1. CHAPTER 6 HUMANS 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 Earth’s
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 Earth’s other multicellular species*

10. Let’s 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 1800’s
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
Earth’s 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 resource’s 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 Earth’s 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 world’s 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 Insects Protists Other Animals Plants Bacteria Fungi
54.4%
4.2%
18%
3.4%
0.3%
19.7%

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 Earth’s 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 ecosystem’s health.
Amphibians
top predators

63. occurs when a species disappears from all or part of its range
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) (Bioaccumulation)
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.

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 environmental and 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 Earth’s 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 Earth’s 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

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?
CFC’s = 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. sunlight penetrates Earth’s atmosphere
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 gas molecules rerelease infrared radiation
methane (CH4)
water (H2O)
carbon dioxide (CO2)

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

100. 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.

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