Option G:  Ecology and Conservation

A.S. Obj. G.1 Ecology of Species (3h)
G.1.1 2
  • Outline the factors that affect the distribution of plant species including temperature, water, light, soil pH, salinity and mineral nutrients.
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    G.1.2 3 Explain the factors that affect the distribution of animal species including temperature, water, breeding sites, food supply and territory.
    G.1.3 3
    Deduce the significance of the difference between two sets of data using calculated values for t and the appropriate tables.
    The t-test can be used to compare two sets of data and measure the amount of overlap.  Students will not be expected to calculate values of t.
     
    G.1.4 3
  • Explain what is meant by the niche concept, including an organism's spatial habitat, it feeding activities and its interactions with other organisms.
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    G.1.5 3 Explain the principle of competitive exclusion.
        G.2 Ecology of Communities (5h)
    G.2.1 3
    Explain the following interactions between species, giving two examples of each:  competition, herbivory, predation, parasitism and mutualism.
    Mutualism is where two members of different species benefit and neither suffers.  Examples include rumen bacteria/protozoa, lichens and Chlorella/Chlorohydra.
    G.2.2 1
  • Define gross production, net production and biomass.
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    G.2.3 2
    Calculate values for gross production, net production and biomass from given data.
    Gross production - respiration = net production
    G.2.4 3
  • Discuss the difficulties of classifying organisms into trophic levels.
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    G.2.5 3 Explain the small biomass and low numbers of organisms in higher trophic levels.
    G.2.6 3
    Construct a pyramid of energy given appropriate information.
    The lowest bar of the pyramid of energy represents gross primary productivity, the next bar represents the energy ingested as food by primary consumers, and so on.  The units are energy per unit area per unit time.
    G.2.7 2
  • Describe ecological succession using one example.
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    G.2.8 3
    Explain the effects of living organisms on the abiotic environment with reference to the changes occurring during ecological succession to climax communities.
    Include soil development, accumulation of minerals and reduced erosion.
        G.3 Biodiversity and Conservation (7h)
    G.3.1 3
  • Discuss reasons for the conservation of biodiversity using rainforests as an example.  Reasons should include ethical, ecological, economic and aesthetic arguments.
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    G.3.2 2
    Outline the factors that caused the extinction of one named animal and one named plant species.
    Choose examples from recent historical time.
    G.3.3 2
  • Outline the use of the Simpson diversity index.
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            N (N-1)
    D = S n(n-1)
     
    • D = diversity index
    N = total number of organisms of all species found
    n = number of individuals of a particular species
    The Simpson diversity index is a measure of species richness.  A high value of D suggests a stable and ancient site and a low D value could suggest pollution, recent colonization or agricultural management.  The index is normally used in studies of vegetation but can also be applied to comparisons of animal (or even all species) diversity.
    G.3.4 3 Explain the use of biotic indices and indicator species in monitoring environmental change.
    G.3.5 2 Outline the damage caused to marine ecosystems by the overexploitation of fish.
    G.3.6 3 Discuss international measures that would promote the conservation of fish.
    G.3.7 3
  • Discuss the advantages of in situ conservation of endangered species (terrestrial and aquatic nature reserves).
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    G.3.8 2
    Outline the management of nature reserves.
    Include control of alien species, restoration of degraded areas, promotion of the recovery of threatened species and control of human exploitation.
    G.3.9 2
  • Outline the use of ex situ conservation measures including captive breeding of animals, botanic gardens and seed banks.
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    G.3.10 3
    Discuss the role of international agencies and conservation measures including CITES and WWF.
    CITES - Convention on International Trade in Endangered Species
    WWF - World Wildlife Fund
        G.4  The Nitrogen Cycle (4h)
    G.4.1 1 State that all chemical element occuring in organisms are part of biogeochemical cycles and that these cycles involve water, land and the atmosphere.
    G.4.2 3 Explain that all biogeochemical cycles summarize the movement of elements through the biological components of ecosystems (food chains) to form complex organic molecules, and subsequently simpler inorganic forms which can be used again.
    G.4.3 3 Explain that chemoautotrophs can oxidize inorganic substances as a direct energy source to synthesize ATP.
    G.4.4 1 State that chemoautotrophy is found only among bacteria.
    G.4.5 1
    Draw a diagram of a nitrogen cycle.
    Include the process of nitrogen fixation (free-living, symbiotic and industrial), denitrification, nitrification, feeding, excretion, root absorption, and putrefaction (ammonification).
    G.4.6 2 Outline the roles of Rhizobium, Azotobacter, Nitrosomonas, Nitrobacter and Pseudomonas denitrificans in the nitrogen cycle.
    G.4.7 2 Describe the conditions that favour denitrification and nitrificaiton.
    G.4.8 3 Discuss the actions taken by farmers/gardeners to increase the nitrogen fertility of the soil including fertilizers, plowing/digging and crop rotation (use of legumes).
        G.5 Impacts of Humans on Ecosystems (3h)
    G.5.1 2 Describe the role of atmospheric ozone in absorbing ultra violet (UV) radiaiton.
    G.5.2 2 Outline the effects of UV radiation on living tissues and biological productivity.
    G.5.3 2 Outline the chemical effect of chlorine on the ozone layer.
    G.5.4 3 Discuss methods of reducing the manufacture and release of ozone-depleting substances including recycling refrigerants, reducing production of gas-blown plastics and using CFC-free propellants.
    G.5.5 2
    Outline the consequences of releasing raw sewage and nitrate fertilizer into rivers.
    Include pathogens in bathing or drinking water, eutrophication, algal blooms, deoxygenation, increase in biochemical oxygen demand (BOD) and subsequent recovery.  Names of specific organisms are not expected.
    G.5.6 2 Outline the origin, formation and biological consequences of acid precipitation on plants and animals.
    G.5.7 1 State that biomass can be used as a source of fuels such as methane and ethanol.
    G.5.8 3 Explain the principles involved in the generation of methane from biomass, including the conditions needed, organisms involved and the basic chemical reactions that occur.