Humans and the Environment - PowerPoint

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					        Topic 2E
Humans and the Environment

While, all living things have impacts on the
environment, humans have a larger impact than
other organisms. Some reasons for the greater
impact are:
• Pursuit of resources – food, coal, wood
•Generation of wastes and pollution –
radioactivity, garbage etc
• These activities can upset ecosystem
  processes
• Prevent soil production
• Interrupt natural food pyramids and energy
  flow
Changes brought about by humans can cause
  harm to populations of other organisms.
Pollution
Use of resources creates wastes, changing
  composition of air, soil and water.

Significant problems from pollution of the air
  include:


            Ozone Depletion
            Global Warming
            Acid Rain
              Ozone Depletion

Ozone in the stratosphere keeps 95-99% of
the sun’s ultraviolet radiation from striking
the earth
In 1974, it was reported that ozone in the
stratosphere was declining because of man-
made compound known as
ChloroFloroCarbon’s (CFC’s)
    Used in styrofoam and refrigerants.
The Ozone Hole over the Antarctic
allows through UV radiation that
can cause
•Genetic damage
•Eye damage
•Decrease in marine and amphibian
populations
           Global Warming
Carbon Dioxide is a product of burning fossil
 fuels made up of carbon.
Carbon Dioxide is a greenhouse gas. CO2
 traps heat near the Earth’s surface.
 (Greenhouse effect)
The Greenhouse effect will lead to global
 warming which could cause


           Climate Change
How Will Climate Change Influence
Other Organisms?
• Creates barriers to migration from
  one climate to the other
• Environment could change faster than
  pace of evolutionary change in
  organisms
• Could lead to massive extinction of
  species
              Acid Rain
Burning of coal produces sulfur dioxide
 and nitrous dioxide which react with
 water in the atmosphere to create
 H2SO4 and HNO3

          Sulfuric Acid
          Nitric Acid
   These acids combine with rain to
   increase acidity (lower pH)
• Impacts of Acid Rain on the
 Environment
   - Acidification of Lakes
        Kills aquatic insects
        Kills Fish
   - Wash nutrients from soils
        Harms plants

  Impacts the food chain
            Water Pollution

• Lakes, rivers and groundwater can be
 polluted from activities within a
 watershed. (The land over which rain
 water drains to fill bodies of water)
  – Examples: Runoff from farms, inappropriate
    disposal of household chemicals, discharge
    from manufacturing, spills etc.
PCB’s in the Hudson River
• PCB’s are an oily liquid that were used in
  electrical equipment to prevent
  overheating and fires.
• PCB’s build up in the tissues of animals
  because they do not like to be in water,
  rather they like to be in fatty substances.
• PCB’s built up in bodies of fish and then in
  the bodies of animals that eat fish
 The storing of a chemical in living things is
 called:
            Bioaccumulation
Other Examples of Bioaccumulation
• DDT – Build up of insecticides in birds
  which prevented reproduction.
• Mercury – Build of toxic metal which
  causes neurological problems in animals.

Bioaccumulation influences the entire food
  chain. The top predator usually has the
  highest quantity of chemical.
All of these pollution related
problems influence the ecosystem
and can result in habitat loss for
organisms.
 Habitat is the place where a species can meet all of
 its life function needs:
 Where it can get the food that matches its designs,
 water, appropriate shelter from cold and predation
 and reproduce to continue its species.
Any impact that influences an animals ability
  to meet habitat needs could cause a
  decline in population of a species
In addition to air and water pollution, what
  human activities can lead to habitat
  destruction?
  – Cutting down of forests
  – Building Cities that prevent movement of
    species
  – Diversion of water ways

				
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