CHAPTER 6 HUMANS IN THE BIOSPHERE

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CHAPTER 6HUMANS IN THE BIOSPHERE
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SECTION 1 A CHANGING LANDSCAPE
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Key Concept Question

• What types of human activities can affect the
  biosphere?

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• What is carrying capacity?
• the largest number of individuals that an
  environment can support
• What do you think would be the
• consequences of exceeding Earths
• carrying capacity?
• overcrowding, shortage of food and water,
  shortage of fuel, malnutrition, increased disease

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Humans and the Environment

• Humans now live in almost every kind of ecosystem
  on Earth.
• As human population increases, the impact of
  humans on the environment increases.
• Humans are a part of the environment and can
  affect the resilience of the environment. The
  more that the human population grows, the more
  resources from the environment we will need to
  survive.

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• Earth is an interconnected planet we depend on
  the environment, and the environment is affected
  by our actions.
• Learning about this connectedness helps us care
  for the environment and ensures that the
  environment will continue to support us and other
  species on Earth.

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Visual Concept Human Population
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What types of human activities can affect the
biosphere?

• hunting and gathering
• agriculture
• industry
• urban development

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According to a recent study, human activity uses
as much energy as all of Earths other
multicellular species
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• Lets think about how humans have changed
  throughout history.

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MONOCULTURE

• large fields were cleared, plowed, and planted
  with a single crop year-after-year.
• needed irrigation
• chemical fertilizers
• pesticides needed
• human and animal power replaced by machines

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What are the advantages of using agricultural
machines such as tractors and harvesting combines?

• Vast acreages can be plowed, sown, and harvested
  in less time and with fewer people enabling
  farmers to produce large crops

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What are the disadvantages?

• initial cost, and cost of repairs and maintenance
• increased energy resources are used
• release of exhaust gas into the air
• noise pollution

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Results of the Industrial Revolution during 1800s

• reliance on fossil fuels
• increased use of mineral resources
• large-scale production of manufactured goods

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Suburban sprawl

• The spread of suburban communities across America
  

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• Problems
• large amounts of waste that needs to be disposed
  of
• consumes farmland
• consumes natural habitats
• places stress on native plants and animals

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Key Concept Question

• What types of human activities can affect the
  biosphere?
• hunting and gathering
• agriculture
• industry
• urban development

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SECTION 2 RENEWABLE AND NONRENEWABLE RESOURCES
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Key Concept Questions

• How are environmental resources classified?
• What effects do human activities have on natural
  resources

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Resources

• Earths resources are described as renewable or
  nonrenewable.
• Renewable resources are natural resources that
  can be replaced at the same rate at which they
  are consumed.
• A renewable resources supply is either so large
  or so constantly renewed that it will never be
  used up.

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• RENEWABLE RESOURCES
• Trees
• Water
• Air

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• Nonrenewable resources are resources that form at
  a rate that is much slower than the rate at which
  they are consumed.
• Most of our energy today comes from fossil fuels.
  
• Fossil fuels are nonrenewable energy resources
  that formed from the remains of organisms that
  lived long ago.

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• Fossil fuels such as coal, oil, and natural gas,
  are nonrenewable resources because it takes
  millions of years for them to form.
• We use fossil fuels at a rate that is faster than
  the rate at which they form. So, when these
  resources are gone, millions of years will pass
  before more have formed.

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How can people be sure that renewable resources
will be available for future generations?
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SUSTAINABLE USE

• a way of using natural resources at a rate that
  does not deplete them
• use of biological pest control instead of
  pesticides
• rotating animal grazing grounds
• planting trees after others have been cut down

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Sustainable 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

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• 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

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What effect do human activities have on natural
resources?

• Human activities affect the supply and the
  quality of renewable resources

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Land Resources

• space for cities and industry
• supplies raw materials
• soil for crops

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Soil Damage

• Fertile soil allows agriculture to supply the
  world with food.
• Fertile soil forms from rock that is broken down
  by weathering.
• Nutrients that make soil fertile come from the
  weathered rock as well as from bacteria, fungi
  and the remains of plants and animals.
• The processes that form just a few centimeters of
  fertile soil can take thousands of years.

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• The greatest threat to soil is soil erosion.
• Erosion is a process in which the materials of
  Earths surface are worn away by wind, gravity,
  or water.

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DESERTIFICATION

• In certain parts of the world with dry climates,
  a combination of farming, overgrazing, and
  drought has turned once productive areas into
  deserts

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• Sustainable agricultural practices can prevent
  erosion

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Terracing
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Crop Rotation
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Cover Crop
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Contour Plowing
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Ecosystem Disruption

• Ecosystem disruptions can result in loss of
  biodiversity, food supplies, potential cures for
  diseases, and the balance of ecosystems that
  supports all life on Earth.
• We cannot avoid disrupting ecosystems as we try
  to meet the needs of a growing human population.
• We can learn about how our actions affect the
  environment so that we can create ways to
  conserve it.

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• Over the last 50 years, about half of the worlds
  tropical rain forests have been cut down or
  burned for timber, pastureland, or farmland. This
  process of clearing forests is called
  deforestation.
• The problem with deforestation is that as the
  rain forests and other habitats disappear, so do
  their inhabitants.
• Habitat destruction and damage cause more
  extinction and loss of biodiversity than any
  other human activities do.

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• How We Can Help
• replant trees
• new tree varieties are being created to grow
  faster

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Ocean Resources

• food
• Problem
• over fishing stresses ecosystems
• How We Can Help
• limits on numbers of fish caught

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• AQUACULTURE
• Farming of aquatic ecosystems

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Air Resources

• Fossil fuel emissions affect the biosphere.

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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
• microscopic particles of ash and dust that can
  enter the nose, mouth, and lungs, causing health
  problems over a long term

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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

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• McDougall video Air Pollution

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• How We Can Help
• strict automobile emission standards
• technology to reduce emissions from smokestacks
  of factories

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• Water Resources
• drinking
• washing
• watering crops

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Water pollution affects ecosystems.

• Pollution can put entire freshwater ecosystems at
  risk.

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Water Pollution

• Water pollution can come from fertilizers and
  pesticides used in agriculture, livestock farms,
  industrial waste, oil runoff from roads, septic
  tanks, and unlined landfills.
• Pollution enters groundwater when polluted
  surface water percolates down through the soil.
• Landfills and leaking underground septic tanks
  are also major sources of groundwater pollution.

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• When pollutants run off land and into rivers,
  both aquatic habitats and public water sources
  may be contaminated.
• Fertilizers from farms, lawns, and golf courses
  can run off into a body of water, which increases
  the amount of nutrients in the water leading to
  an excessive growth of algae.
• Algal blooms can deplete the dissolved oxygen in
  a body of water. Fish and other organisms then
  suffocate in the oxygen-depleted water.

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Water Pollution
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• How We Can Help
• protect wetlands such as swamps they help
  purify through the water cycle
• conserve use
• cleaning water sewage treatment plants

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Key Concept Questions

• How are environmental resources classified?
• Renewable or nonrenewable
• What effects do human activities have on natural
  resources?
• Human activities affect the supply and the
  quality of renewable resources

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SECTION 3 BIODIVERSITY
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Key Concept Questions

• What is the value of biodiversity?
• What are the current threats to biodiversity?
• What is the goal of conservation biology?

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BIODIVERSITY

• Is the sum total of the genetically based variety
  of all organisms in the biosphere

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Biodiversity
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Species Diversity
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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

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• Ecosystem disruption decreases the number of
  Earths species.
• Biodiversity affects the stability of ecosystems
  and the sustainability of populations.
• Every species plays an important role in the
  cycling of energy and nutrients in an ecosystem.
  Each species either depends on or is depended on
  by at least one other species.

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• Indicator species provide a sign of an
  ecosystems health.
• Amphibians
• top predators

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• EXTINCTION
• occurs when a species disappears from all or part
  of its range
• ENDANGERED SPECIES
• a species whose population size is declining in a
  way that places it in danger of extinction

This baby Slender Loris is a member of the shy,
nocturnal primate species
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• As the population of an endangered species
  declines, the species loses genetic diversity-an
  effect that can make it even more vulnerable to
  extinction
• Once a species becomes extinct, will it ever
  reappear?
• NO

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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

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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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• Many forms of pollution can threaten
• biodiversity, but one of the most serious
• problems occurs when toxic compounds
• accumulate or build up in the tissues of
• organisms
• Ex) DDT cheap pesticide, long acting, and
  worked very well
• Problems nonbiodegradeable and not eliminated
  from animals bodies

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• One effect of DDT on eagles was to make their
  eggs too fragile to survive intact

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DDT
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BIOLOGICAL MAGNIFICATION (Biomagnification)(Bioa
ccumulation)

• concentrations of a harmful substance increase in
  organisms at higher trophic levels in a food
  chain or food web

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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.

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• Which food level is at the highest risk for
• biological magnification?
• Top-level carnivores

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Bioaccumulation
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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 environmentaland
  economic impact.

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Invasive Species
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Zebra Mussel Purple Loostrife
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• Invasive species often push out native species.
• Burmese python (Florida Everglades)

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• mice (Australia)

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• kudzu (southeastern United States)

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Conservation 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.
• the habitat in which the species lives must be
  protected
• other species are protected because they share
  the ecosystem

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Protecting 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

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• The National Park Service helps manage public
  lands.
• The park system includes over 390 areas, covering
  84 million acres.

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• There are several ways that people can help
  protect the environment.
• control population growth
• develop sustainable technology and practices
• protect and maintain ecosystems

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Visual Concept Conservation
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Key Concept Questions

• What is the value of biodiversity?
• Species of many kinds have provided us with
• Foods
• industrial products
• Medicines
• Painkillers
• Antibiotics
• heart drugs
• Antidepressants
• anticancer drugs

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Key Concept Questions

• What are the current threats to biodiversity?
• Habitat fragmentation
• invasive species
• endangered species
• What is the goal of conservation?
• protecting existing natural habitats.

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SECTION 4 CHARTING A COURSE FOR THE FUTURE
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Key Concept Question

• What are two types of global change of concern to
  biologists?

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• WHAT ARE TWO TYPES OF GLOBAL
• CHANGE OF CONCERN TO BIOLOGISTS?
• The thinning, or depletion, of the ozone layer
• Global warming
• Oxygen O2
• Ozone O3

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• OZONE LAYER
• between 20 and 50 kilometers above the Earths
  surface, the atmosphere contains a concentration
  of ozone gas
• Absorbs UV radiation before sunlight hits Earth

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Visual Concept Ozone and Ecosystems
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Ozone Hole Over Antarctica
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What happens if a person receives too much sun?

• Sunburn
• Cancer
• Damage eyes
• Decrease disease resistance
• Too much UV radiation can have a harmful
• effect on plants and phytoplankton in the
• oceans

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What is the cause of the holes in the ozone layer?

• CFCs chlorofluorocarbons they were chemicals
  used in aerosol cans as the propellant, coolant
  in refrigerators, freezers, and air conditioners

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• What would happen to the temperature of
• the atmosphere if the amount of
• greenhouse gases increased?
• The atmosphere would become warmer global
  warming

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• The greenhouse effect slows the release of energy
  from Earths atmosphere.
• sunlight penetrates Earths atmosphere
• energy is absorbed and reradiated as heat
• greenhouse gases absorb longer wavelengths
• Greenhouse gas molecules rereleaseinfrared
  radiation

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• Global warming refers to the trend of increasing
  global temperatures.

North Pole
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Air 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.

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• Scientists around the world are trying to make
  models of the effect of increasing global
  temperatures to predict what the future will be
  like

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Visual Concept Greenhouse Effect
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Visual Concept Global Warming
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Key Concept Question

• What are two types of global change of concern to
  biologists?
• Depletion of the ozone layer and Global Warming