Transcript Biology Chapter Sixteen: Human Impact on Ecosystems

Section One: Human Population
Growth and Natural Resources
 Earth’s Human Population
 Continues to grow
 What is the Earth’s carrying capacity?
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Current World Population: 7.4 Billion
Carrying capacity has increased with agriculture,
transportation, and medical advances and sanitation
Technology and antibiotics has also helped to increase
carrying capacity
Section One: Human Population
Growth and Natural Resources
Section One: Human Population
Growth and Natural Resources
 Human Population and Natural Resource Pressure
 More humans= more use of natural resources
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Nonrenewable resources: resources that are used faster than
they are formed
 Oil and Coal
Renewable Resources: cannot be used up or replenish
themselves over time
 Wind and Solar Energy
 Pollution and over use threaten drinking water as a renewable
resource
Section One: Human Population
Growth and Natural Resources
 Resource Management and Ecological Footprint
 Practicing Sustainable Usage of Resources
 Ecological Footprint: the amount of land necessary to
produce and maintain enough food and water, shelter,
energy, and waste
Section Two: Air Quality
 Pollution: any undesirable factor that is added to air,
water, or soil
 Air Pollutants
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Smog: a type of air pollution caused by the interaction of
sunlight with pollutants produced by fossil fuel emissions
Particulates: microscopic bits of dust, metal, and unburned
fuel that are produced by many different industrial processes
 Can be inhaled
Ground Level Ozone
 Produced by reaction of oxygen gas and nitrogen oxide
 Can be harmful to humans
Section Two: Air Quality
 Air Pollutants
 Acid Rain: a type of precipitation produced when
pollutants in the water cycle cause rain pH to drop
below normal levels
Section Two: Air Quality
 How Air Pollution Affects the Biosphere
 Greenhouse Effect: occurs when greenhouse gases
absorb reradiated energy by Earth’s surface and slow the
release of this energy from Earth’s atmosphere
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Greenhouse gases: carbon dioxide, water, CFCs, and methane
Make it harder for heat to be released back into the
atmosphere
Contributes to excessive global warming
 Global Warming: the trend of increasing global temperatures
 Threatens ecosystems
Section Two: Air Quality
Section Two: Air Quality
Section Three: Water Quality
 Water Pollution
 Raw sewage, toxic
chemicals, and trash can
all enter the water system
 Can lead to algal blooms
and eutrophication
 Indicator Species: a
species that provides a
sign of the quality of the
ecosystem’s environmental
condition
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Amphibians
Section Three: Water Quality
 Biomagnification
 A process in which a
pollutant moves up the
food chain, as predators
eat prey, accumulating
in higher concentrations
in the bodies of the
predators
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Has the greatest effect on
top level consumers
Section Four: Threats to
Biodiversity
 Preserving Biodiversity
 Decreasing biodiversity has an effect on all living
organisms and ecosystems
 Effects are long-term
 Extinctions is forever
Section Four: Threats to
Biodiversity
 Causes of Loss of Biodiversity
 Habitat Loss
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Habitat Fragmentation: a barrier forms that prevents an
organism from accessing its entire home range
Some states have built overpasses or underpasses for wildlife
 Introduced (Invasive) Species
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Any organism that was brought to the ecosystem as a result of
human actions
Usually have no natural predators and can outcompete the
native species
Can cause economic damage
Section Four: Threats to
Biodiversity
Section Four: Threats to
Biodiversity
Section Five: Conservation
 Sustainable Development
 A practice in which natural resources are used and
managed in a way that meets current needs without
hurting future generations
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Selective cutting instead of clear cutting trees
 Fishing industry examples:
 Rotation
 Fishing Gear Review
 Harvest Reduction
 Fishing Bans
Section Five: Conservation
 Conservation through
Umbrella Species
 Conservation practices
usually focus on one
species but benefit entire
ecosystems
 Umbrella Species:
protection of one species
leads to protection of a
wide range of other
species
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Ex. Manatees and marine
ecosystems
Section Five: Conservation
 Protecting Earth’s Resources and Our Future
 Earth’s resource provide $30 trillion a year in services
 Environmental Protection Agency (EPA)
 Environmental Laws (Clean Air Act)
 National Parks
 Controlling Birth Rate
 Using Less and Wasting Less