Slide Human impact on Ecosystems
Bạn đang xem bản rút gọn của tài liệu. Xem và tải ngay bản đầy đủ của tài liệu tại đây (2.7 MB, 34 trang )
Human Impact on Ecosystems
Mr. Garside
Mr. Jones
Mr. Schumacher
Mr. Wilcox
© 2008 McDougal Littell
Human Impact on Ecosystems
I. As the human population grows, the demand for
Earth’s resources increases.
Human Impact on Ecosystems
A. Earth’s human population continues to grow.
1. Earth’s human carrying capacity is unknown.
Human Impact on Ecosystems
2. Technology has helped to increase Earth’s carrying
capacity.
a. gas-powered farm equipment
b. medical advancements
Human Impact on Ecosystems
B. The growing human population exerts pressure on
Earth’s natural resources.
1. Nonrenewable resources are used faster than they form.
a. coal
b. oil
Human Impact on Ecosystems
2. Renewable resources cannot be used up or can replenish
themselves over time.
a. wind
b. water
c. sunlight
3. Growing use of
nonrenewable
resources may
lead to a crisis.
4. Resources must
be properly
managed.
Human Impact on Ecosystems
C. Effective management of Earth’s resources will help
meet the needs of the future.
1. Earth’s resources must be used responsibly.
2. Careless use of resources makes them unavailable to
future generations.
3. Easter Island is
an example of
irresponsible
resource use.
Human Impact on Ecosystems
4. An ecological footprint is the amount of land needed to
support a person.
5. The land must produce and maintain enough
a. food and water
b. shelter
c. energy
d. waste
Human Impact on Ecosystems
6. Several factors affect the size of the ecological footprint.
a. amount and efficiency of resource use
b. amount and toxicity of waste produced
Human Impact on Ecosystems
II.Fossil fuel emissions affect the biosphere.
Human Impact on Ecosystems
A. Pollutants accumulate in the air.
1. Pollution is any undesirable
factor added to the air, water, or
soil.
2. Smog is one type of air
pollution.
a. sunlight interacts with
pollutants in the air
b. pollutants produced by fossil
fuel emissions
c. made of particulates and
ground-level ozone
Human Impact on Ecosystems
3. Smog can be harmful to human health.
4. Acid rain is caused by fossil fuel emissions.
a. produced when pollutants in the water cycle cause
rain pH to drop
b. can lower the pH of a lake or stream
c. can harm trees
Human Impact on Ecosystems
A. Air pollution is changing Earth’s biosphere.
1. The levels of atmospheric carbon dioxide rise and fall
over time.
2. High levels of carbon dioxide are typical of Earth’s warmer
periods.
Human Impact on Ecosystems
3. The greenhouse effect slows the release of energy from
Earth’s atmosphere.
a. sunlight penetrates Earth’s atmosphere
b. energy is absorbed and reradiated as heat
c. greenhouse gases absorb longer wavelengths
d. Greenhouse
carbon dioxide
(CO )
gas molecules
methane (CH )
water (H O)
rerelease
infrared
radiation
2
4
2
Human Impact on Ecosystems
4. Global warming refers to the trend of increasing global
temperatures.
North Pole
Human Impact on Ecosystems
III. Pollution of Earth’s freshwater supply threatens
habitat and health.
Human Impact on Ecosystems
A. Water pollution affects ecosystems.
1. Pollution can put entire freshwater ecosystems at risk.
Human Impact on Ecosystems
2. Indicator species provide a sign of an ecosystem’s health.
a. amphibians
b. top predators
Human Impact on Ecosystems
B. Biomagnification causes accumulation of toxins in the
food chain.
1. Pollutants can move up the
food chain.
a. predators eat
contaminated prey
b. pollution accumulates at
each stage of the food
chain
2. Top consumers, including
humans, are most affected.
Human Impact on Ecosystems
IV. The impact of a growing human population threatens
biodiversity.
Human Impact on Ecosystems
A. Preserving biodiversity is important to the future of the
biosphere.
1. The loss of biodiversity has long-term effects.
a. loss of medical and technological advances
b. extinction of species
c. loss of ecosystem stability
Human Impact on Ecosystems
B. Loss of habitat eliminates species.
1. Habitat fragmentation prevents an organism from
accessing its entire home range.
a. occurs when a barrier forms within the habitat
b. often caused by human development
Human Impact on Ecosystems
2. Habitat corridors are a solution to the problem.
– corridors can be road overpasses or underpasses
– allow species to move between different areas of
habitat
Human Impact on Ecosystems
C. Introduced species can disrupt stable relationships in an
ecosystem.
1. An introduced species is one that is brought to an
ecosystem by humans.
a. accidental
b. purposeful
2. Invasive species
can have an
environmental
and economic
impact.
Human Impact on Ecosystems
3. Invasive species often push out native species.
a. Burmese python (Florida Everglades)
