Transcript 16.1 Human Population Growth And Natural Resources KEY CONCEPT

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
Objectives
• Summarize the current state and effects of human
population growth
• Explain the importance of effective resource
management
16.1 Human Population Growth And Natural
Resources
Vocabulary
• Nonrenewable resource
• Renewable resource
• Ecological footprint
16.1 Human Population Growth And Natural
Resources
Earth’s human population continues to grow.
• Earth’s human carrying capacity is unknown.
16.1 Human Population Growth And Natural
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• Technology has helped to increase Earth’s carrying
capacity.
– gas-powered farm equipment
– medical advancements
16.1 Human Population Growth And Natural
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The growing human population exerts pressure on
Earth’s natural resources.
• Nonrenewable resources are used faster than they form.
– coal
– oil
16.1 Human Population Growth And Natural
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• 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.
16.1 Human Population Growth And Natural
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• 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
16.1 Human Population Growth And Natural
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• Several factors affect the size of the ecological footprint.
– amount and efficiency of resource use
– amount and toxicity of waste produced
16.1 Human Population Growth And Natural
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Give 3 examples of how technology has influenced
human population growth
16.1 Human Population Growth And Natural
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What is the difference between renewable and
nonrenewable resources
Renewable Resources
Nonrenewable Resources
16.1 Human Population Growth And Natural
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What factors can limit the growth of the human
population?
16.2
AirGrowth
Quality And Natural
16.1 Human Population
Resources
KEY CONCEPT
Fossil fuel emissions affect the biosphere.
16.2
AirGrowth
Quality And Natural
16.1 Human Population
Resources
Objective
• Describe the sources, types, and effects of pollution
• Explain how air pollution contributes to acid rain
16.1 Human Population Growth And Natural
Resources
Vocabulary
•
•
•
•
•
•
Pollution
Smog
Particulate
Acid rain
Greenhouse effect
Global warming
16.2
AirGrowth
Quality And Natural
16.1 Human Population
Resources
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
AirGrowth
Quality And Natural
16.1 Human Population
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• 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
AirGrowth
Quality And Natural
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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
AirGrowth
Quality And Natural
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Resources
• 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
carbon dioxide
(CO )
gas molecules
methane (CH )
water (H O)
rerelease
infrared
radiation
2
4
2
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AirGrowth
Quality And Natural
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• Global warming refers to the trend of increasing global
temperatures.
North Pole
16.2
AirGrowth
Quality And Natural
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Name and describe 2 ways in which pollution affects
ecosystems
16.2
AirGrowth
Quality And Natural
16.1 Human Population
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How does the greenhouse effect keep Earth warm?
16.2
AirGrowth
Quality And Natural
16.1 Human Population
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Explain how a build-up of CO2 in the atmosphere could
increase Earths global temperature.
16.2
AirGrowth
Quality And Natural
16.1 Human Population
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Greenhouse gasses are found close to earths surface
and high above in the atmosphere. Name 2 important
functions of greenhouse gasses at Earths surface.
16.2
AirGrowth
Quality And Natural
16.1 Human Population
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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?
16.3
Water
QualityAnd Natural
16.1 Human Population
Growth
Resources
KEY CONCEPT
Pollution of Earth’s freshwater supply threatens
habitat and health.
16.3
Water
QualityAnd Natural
16.1 Human Population
Growth
Resources
Objectives
• Describe how water pollution affects ecosystems
• Explain how biomagnification causes accumulation of
toxins in food chains
16.3
Water
QualityAnd Natural
16.1 Human Population
Growth
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Vocabulary
• Indicator species
• biomagnification
16.3
Water
QualityAnd Natural
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Growth
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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
QualityAnd Natural
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Growth
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2 Types of Pollutants that undergo Biomagnification are
PCBs and DDT
• Polychlorinated biphenyls
(PCBs) were widely used as
coolant fluids
• PCBs can negatively impact
growth and development within
the egg, causing
– Genetic mutations
– Deformities
– Death
16.3
Water
QualityAnd Natural
16.1 Human Population
Growth
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DDT was made available for use as an agricultural
insecticide after WWII
• In 1962, Silent Spring by American biologist Rachel
Carson was published.
– The book suggested that DDT and other pesticides
may cause cancer and that their agricultural use was a
threat to wildlife, particularly birds.
– Its publication was one of the signature events in the
birth of the environmental movement, and resulted in a
large public outcry that eventually led to DDT being
banned for agricultural use in the US in 1972.
– The US ban on DDT is cited by scientists as a major
factor in the comeback of the bald eagle, and the
peregrine falcon from near-extinction in the contiguous
US
16.3
Water
QualityAnd Natural
16.1 Human Population
Growth
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How do PCBs affect bird populations through
biomagnification?
16.3
Water
QualityAnd Natural
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Growth
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Would a buffalo or a mountain lion be more affected by
biomagnification? Why?
16.3
Water
QualityAnd Natural
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Growth
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How does the biomagnification pyramid compare with
the energy pyramid?
16.4
Threats to Growth
biodiversityAnd Natural
16.1 Human Population
Resources
KEY CONCEPT
The impact of a growing human population threatens
biodiversity.
16.4
Threats to Growth
biodiversityAnd Natural
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Objectives
• Assess the consequences of loss of biodiversity
• Explain how loss of habitat and introduced species affect
ecosystems and biodiversity
16.4
Threats to Growth
biodiversityAnd Natural
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Vocabulary
• Habitat fragmentation
• Introduced species
16.4
Threats to Growth
biodiversityAnd Natural
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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
16.4
Threats to Growth
biodiversityAnd Natural
16.1 Human Population
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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
16.1 Human Population Growth And Natural
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• Habitat corridors are a solution to the problem.
– corridors can be road overpasses or underpasses
– allow species to move between different areas of
habitat
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Threats to Growth
biodiversityAnd Natural
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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 species
can have an
environmental
and economic
impact.
16.4
Threats to Growth
biodiversityAnd Natural
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Invasive species often push out native species.
Burmese python (Florida
Everglades) & mice
(Australia)
kudzu (southeastern United
States)
16.4
Threats to Growth
biodiversityAnd Natural
16.1 Human Population
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List reasons that biodiversity is important to humans
16.4
Threats to Growth
biodiversityAnd Natural
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How does habitat fragmentation affect migrating bird
populations?
16.4
Threats to Growth
biodiversityAnd Natural
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What types of damage can introduced species cause?
16.4
Threats to Growth
biodiversityAnd Natural
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How could continued fragmentation reduce
biodiversity?