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48.1 The nature of ecosystems
  • The biosphere, where all living things exist, consists of ecosystems.
  • In an ecosystem, organisms interact with one another and with the abiotic environment.
  • Trophic (feeding) relationships are essential to the workings of an ecosystem.
  • Autotrophs are self-feeders: photoautotrophs capture solar energy and produce organic nutrients. Heterotrophs, on the other hand, take in preformed organic nutrients.
  1. How does the hydrosphere (oceans and other waters of the world) moderate temperatures?
    Answer
  2. What are the three gases present in the atmosphere that are important to life and how are they important?
    Answer
  3. What happens to energy and materials (nutrients) within an ecosystem?
    Answer
  4. How do heterotrophs and autotrophs obtain food?
    Answer
  5. What is the importance of decomposers in an ecosystem?
    Answer
  6. True or false: All energy contained within an organism is acquired by another when it is consumed.
    Answer
Essential Study Partner Summaries of major points
  1. The earth
  2. The biotic community
  3. Autotrophs
  4. Heterotrophs
48.2 Energy flow
  • Solar energy enters biotic communities via photosynthesis, and as organic nutrients pass from one trophic level to another, heat is returned to the atmosphere.
  • Nutrients cycle within and between ecosystems in global biogeochemical cycles.
  1. A diagram that describes who eats whom within an ecosystem is called a ___________________.
    Answer
  2. What is a trophic level and what organisms are found in the first three trophic levels?
    Answer
  3. What is an ecological pyramid?
    Answer
Essential Study Partner Summaries of major points
  1. Ecosystems
  2. Food webs and ecological pyramids
  3. Trophic levels
  4. Ecological pyramids
Art Quizzes
48.3 Global biogeochemical cycles
  • Biogeochemical cycles are gaseous (carbon cycle, nitrogen cycle) or sedimentary (phosphorus cycle).
  • The addition of carbon dioxide (and other gases) to the atmosphere is associated with global warming.
  • The production of fertilizers from nitrogen gas is associated with acid deposition, photochemical smog, and temperature inversions.
  • Fertilizer also contains mined phosphate; fertilizer runoff is associated with water pollution.
  1. What are the parts of a biogeochemical cycle?
    Answer
  2. What are reservoirs of carbon?
    Answer
  3. What are greenhouse gases and what do they do?
    Answer
  4. What is the importance of nitrogen-fixing bacteria?
    Answer
  5. What effect can phosphate and nitrogen runoff from human activities have on aquatic communities?
    Answer
Essential Study Partner Summaries of major points
  1. Biogeochemical cycles
  2. The hydrologic cycle
  3. The carbon cycle
  4. Carbon dioxide and global warming
  5. The nitrogen cycle
  6. The phosphorus cycle
  7. Phosphorus and water pollution
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