Activities Key Terms Quizzes Art Chapter 44 Self-Quiz
Unit 6: Interaction with the Environment Ecosystems Review
  1. Ecosystems consist of a of organisms together with the environment in which they live. Ecosystems are open systems in which energy flow is , and in which materials and nutrients are .
     
     
  2. Food webs can be represented as energy with each step representing a level. Energy is lost as at each trophic level, and only about percent of the available energy is transferred between trophic levels, and producers are only about percent efficient in obtaining energy from the Sun through chlorophyll.
     
     
  3. Nutrients are cycled slowly through cycles or more rapidly through cycles . Human activity can upset the balance of materials through these cycles, resulting in .
     
     
  4. Sedimentary cycles are especially susceptible to excess and , resulting in blooms that lead to , the depletion of oxygen in aquatic ecosystems.
     
     
  5. Important pollutants in the atmospheric cycle include sulphur, which is released as when fuels are burned and can cause precipitation in ecosystems far away from the source of the pollution.
Activities Key Terms Quizzes Art Chapter 45 Self-Quiz
Unit 6: Interaction with the Environment Global Change Review
  1. Atmospheric nitrogen (N2) are converted to forms usable by living organisms by in a process called nitrogen . Some of the bacteria form mutualistic associations with plants called .
    • The nitrogen cycle in ecosystems has been affected through synthetic nitrification for . This leads to the decline of native plant species in North America and the increase of Old World species adapted to artifically high levels of nitrogen.
    • Excess nitrogen in ecosystems can lead to blooms with an in productivity but a in diversity.
     
     
  2. The carbon cycle has been affected through burning and forests. The increase in atmospheric CO2 levels can affect species compositions in natural communities and also cause global through the effect . This will have large effects on our terrestrial biomes, which are heavily affected by .
     
     
  3. Another important cycle is , which cycles through ecosystems through , , and . Like all materials, this resource is recycled. All organisms need water, and all of the water we use has been recycled countless times.
     
     
  4. Human activity can introduce synthetic chemicals which can alter the biosphere in unexpected ways. An example is refrigerants made from (chlorofluorocarbons), which may have caused the depletion of the layer.
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