Title: KEY CONCEPT As the human population grows, the demand for Earth
1KEY CONCEPT As the human population grows, the
demand for Earths resources increases.
2Earths human population continues to grow.
- Earths human carrying capacity is unknown.
- It has changed over time.
- Todays human population of more than 6 billion
has exceeded earlier predictions - Some limit must exist
3- Technology has helped to increase Earths
carrying capacity.
- gas-powered farm equipment
- medical advancements
- In 1940 more than 40 infants died for every 1000
births - In 2002 only 7 infants died for every 1000 births
4The growing human population exerts pressure on
Earths natural resources.
- Nonrenewable resources are used faster than they
form. - coal
- Oil
- The growing use of limited resources will lead to
energy crisis in decades ahead unless
technologies are developed to use other forms of
energy.
5- Renewable resources cannot be used up or can
replenish themselves over time.
- Growing use of nonrenewable resources may lead to
a crisis. - Resources must be properly managed.
6Effective management of Earths resources will
help meet the needs of the future.
- Earths resources must be used responsibly.
- Careless use of resources makes them unavailable
to future generations. - Easter Island isan example ofirresponsibleresou
rce use.
7- 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
8- Several factors affect the size of the ecological
footprint.
- amount and efficiency of resource use
- amount and toxicity of waste produced
9KEY CONCEPT Fossil fuel emissions affect the
biosphere.
10Pollutants 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 (microscopic bits of dust,
metal and unburned fuel produced by industrial
processes) and ground-level ozone
11- 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
12Air pollution is changing Earths biosphere.
- The levels of atmospheric carbon dioxide rise and
fall over time. - High levels of carbon dioxide are typical of
Earths warmer periods.
13- The same way that greenhouse glass creates an
environment for plants to grow, the chemical
composition of Earths atmosphere plays an
important role in maintaining an environment that
is suitable for life. - Greenhouse gases Act as insulators and slow the
loss of heat - Water Vapor
- Carbon Dioxide
- Methane
- Greenhouse effect occurs when carbon dioxide,
water and methane molecules absorb energy
reradiated by Earths surface and slow the release
of this energy from Earths atmosphere.
14- Global warming refers to the trend of increasing
global temperatures. - Scientist can infer that the changes in
temperature are the result of increased levels of
greenhouse gases such as carbon dioxide, water
and methane. - Ecological disasters, such as increased flooding,
stronger tropical storms and the loss of
biodiversity, are just a few threats that may be
caused by global warming
15KEY CONCEPT Pollution of Earths freshwater
supply threatens habitat and health.
16Water pollution affects ecosystems.
- Pollution can put entire freshwater ecosystems at
risk. - - Runoff from farms and cities
- Disrupts the chemical balance
- Stimulation of plant an algae overgrowth can
drastically lower the levels of dissolved oxygen. - Fish populations die off
- Detritivores are not able to break down waste
17- Indicator species provide a sign of an
ecosystems health.
- top predators
- Aquatic indicator species show
- the direct effects of pollution.
18Biomagnification 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. - EX Mercury, Polychlorinated biphenyls
19KEY CONCEPT The impact of a growing human
population threatens biodiversity.
20Preserving 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
- When a species goes extinct
- it is gone forever.
- A loss of biodiversity makes it more difficult
for an ecosystem to handle future change.
21Loss 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
- To try and fix this problem, some states are
building overpasses or underpasses so that
wildlife can avoid busy roadways.
22- Habitat corridors are a solution to the problem.
- corridors can be road overpasses or underpasses
- allow species to move between different areas of
habitat
23Introduced 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.
24- Invasive species often push out native species.
- Burmese python (Florida Everglades)
- Originally from the tropical jungles of
Southeastern Asia
25- Invasive species often push out native species.
26- Invasive species often push out native species.
- kudzu (southeastern United States)
27KEY CONCEPT Conservation methods can help
protect and restore ecosystems.
28Sustainable development manages resources for
present and future generations.
- Sustainable development meets needs without
hurting future generations. - resources meet current needs
- resources 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 catches
- fishing gear review
- harvest reduction
- fishing bans
30Conservation 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. - Protection of that species means that other
species will also be protected. - the habitat in which the species lives must be
protected - other species are protected because they share
the ecosystem
31Protecting Earths resources helps protect our
future.
- The Environmental Protection Agency (EPA) was
created in 1970. - The EPA develops policies and regulations to
protect the environment. - Legislation helps to protect the environment and
endangered species. - Clean Air Act
- Clean Water Act
- Endangered Species Act
32- The National Park Service helps manage public
lands.
- The park system includes over 390 areas, covering
84 million acres.
33- There are several ways that people can help
protect the environment.
- control population growth
- develop sustainable technology and practices
- protect and maintain ecosystems