Ch.6 Humans in the Biosphere

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Ch.6 Humans in the Biosphere
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Natural Ecosystems Processes

• Natural systems have been upset
• humans influence other individuals, other
  species, and the nonliving world
• Humans in turn are also influenced by them.

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Natural Ecosystems Processes

• Some Natural Ecosystem Processes which affect
  humans
• 1.  maintenance of atmospheric quality
• 2.  generation of soils
• 3.  control of the water cycle
• 4.  removal of wastes
• 5.  energy flow
• 6.  recycling of nutrients
•   Humans have changed many of these ecosystem
  processes --
  frequently in a detrimental way.

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Human Population Growth

• The total population of humans has risen at a
  rapid rate
• Due to the removal of natural checks on the
  population, such as disease.
• The earth has finite resources
• increasing human population and consumption
  places severe stress on natural processes that
  renew some resources and deplete those resources
  which can not be renewed.

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HUMAN POPULATION GROWTH GRAPH

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A Lesson on Overpopulation

• Kaibab national forest - Arizona - deer
• 1906 - stable population of 4,000 deer - bounty
  was placed on their predators
• 1906-23 deer population swells and overgrazing
  begins - over 6,000 predators killed
• 1924-25 of the 100,000 deer present -- over 75
  die - chiefly of starvation malnutrition
• 1939 - fewer than 10,000 deer remained
• Destruction of natural enemies is not always
  good for a species
• it can lead to its extinction or near extinction
• (Will this also happen to Homo sapiens?)

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Specific Human Influences on Ecosystem Factors

• 1. Increasing numbers
• -- results from an increased human life span--
  health advances largely led to this
• 2. Food shortages and inadequate nutrition lead
  to starvation and malnutrition
• -- population growth is outpacing food
  production in many world regions
• starvation body lacks sufficient calories for
  maintenance
• malnutrition diet lacks specific substances
  needed by the body

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Specific Human Influences on Ecosystem Factors

• 3. Soil much loss of fertile topsoil due to
  erosion and poor management
• -- the use of biocides has contaminated the soil
  (no prior assessment was taken of their
  environmental impact)
• -- some causes of topsoil loss
• - cutting forests, farming dry grasslands,
  damming rivers, draining wetlands, etc.
• -- much valuable farmland has been lost due to
  increasing urbanization suburbanization

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Specific Human Influences on Ecosystem Factors

• 4. Water
• - much waste occurs -- cutting forests has led
  to increased, uncontrolled runoff
• -- water pollution leaves water unfit for use
  and the living things remaining in it unfit for
  consumption  
• - (typical water pollutants include
  phosphates, heavy metals, and PCB's)
• biomagnification increase in the concentration
  of a substance (poison) in living tissue as you
  move up the food chain

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Biomagnification
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Specific Human Influences on Ecosystem Factors

• 5. Wildlife much destruction and damage has been
  done to many species  (hunting, fishing, etc.)
• ex. passenger pigeon, dodo, great auk, bison,
  carolina parakeet

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Specific Human Influences on Ecosystem Factors

• 6. Fossil Fuels are becoming rapidly
  depleted/add to air pollution problems
• - The search and demand for additional energy
  resources also impact ecosystems in a negative
  way. 
• - Industrialization has brought an increased
  demand for and use of energy.
• 7.  Nuclear fuels --- environmental dangers exist
  in reference to obtaining, using, and storing the
  wastes from these fuels

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Specific Human Influences on Ecosystem Factors

• 8. Air becoming increasingly polluted
• a.)  Greenhouse effect
• - adding carbon dioxide to the earth's
  atmosphere may be increasing its temperature
• - holds in the earth's heat radiation

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Specific Human Influences on Ecosystem Factors

• b.)  Acid Rain
• -- sulfur dioxide (also nitrogen oxides) from
  coal burning sources rain ACID RAIN
• -- Acid rain kills aquatic life, crumbles
  buildings, and has many other effects, etc.

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Map Showing the relative pH of U.S. Acid
Precipitation in 1998 (below)
                                                  
                                                  
             
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Specific Human Influences on Ecosystem Factors

• c.) Ozone Depletion
• -- CFC pollution from refrigerants and plastics
  are destroying our stratospheric ozone layer
• - this layer shields us from incoming
  ultraviolet radiation
• - increased skin cancers and cataracts are
  resulting from this destruction

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Specific Human Influences on Ecosystem Factors

• 9. Living space/available land is greatly
  decreasing as a result of increasing population
• -- creates increasing stress on individual
  humans
• -- we are also taking up living space and
  resources needed by other organisms
• 10. Forests are becoming increasingly depleted
  as a result of timber needs the need for more
  agricultural land
• -- the direct harvesting of timber has destroyed
  many forests
• -- this destruction also impacts land use and
  atmospheric quality

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Specific Human Influences on Ecosystem Factors

• 11. Affluent human lifestyles have led to waste
  disposal problems. (solid, chemical, nuclear) 
• 12. Insects our chief competitors for food
• -- we have destroyed many beneficialinsects and
  many enemies of harmful insects with insecticides
  
• 13.  Land use (includes increasing urbanization
  and the cultivation of marginal lands)
• -- this decreases the space and resources
  available to other species
• 14.  Pollution -- this changes the chemical
  composition of the soil, air, and water

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Factors Which Influence Environmental Quality

• 1.  Population growth and distribution
• 2.  Capacity of technology to solve problems
• 3.  Economic, political, ethical, and cultural
  views

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Factors Which Influence Environmental Quality

• Some examples   
• a.)  Wealthy people in the developed world tend
  to have fewer children.
• b.)  Some countries like China have laws
  concerning the number of children a couple may
  have without penalty.
• c.)  In some countries such as many in Latin
  America where the Catholic Church is a dominant
  institution, families tend to be larger as birth
  control violates church law.
• d.)  In some poor cultures in third world
  countries, having many children is seen as a
  means of having economic security in old age.

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How to deal with environmental degradation?

• a.)  Species Preservation
• -- efforts to sustain endangered species
• - habitat protection (wildlife refuges,
  national parks)
• - wildlife management (game laws and
  fisheries)
• -- Animals which were once endangered but are
  presently successfully reproducing and increasing
  their numbers are the bisons, gray wolves and
  egrets.
• -- Endangered animals which are currently
  responding to conservation efforts and beginning
  to make a comeback are the whooping crane, bald
  eagle, and peregrine falcon.
• The future of many species remains in doubt.
• Human activities that degrade ecosystems result
  in a loss of diversity in the living and
  nonliving environment.  These activities are
  threatening current global stability.

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How to deal with environmental degradation?

• b.) Ways to Reduce Air Pollution
• 1. Use fuels which contain less pollutant, such
  as low sulfur coal and oil.2. Utilize industrial
  or energy producing processes which minimize the
  creation of pollutants.3. Remove pollutants by
  using such devices as afterburners or catalytic
  converters before they enter the air.4. Design
  new products which meet basic needs without
  generating pollution.
• There are laws which regulate and guide the
  use of natural habitats.

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How to deal with environmental degradation?

• c.)  SEQR A New York State law designed to
  provide the opportunity for citizen review and
  comment of the environmental impact of any
  proposed development that has been determined to
  have significant impact on the environment.

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Individual and Societal Choices that Contribute
to Improving the Environment

• 1.   Through a greater awareness and application
  of ecological principles, each individual can
  help to assure that there will be suitable
  environments for succeeding generations on our
  planet.
• 2.  Individuals in society must decide on
  proposals which involve the introduction of new
  technologies. These decisions must assess
  environmental risks, costs, benefits, and
  trade-offs.