16.1 Human Population Growth And Natural Resources KEY CONCEPT As the human population grows, the demand for Earth’s resources increases

16.1 Human Population Growth And Natural Resources

KEY CONCEPT As the human population grows, the demand for Earth’s resources increases.


Objectives

• Summarize the current state and effects of human population growth

• Explain the importance of effective resource management


Earth’s human population continues to grow.

• Earth’s human carrying capacity is unknown.


• Technology has helped to increase Earth’s carrying capacity.– gas-powered farm equipment– medical advancements


The growing human population exerts pressure on Earth’s natural resources.

• Nonrenewable resources are used faster than they form.– coal– oil


• Renewable resources cannot be used up or can replenish themselves over time.– wind– water– sunlight

• Growing use of nonrenewable resources may lead to a crisis.

• Resources must be properly managed.


• An ecological footprint is the amount of land needed to support a person.

• The land must produce and maintain enough– food and water– shelter– energy– waste


• Several factors affect the size of the ecological footprint.– amount and efficiency of resource use – amount and toxicity of waste produced


Give 3 examples of how technology has influenced human population growth

• Advances in medicine have reduced infant mortality and prolonged life spans

• Industrial technologies have made transportation and agriculture more productive and easier, allowing for easier food production and distribution

• Plumbing and sewage treatment have improved sanitation, reducing incidence of water born illness


What is the difference between renewable and nonrenewable resources

Renewable Resources

• Can be replenished by Earths natural processes

Nonrenewable Resources

• Are difficult to replenish in a time span meaningful to humans


What factors can limit the growth of the human population?

• Disease• Drought• Overexploitation of limited resources• Crop pests• War


KEY CONCEPT Fossil fuel emissions affect the biosphere.

16.2 Air Quality


Objective

• Describe the sources, types, and effects of pollution

• Explain how air pollution contributes to acid rain

16.2 Air Quality


Pollutants accumulate in the air.

• Pollution is any undesirable factor added to the air, water, or soil.

• Smog is one type of air pollution.– sunlight interacts with

pollutants in the air– pollutants produced by fossil

fuel emissions– made of particulates and

ground-level ozone

16.2 Air Quality


• Smog can be harmful to human health.• Acid rain is caused by fossil fuel emissions.

– produced when pollutants in the water cycle cause rain pH to drop

– can lower the pH of a lake or stream– can harm trees

16.2 Air Quality


Air pollution is changing Earth’s biosphere.

• The levels of atmospheric carbon dioxide rise and fall over time.

• High levels of carbon dioxide are typical of Earth’s warmer periods.

16.2 Air Quality


• The greenhouse effect slows the release of energy from Earth’s atmosphere.– sunlight penetrates Earth’s atmosphere– energy is absorbed and reradiated as heat– greenhouse gases absorb longer wavelengths– Greenhouse

gas moleculesrereleaseinfraredradiation

methane (CH4) water (H2O)

carbon dioxide(CO2)

16.2 Air Quality


• Global warming refers to the trend of increasing global temperatures.

North Pole

16.2 Air Quality


Name and describe 2 ways in which pollution affects ecosystems

• Pollution can result in smog and acid rain

• Smog is caused by the interaction of sunlight with pollutants produced by fossil fuel emissions

• Acid rain results from the mixture of these emissions with water

16.2 Air Quality


How does the greenhouse effect keep Earth warm?

• Infrared energy Radiating from Earths surface is absorbed by greenhouse molecules such as water, carbon dioxide, and methane.

• This energy, also called heat, is then released and absorbed by other molecules of Earths surface or the atmosphere.

16.2 Air Quality


Explain how a build-up of CO2 in the atmosphere could increase Earths global temperature.

• With more greenhouse molecules in the atmosphere, less heat would be allowed to escape, causing Earth to become warmer.

16.2 Air Quality


Greenhouse gasses are found close to earths surface and high above in the atmosphere. Name 2 important functions of greenhouse gasses at Earths surface.

• At Earths surface water vapor condenses to form precipitation which is part of the hydrologic cycle

• Carbon dioxide is a necessary reactant for photosynthesis

16.2 Air Quality


Ocean producers such as phytoplankton are an important part of food webs, but they require a specific temperature range to survive. How might increased water temperature affect these ocean food webs?

• If increased water temperatures kill the phytoplankton, the lowest trophic levels will be gone and the food webs will probably collapse

16.2 Air Quality


KEY CONCEPT Pollution of Earth’s freshwater supply threatens habitat and health.

16.3 Water Quality


Objectives

• Describe how water pollution affects ecosystems

• Explain how biomagnification causes accumulation of toxins in food chains

16.3 Water Quality


Biomagnification causes accumulation of toxins in the food chain.

• Pollutants can move up the food chain.– predators eat contaminated

prey– pollution accumulates at

each stage of the food chain• Top consumers, including

humans, are most affected.

16.3 Water Quality


How do PCBs affect bird populations through biomagnification?

• PCBs travel up through trophic structure of an ecosystem and accumulate in large amounts in the eggs of large birds.

• PCBs can negatively impact growth and development within the egg, causing – Genetic mutations– Deformities– Death

• The population of birds may crash as a result

16.3 Water Quality


Would a buffalo or a mountain lion be more affected by biomagnification? Why?

• A mountain lion would be more affected because it is higher on the food chain and would ingest more contaminants from its food supply

16.3 Water Quality


How does the biomagnification pyramid compare with the energy pyramid?

• They are opposite

• Energy decreases as you move up the food chain, but pollution increases

16.3 Water Quality


KEY CONCEPT The impact of a growing human population threatens biodiversity.

16.4 Threats to biodiversity


Objectives

• Assess the consequences of loss of biodiversity

• Explain how loss of habitat and introduced species affect ecosystems and biodiversity



Preserving biodiversity is important to the future of the biosphere.

• The loss of biodiversity has long-term effects.– loss of medical and technological advances– extinction of species– loss of ecosystem stability



Loss of habitat eliminates species.

• Habitat fragmentation prevents an organism from accessing its entire home range.– occurs when a barrier forms within the habitat– often caused by human development



• Habitat corridors are a solution to the problem.

– corridors can be road overpasses or underpasses– allow species to move between different areas of

habitat


Introduced species can disrupt stable relationships in an ecosystem.

• An introduced species is one that is brought to an ecosystem by humans.– accidental– purposeful

• Invasive speciescan have anenvironmentaland economicimpact.



Invasive species often push out native species.

Burmese python (Florida Everglades) & mice (Australia)

kudzu (southeastern United States)



List reasons that biodiversity is important to humans

• A loss of diversity could mean a loss of food, medicine, and economic activity



How does habitat fragmentation affect migrating bird populations?

• Birds need large areas of land or water on which to rest and feed during long migrations.

• If these habitats aren’t available they may not be able to complete a migration



What types of damage can introduced species cause?

• Introduced species can disrupt ecosystems, threaten human health, and physically dominate or overtake waterways and human-made structures



How could continued fragmentation reduce biodiversity?

• If species are cut off from habitats they need for survival or reproduction, they could become extinct, thereby reducing biodiversity



Due Wednesday: In your Study guide WorkbookChapters 13 & 14

Pages Numbers

133 1-5

134 10

135 All

137-144 All

145-146 1-6

147 1-5

148 7-10

150 6-13

151 1-4

152 6-9

153-154 1 & 4

Chapters 15 & 16

Pages Numbers

155-156 All

157 1-4

158 All

161 5-6

162 all

Documents

16.1 Human Population Growth And Natural Resources KEY CONCEPT As the human population grows, the demand for Earth’s resources increases