1. Are there too many people on the planet? How big of a number is 7 billion? Is 7 billion really that large? What does the most typical person look like?

2. A world of 7 billion people poses many challenges, and countless opportunities to make a positive difference. By 2045 global population is projected to reach nine billion. Can the planet take the strain? What's the population this minute?

3. Why is human population increasing? Not only are people living longer, but so many women across the world are now in their childbearing years—1.8 billion—that the global population will keep growing for another few decades at least, even though each woman is having fewer children than she would have had a generation ago. By 2050 the total number could reach 10.5 billion, or it could stop at eight billion—the difference is about one child per woman.

4. Explain the population age pyramids above, and their consequences for populations in developing and developed nations.

5. With the population still growing by about 80 million each year, it’s hard not to be alarmed. Right now water tables are falling, soil is eroding, glaciers are melting, and fish stocks are vanishing. Close to a billion people go hungry each day. Decades from now, there will likely be two billion more mouths to feed, mostly in poor countries. There will be billions more people wanting and deserving to boost themselves out of poverty. If they follow the path blazed by wealthy countries— clearing forests, burning coal and oil, freely scattering fertilizers and pesticides—they too will be stepping hard on the planet’s natural resources. How exactly is this going to work? What does the future hold for us?

6. Are we destined for doom? The number of people does matter, but how people consume resources matters a lot more. Some of us leave much bigger footprints than others. The central challenge for the future of people and the planet is how to raise more of us out of poverty while reducing the impact each of us has on the planet.

7. Population History

9. When will our population stop growing? Brainstorm some reasons that would limit the population from increasing on earth.

10. Carrying Capacity The maximum number of individuals of a particular species that the environment can normally and consistently support. Populations are usually higher and lower than the carrying capacity. The supply of resources change so the population changes. Ex. Grasshoppers feed on grass. – If the part of the meadow burns, & the insects food resources are lowered, then the carrying capacity declines. – When there is plentiful rain, the grass grows and the carrying capacity rises.

11. Carrying Capacity Sometimes the carrying capacity drops very quickly and the population experiences a crash. This is called a population crash. A population crash is a dramatic decline in the size of population over a short period of time. Anytime resources are limited, the population drops.

12. Exponential Growth / J Curve There is no limit to a population’s size. Occurs when there are plenty of resources available.

13. Logistical Growth / S Curve A limiting factor has an effect on a population’s growth. Begins with a period of slow growth, followed by exponential growth. Population eventually levels off at a size the environment can support.

14. Limiting Factors Something that can change or limit population growth What are some limiting factors for plants? What are some limiting factors for animals?

15. Types of Limiting Factors 1.Density-Dependent Limiting Factors – limiting factors that are affected by the number of individuals in a given area. a.Competition b.Parasitism c.Disease 2.Density- Independent Limiting Factors – limiting factors that limit a population’s growth REGARDLESS of the density of the population. a. Unusual weather b. Natural disasters c. Human activity

16. Density dependent or independent?

18. Graph Analysis What happens to the moose population as the wolf population increases? What happens to the moose population as the wolf population decreases? Is there something in the data to suggest that the wolf population crashed? In what way does the data suggest that something other than availability of prey caused the wolf population to crash? Is there something in the data to suggest that the moose population crashed? What might have caused the moose population to crash?

19. What happens to the moose population as the wolf population increases? It decreases What happens to the moose population as the wolf population decreases? It increases Is there something in the data to suggest that the wolf population crashed? A dramatic drop in the wolf population starting about 1978. In what way does the data suggest that something other than availability of prey caused the wolf population to crash? The wolf population continued to fall even though the moose population rebounded dramatically and plenty of prey was available. Is there something in the data to suggest that the moose population crashed? A dramatic drop in the moose population starting about 1994. What might have caused the moose population to crash? With few predators to control their numbers, the moose exceeded the carrying capacity of their environment.

20. Competition between the SAME species, also happens!

21. Biotic Potential Biotic potential is the maximum reproductive capacity of a population if resources are unlimited.