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CHAPTER 6 HUMANS IN THE BIOSPHERE

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Title: CHAPTER 6 HUMANS IN THE BIOSPHERE


1
CHAPTER 6HUMANS IN THE BIOSPHERE
2
SECTION 1 A CHANGING LANDSCAPE
3
Key Concept Question
  • What types of human activities can affect the
    biosphere?

4
  • 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

5
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.

6
  • 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.

7
Visual Concept Human Population
8
What types of human activities can affect the
biosphere?
  • hunting and gathering
  • agriculture
  • industry
  • urban development

9
According to a recent study, human activity uses
as much energy as all of Earths other
multicellular species
10
  • Lets think about how humans have changed
    throughout history.

11
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

12
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

13
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

14
Results of the Industrial Revolution during 1800s
  • reliance on fossil fuels
  • increased use of mineral resources
  • large-scale production of manufactured goods

15
Suburban sprawl
  • The spread of suburban communities across America

16
  • Problems
  • large amounts of waste that needs to be disposed
    of
  • consumes farmland
  • consumes natural habitats
  • places stress on native plants and animals

17
Key Concept Question
  • What types of human activities can affect the
    biosphere?
  • hunting and gathering
  • agriculture
  • industry
  • urban development

18
SECTION 2 RENEWABLE AND NONRENEWABLE RESOURCES
19
Key Concept Questions
  • How are environmental resources classified?
  • What effects do human activities have on natural
    resources

20
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.

21
  • RENEWABLE RESOURCES
  • Trees
  • Water
  • Air

22
  • 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.

23
  • 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.

24
How can people be sure that renewable resources
will be available for future generations?
25
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

26
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

27
  • 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

28
What effect do human activities have on natural
resources?
  • Human activities affect the supply and the
    quality of renewable resources

29
Land Resources
  • space for cities and industry
  • supplies raw materials
  • soil for crops

30
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.

31
  • 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.

32
DESERTIFICATION
  • In certain parts of the world with dry climates,
    a combination of farming, overgrazing, and
    drought has turned once productive areas into
    deserts

33
  • Sustainable agricultural practices can prevent
    erosion

34
Terracing
35
Crop Rotation
36
Cover Crop
37
Contour Plowing
38
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.

39
  • 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.

40
  • How We Can Help
  • replant trees
  • new tree varieties are being created to grow
    faster

41
Ocean Resources
  • food
  • Problem
  • over fishing stresses ecosystems
  • How We Can Help
  • limits on numbers of fish caught

42
  • AQUACULTURE
  • Farming of aquatic ecosystems

43
Air Resources
  • Fossil fuel emissions affect the biosphere.

44
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

45
  • 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

46
  • McDougall video Air Pollution

47
  • How We Can Help
  • strict automobile emission standards
  • technology to reduce emissions from smokestacks
    of factories

48
  • Water Resources
  • drinking
  • washing
  • watering crops

49
Water pollution affects ecosystems.
  • Pollution can put entire freshwater ecosystems at
    risk.

50
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.

51
  • 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.

52
Water Pollution
53
  • How We Can Help
  • protect wetlands such as swamps they help
    purify through the water cycle
  • conserve use
  • cleaning water sewage treatment plants

54
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

55
SECTION 3 BIODIVERSITY
56
Key Concept Questions
  • What is the value of biodiversity?
  • What are the current threats to biodiversity?
  • What is the goal of conservation biology?

57
BIODIVERSITY
  • Is the sum total of the genetically based variety
    of all organisms in the biosphere

58
Biodiversity
59
Species Diversity
60
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

61
  • 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.

62
  • Indicator species provide a sign of an
    ecosystems health.
  • Amphibians
  • top predators

63
  • 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
64
  • 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

65
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

66
  • Habitat corridors are a solution to the problem.
  • corridors can be road overpasses or underpasses
  • allow species to move between different areas of
    habitat

67
  • 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

68
  • One effect of DDT on eagles was to make their
    eggs too fragile to survive intact

69
DDT
70
BIOLOGICAL MAGNIFICATION (Biomagnification)(Bioa
ccumulation)
  • concentrations of a harmful substance increase in
    organisms at higher trophic levels in a food
    chain or food web

71
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.

72
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73
  • Which food level is at the highest risk for
  • biological magnification?
  • Top-level carnivores

74
Bioaccumulation
75
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.

76
Invasive Species
77
Zebra Mussel Purple Loostrife
78
  • Invasive species often push out native species.
  • Burmese python (Florida Everglades)

79
  • mice (Australia)

80
  • kudzu (southeastern United States)

81
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

82
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

83
  • The National Park Service helps manage public
    lands.
  • The park system includes over 390 areas, covering
    84 million acres.

84
  • There are several ways that people can help
    protect the environment.
  • control population growth
  • develop sustainable technology and practices
  • protect and maintain ecosystems

85
Visual Concept Conservation
86
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

87
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.

88
SECTION 4 CHARTING A COURSE FOR THE FUTURE
89
Key Concept Question
  • What are two types of global change of concern to
    biologists?

90
  • 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

91
  • 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

92
Visual Concept Ozone and Ecosystems
93
Ozone Hole Over Antarctica
94
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95
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

96
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

97
  • What would happen to the temperature of
  • the atmosphere if the amount of
  • greenhouse gases increased?
  • The atmosphere would become warmer global
    warming

98
  • 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

99
  • Global warming refers to the trend of increasing
    global temperatures.

North Pole
100
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.

101
  • Scientists around the world are trying to make
    models of the effect of increasing global
    temperatures to predict what the future will be
    like

102
Visual Concept Greenhouse Effect
103
Visual Concept Global Warming
104
Key Concept Question
  • What are two types of global change of concern to
    biologists?
  • Depletion of the ozone layer and Global Warming
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