. Males are on the left, and females are on the right.

17. Age-Structure Diagrams Depending on how well-developed a country is, the age-structure pyramid may have a different shape.  Rapidly growing countries (developing) have a very triangularly shaped pyramid with a very side base and narrow top.  Slowly growing countries (moderately developing) have a triangular shape, but the bottom is not as wide and the top is wider.  Negatively growing countries (well developed) have a small base and may seem almost uniform throughout the pyramid

18. Age-Structure Diagrams

19. CHAPTER 6 Human Impact on the Environment

20. Human Activities throughout History Hunter-Gatherers Agriculture Industrial Growth & Urban Development

21. Biodiversity Biodiversity describes the range of differences in living things in terms of ecosystems, species, and genetics. Renewable resources are materials that can be reused and replenished whereas nonrenewable resources cannot.

22. Extinction & Endangerment Habitat Fragmentation Threats to Biodiversity & Natural Resources

23. Invasive Species Soil Erosion Threats to Biodiversity & Natural Resources

24. Desertification Pollution & Biological Magnification Threats to Biodiversity & Natural Resources

25. Deforestation Overfishing Threats to Biodiversity & Natural Resources

26. Controlled Aquaculture Air Pollution (smog, acid rain, etc) Threats to Biodiversity & Natural Resources

27. Ozone Depletion Global Warming Threats to Biodiversity & Natural Resources

28. Current Solutions Conservation efforts are underway to preserve ecosystems as they currently are. Many businesses and governments are seeking ecological sustainability, meaning they will function in a way that will be able to help the environment while they run efficiently.