Biology 10 - Introduction to General Biology
Ecosystems
     It is a common viewpoint that life is static. Nothing is further from the truth. Ecosystem ecologists attempt to capture the "big picture" of life on earth.  More than 99% of all life forms depend directly or indirectly on the input of solar energy into the ecosystems on our planet. The bulk of the chemical elements that make up organisms enter and leave individuals at a rapid pace. The views of ecosystem ecologists have had a major effect on biology over the last fifty years. Your journey into ecosystem ecology illustrates the principles of how energy and chemical elements flow between biotic and abiotic reservoirs.
Life depends on solar energy
    1. Understand the role of chemical cycling and energy flow in ecosystems. What is the difference between them?
    2. Is it appropriate to say that an organism is essentially a temporary "holding" place for energy and materials within the ecosystem?
    3. Grasp the idea of trophic levels in the food chain. Be able to define producers, consumers (primary, secondary etc.), decomposers (detrivores) and to give examples of each.
    4. Sketch a food chain and label its components in the correct order.
    5. Which are the TWO most important components of a food chain? (hint: without these two components the chain would cease to work).
    6. What is an autotroph? A heterotroph?
    7. Why are detrivores and decomposers so important. Could an ecosystem function without them?
    8. Define phytoplankton vs zooplankton. What is their role in aquatic food chains? Recall from lecture that food chains in aquatic systems typically are much longer compared to terrestrial systems.
    9. Understand the connection between food chains and food webs. Which one gives a better representation of reality?
    10. Be able to explain the flow of energy through a food chain and how it is related to the concept of biomass, primary productivity and the energy pyramid.
    11. It is essential that you understand the "10% Rule" and the concept of how energy is lost as it flows between trophic levels. How is energy lost? In addition, you should be able to outline the flow of energy between trophic levels and estimate the amount being transferred.
    12. Be able to discuss how our knowledge of the energy pyramid gives us a better understanding of how to obtain food for the growing human population. What kind of food sources are likely to dominate in the future? Explain why?
    13. Chemical elements cycle continuously between the biotic and abiotic reservoirs. In which of these reservoirs do you think the elements spend most of their time?
    14. Describe how water molecules cycle in the biosphere. Use this cyucle to illustrate the concept of flow. Is the water cycle important for life on the planet?
    15. Explain how the element carbon cycles through biotic and abiotic reservoirs in different chemical forms.
    16. Is the element carbon (C) destroyed in the process of cycling? What happens to the element as it cycles between the different reservoirs?
    17. Understand the role of organisms in the carbon cycle via the processes of photosynthesis and cellular respiration. What happens to the element carbon in these biological processes? Organic molecules are mostly composed of carbon.
    18. Where can one find the element nitrogen (N) in living organisms (e.g. in your own cells)?
    19. Understand how the element nitrogen cycles between different chemical forms. The nitrogen fixing bacteria are the portal between atmospheric nitrogen (N2) and nitrogen available to plants. Are these bacteria important for life on Earth? Why or why not?
    20. Another example of cycling: phosphorus. Understand that each element cycles through biotic and abiotic reservoirs.
    21. The elements cycle between different reservoirs. They appear to rarely be destroyed even though the take on different chemical "shapes" (part of different kinds of molecules). Where did the elements form in the first place? (refresh your astronomy knowledge or look at your notes).
    22. Review: What are the main differences between the flow of energy and the cycling of the elements? Are there any similarities?


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Page created by: Peter Svensson
Updated: May 16, 2011