Presentation on theme: "Human Impacts on the Environment"— Presentation transcript:
1 Human Impacts on the Environment Chapter 16Human Population and Natural ResourcesAir & Water QualityThreats to BiodiversityConservation
2 KEY CONCEPT As the human population grows, the demand for Earth’s resources increases.
3 Earth’s human population continues to grow. Earth’s human carrying capacity is unknown.
4 Technology has helped to increase Earth’s carrying capacity. gas-powered farm equipmentmedical advancements
5 The growing human population exerts pressure on Earth’s natural resources. Nonrenewable resources are used faster than they form.coaloil
6 Renewable resources cannot be used up or can replenish themselves over time. windwatersunlightGrowing use of nonrenewable resources may lead to a crisis.Resources must be properly managed.
7 Effective management of Earth’s resources will help meet the needs of the future. Earth’s resources must be used responsibly.Careless use of resources makes them unavailable to future generations.Easter Island is an example of irresponsible resource use.
8 An ecological footprint is the amount of land needed to support a person. The land must produce and maintain enoughfood and watershelterenergywaste
9 Several factors affect the size of the ecological footprint. amount and efficiency of resource useamount and toxicity of waste produced
10 KEY CONCEPT Fossil fuel emissions affect the biosphere.
11 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 airpollutants produced by fossil fuel emissionsmade of particulates and ground-level ozone
12 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 dropcan lower the pH of a lake or streamcan harm trees
13 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.
14 The greenhouse effect slows the release of energy from Earth’s atmosphere. sunlight penetrates Earth’s atmosphereenergy is absorbed and reradiated as heatgreenhouse gases absorb longer wavelengthsGreenhouse gas molecules rerelease infrared radiationmethane (CH4)water (H2O)carbon dioxide (CO2)
15 KEY CONCEPT Pollution of Earth’s freshwater supply threatens habitat and health.
16 Water pollution affects ecosystems. Pollution can put entire freshwater ecosystems at risk.
17 Indicator species provide a sign of an ecosystem’s health. amphibianstop predators
18 Biomagnification causes accumulation of toxins in the food chain. Pollutants can move up the food chain.predators eat contaminated preypollution accumulates at each stage of the food chainTop consumers, including humans, are most affected.
19 KEY CONCEPT The impact of a growing human population threatens biodiversity.
20 Preserving biodiversity is important to the future of the biosphere. The loss of biodiversity has long-term effects.loss of medical and technological advancesextinction of speciesloss of ecosystem stability
21 Loss of habitat eliminates species. Habitat fragmentation prevents an organism from accessing its entire home range.occurs when a barrier forms within the habitatoften caused by human development
22 Habitat corridors are a solution to the problem. corridors can be road overpasses or underpassesallow species to move between different areas of habitat
23 Introduced species can disrupt stable relationships in an ecosystem. An introduced species is one that is brought to an ecosystem by humans.accidentalpurposefulInvasive species can have an environmental and economic impact.
24 Invasive species often push out native species. Burmese python (Florida Everglades)
25 Invasive species often push out native species. mice (Australia)
26 Invasive species often push out native species. kudzu (southeastern United States)
27 KEY CONCEPT Conservation methods can help protect and restore ecosystems.
28 Sustainable development manages resources for present and future generations. Sustainable development meets needs without hurting future generations.resources meet current needsresources will still be available for future use
29 The timber industry has started to adopt sustainable practices. Global fisheries have adopted several sustainable practices.rotation of catchesfishing gear reviewharvest reductionfishing bans
30 Conservation practices focus on a few species but benefit entire ecosystems. The Endangered Species Act works to protect individual species from extinction.A listed species is often called an umbrella species.the habitat in which the species lives must be protectedother species are protected because they share the ecosystem
31 The National Park Service helps manage public lands. The park system includes over 390 areas, covering 84 million acres.
32 There are several ways that people can help protect the environment. control population growthdevelop sustainable technology and practicesprotect and maintain ecosystems