Download 16.1 Human Population Growth And Natural Resources

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
Earth’s human population continues to grow.
• Earth’s human carrying capacity is unknown.
16.1 Human Population Growth And Natural
Resources
• Technology has helped to increase Earth’s carrying
capacity.
– gas-powered farm equipment
– medical advancements
16.1 Human Population Growth And Natural
Resources
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
Resources
• 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
Resources
• 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
Resources
• 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
Resources
Give 3 examples of how technology has influenced
human population growth
• Advances in medicine have reduced infant mortality and
prolonged life spans
• Industrial technologies have made transportation and
agriculture more productive and easier, allowing for
easier food production and distribution
• Plumbing and sewage treatment have improved
sanitation, reducing incidence of water born illness
16.1 Human Population Growth And Natural
Resources
What is the difference between renewable and
nonrenewable resources
Renewable Resources
Nonrenewable Resources
• Are difficult to replenish in
• Can be replenished by
a time span meaningful to
Earths natural processes
humans
16.1 Human Population Growth And Natural
Resources
What factors can limit the growth of the human
population?
•
•
•
•
•
Disease
Drought
Overexploitation of limited resources
Crop pests
War
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
16.2
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
Resources
• 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
16.1 Human Population
Resources
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
16.1 Human Population
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
16.2
AirGrowth
Quality And Natural
16.1 Human Population
Resources
• Global warming refers to the trend of increasing global
temperatures.
North Pole
16.2
AirGrowth
Quality And Natural
16.1 Human Population
Resources
Name and describe 2 ways in which pollution affects
ecosystems
• Pollution can result in smog and acid rain
• Smog is caused by the interaction of sunlight with
pollutants produced by fossil fuel emissions
• Acid rain results from the mixture of these emissions with
water
16.2
AirGrowth
Quality And Natural
16.1 Human Population
Resources
How does the greenhouse effect keep Earth warm?
• Infrared energy Radiating from Earths surface is
absorbed by greenhouse molecules such as water,
carbon dioxide, and methane.
• This energy, also called heat, is then released and
absorbed by other molecules of Earths surface or the
atmosphere.
16.2
AirGrowth
Quality And Natural
16.1 Human Population
Resources
Explain how a build-up of CO2 in the atmosphere could
increase Earths global temperature.
• With more greenhouse molecules in the atmosphere,
less heat would be allowed to escape, causing Earth to
become warmer.
16.2
AirGrowth
Quality And Natural
16.1 Human Population
Resources
Greenhouse gasses are found close to earths surface
and high above in the atmosphere. Name 2 important
functions of greenhouse gasses at Earths surface.
• At Earths surface water vapor condenses to form
precipitation which is part of the hydrologic cycle
• Carbon dioxide is a necessary reactant for
photosynthesis
16.2
AirGrowth
Quality And Natural
16.1 Human Population
Resources
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?
• If increased water temperatures kill the phytoplankton,
the lowest trophic levels will be gone and the food webs
will probably collapse
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
Resources
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
16.1 Human Population
Growth
Resources
How do PCBs affect bird populations through
biomagnification?
• PCBs travel up through trophic structure of an ecosystem
and accumulate in large amounts in the eggs of large
birds.
• PCBs can negatively impact growth and development
within the egg, causing
– Genetic mutations
– Deformities
– Death
• The population of birds may crash as a result
16.3
Water
QualityAnd Natural
16.1 Human Population
Growth
Resources
Would a buffalo or a mountain lion be more affected by
biomagnification? Why?
• A mountain lion would be more affected because it is
higher on the food chain and would ingest more
contaminants from its food supply
16.3
Water
QualityAnd Natural
16.1 Human Population
Growth
Resources
How does the biomagnification pyramid compare with
the energy pyramid?
• They are opposite
• Energy decreases as you move up the food chain, but
pollution increases
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
16.1 Human Population
Resources
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
16.1 Human Population
Resources
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
Resources
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
Resources
• Habitat corridors are a solution to the problem.
– corridors can be road overpasses or underpasses
– allow species to move between different areas of
habitat
16.4
Threats to Growth
biodiversityAnd Natural
16.1 Human Population
Resources
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
16.1 Human Population
Resources
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
Resources
List reasons that biodiversity is important to humans
• A loss of diversity could mean a loss of food, medicine,
and economic activity
16.4
Threats to Growth
biodiversityAnd Natural
16.1 Human Population
Resources
How does habitat fragmentation affect migrating bird
populations?
• Birds need large areas of land or water on which to rest
and feed during long migrations.
• If these habitats aren’t available they may not be able to
complete a migration
16.4
Threats to Growth
biodiversityAnd Natural
16.1 Human Population
Resources
What types of damage can introduced species cause?
• Introduced species can disrupt ecosystems, threaten
human health, and physically dominate or overtake
waterways and human-made structures
16.4
Threats to Growth
biodiversityAnd Natural
16.1 Human Population
Resources
How could continued fragmentation reduce
biodiversity?
• If species are cut off from habitats they need for survival
or reproduction, they could become extinct, thereby
reducing biodiversity
16.1 Human Population Growth And Natural
Resources
Due Wednesday: In your Study guide Workbook
Chapters 13 & 14
Chapters 15 & 16
Pages
Numbers
Pages
Numbers
133
1-5
155-156
All
134
10
157
1-4
135
All
158
All
137-144
All
161
5-6
145-146
1-6
162
all
147
1-5
148
7-10
150
6-13
151
1-4
152
6-9
153-154
1&4