• Human Impacts on the Environment

  Based on Mader, Sylvia S. 1996. Biology - 5th Ed. WCB

  and

  Cox, G.W. 1997. Conservation Biology - 2nd ed. WCB

  and

  Levine, J.S. and K.R. Miller. 1994. Biology: Discovering Life. D.C. Heath

Biomagnification

Reading: Chapter 7 in Levine and Miller

Chapter 22 in Cox

Thesis: Human intervention has altered ecosystems, sometimes in unexpected ways (biomagnification)

1. Causes of Environmental Impacts:

   Overview at this point, details later.

   1. Human Population Growth
   2. 1. Exponential in nature
      2. From 130 million to 5.4 billion in 2,000 years
      3. May level off at 10-15 billion by 2050
   3. Industrialization
   4. 1. Greater demands on ecosystems
      2. Supports larger population
      3. Concentrates toxic materials
   5. Economic growth
      1. 1 baby born in US has same economic impact as 200 born in undeveloped countries.
   6. Agriculture
   7. 1. Necessary for human civilizations
      2. Limited amount of arable land

       

2. Current Environmental Problems
3. 1. Water Pollution
   2. 1. Industrial pollution
      2. Surface pollution
      3. Groundwater contamination
      4. Residential Sewage
   3. Air Pollution
   4. 1. Smog
      2. Acid Rain
      3. Ozone Depletion
      4. Global Warming
   5. Loss of Diversity
4. Problems caused by large-scale Agriculture
5. 1. Loss of Diversity
   2. Fertilizers and Eutrophication
   3. Pesticides
   4. Irrigation
   5. Soil Erosion
   6. Energy Use
6. Bioaccumulation & Biomagnification
7. 1. bioaccumulation: increase in concentration of a pollutant from the environment to the first organism in a food chain
   2. Biomagnification: increase in concentration of a pollutant from one link in a food chain to another
   3. pollutant must be:
   4. 1. long-lived
      2. mobile
      3. soluble in fats
      4. 1. if soluble in water they will be excreted
      5. biologically active
      6.  
   5. classic example: DDT
   6. 1. chlorinated hydrocarbon
      2. exhibits qualities shown above
      3. 1. half life 10-15 years
      4. low human toxicity
      5. heavily sprayed to combat
      6. 1. mosquitoes in Burma
         2. elm bark beetle
         3. Japanese beetle
         4. forest pests
      7. noticeable kill of fish, birds, mammals with above sprayings
      8. Rachel Carson - Silent Spring (1962)
   7. case study: Long Island Estuary (Figure 22.1 in Cox)
   8. 1. water® zooplankton: 800x
      2. zooplankton ® fish #1: 31x
      3. fish #1 ® fish #2: 1.7x
      4. fish #2 ® gull: 4.8x
      5. overall: 202,368x
   9. sub-lethal effects:
   10. 1. shell-thinning in birds
       2. 1. bird eating raptors
          2. fish-eating raptors
          3. fish-eating water birds
          4. carrion feeders
          5. shells are too thin to brood
          6. mechanisms not fully understood
          7. many populations have recovered
          8. 1. migratory birds may be exposed to pesticides in other countries
       3. effects on sex ratios in some species of birds
       4. 1. males "feminized"
   11. biomagnification also known for heavy metals and other substances
   12. 1. PCB’s
       2. PAH’s
       3. mercury, copper, cadmium, chromium, lead, nickel, zinc
       4. cyanide (used in leaching gold)
       5. TBT - tributyltin
       6. selenium
   13. modern pesticides
   14. 1. carbamates and organophosphates
       2. more toxic
       3. shorter-lived
       4. resistance
       5. important tools against disease
       6. IPM
8. Other pollutants:
9. 1. plastics
   2. radioisotopes
   3. 1. may be toxic and radioactive!
   4. oil
10. Regulations:
11. 1. Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA)
    2. 1. 1947
       2. requires registration of pesticides for specific uses
    3. Federal Environmental Pesticide Act
    4. 1. 1972
       2. controls use, release of pesticides
    5. London Dumping Convention
    6. 1. 1972
       2. ratified by 64 countries
       3. bans deliberate discharge of various toxic or other wastes
    7. International Convention for the Prevention of Pollution from Ships (MARPOL)
    8. 1. 1988
       2. prohibits dumping of plastics at sea
       3. ratified by 40 countries
12. Interactions between organisms:

13. 	Effect of Interaction On:
    Type of Interaction	Species 1	Species 2
    Competition	(-)	(-)
    Predation	Predator (+)	Prey (-)
    Parasitism	Parasite (+)	Host (-)
    Herbivory	Herbivore (+)	Plant (-)
    Detritivory	Detritivore (+)	Detritus (0)
    Commensalism	(+)	(0)
    Mutualism	(+)	(+)

    Table 1. Types of species interactions

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