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12.4: Review and Additional Resources

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    Arctic Wildlife Refuge
    Figure \(\PageIndex{1}\)

    Review and assess your learning. Start with the "Important Terms and Concepts" to ensure you know the terminology related to the topic of the chapter and concepts discussed. Move on to the "Review Questions" to answer critical thinking questions about concepts and processes discussed in the chapter. Finally, test your overall understanding by taking the "Self-assessment quiz".

    Important Terms and Concepts
    • Biogeography
      the study of the geographical patterns of plant and animal species
    • Ecology
      the study of the interactions among organisms
    • ecosystem
      a functioning entity of all the organisms in a biological system generally in equilibrium with the inputs and outputs of energy and materials in a particular environment
    • habitat
       the natural environment in which an organism lives
    • niche
      the function or occupation, of a life-form within a community. An organism's niche incorporates the physical (habitat), chemical, and biological factors that maintains the health and vitality of the organism.
    • photosynthesis
      the process of converting solar energy, water, and carbon dioxide into carbohydrates and oxygen
    • transpiration
      the loss of water from plant leaves
    • respiration
      the process of "burning" stored chemical energy, basically through oxidation, for maintaining plant metabolism
    • net biomass productivity
      the difference between gross productivity (production of plant material by photosynthesis) and respiration
    • trophic level
      an organism's position in a food chain
    • primary producer
      the bottom of the food chain; They convert solar energy into organic energy.
    • decomposer
      make use of energy stored in already dead plant and animal tissues
    • food chain
       the sequence of consumption and energy transfer through the environment
    • First law of thermodynamics
       energy cannot be created or destroyed
    • Second law of thermodynamics
      whenever energy is transformed, there is a loss energy through the release of heat
    • food web
      illustrates energy transfer between trophic levels
    • plant succession
      evolution of natural vegetation of a particular location
    • open forest
      lack of light for understory growth allows you to see into for some distance
    • closed forest
      canopy density is low, more light filters to the surface creating a thick ground cover; nearly impossible to see more than a few meters into it
    Review Questions \(\PageIndex{1}\)

    How do plants and animals differ in their ability to occupy habitats?


    The effectiveness of habitat occupation depends in part on the means of transportation. Animals must use their own locomotion, while plants disperse by wind, running water, ocean currents, and animals. Thus, climate and topographic barriers are more of an impediment to animals than plants. For either, continental drift poses a significant barrier to diffusion. The separation of continents has isolated plants and animals in the past thus preventing their complete occupation of a suitable habitat.

    What is photosynthesis, respiration, and transpiration?


    Photosynthesis is the process where by green plants convert carbon dioxide and energy into oxygen and stored carbohydrates. Respiration is the burning of stored chemical energy. Transpiration is the loss of water through the stomata of plant leaves.

    What is the difference between a habitat and niche?


    A habitat is the specific, physical location of an organism. Habitats can be identified at different spatial scales. A niche is the function or occupation, of a life-form within a community. An organism's niche incorporates the physical (habitat), chemical, and biological factors that maintains the health and vitality of the organism. An organism's interaction with the abiotic factors of its environment (heat and moisture) defines its niche.

    Which biome has the largest annual amount of net primary production?


    The tropical rain forest has the largest net primary production of all biomes.

    How do plants adapt to extreme aridity?


    Plants have adapted to dry conditions by evolving deep roots to extract water held deep beneath the surface. Some plants have extensive near surface root systems to catch infiltrating water, or thick fleshy leaves. Others have thick bark and or short waxy leaves to reduce transpiration. Plants go dormant during dry periods, drop their leaves, or have no leaves at all. They instead have thick moisture retentive, photosynthetic skin.

    Describe the concpet of "plant succession".


    Is the evolutionary process that tends toward a stable, diverse plant community (climax community). Each community prepares the environment for that which succeeds it.

    What are the limiting factors to growth in the low latitudes? High Latitudes?


    The limiting factor to growth in low latitudes is moisture. The limiting factor to growth in high latitudes is energy (solar radiation).

    Explain what a food chain is. Your answer must include the concepts of trophic level, primary producer, consumer and decomposer.


    A food chain is the sequence of consumption and energy transfer through an ecosystem. A food chain consists consists of different trophic levels which are the position of an organism in a food chain. At the base is the primary producers that convert solar energy into organic energy. Above the producers are the consumers that ingest live plants (primary consumer) or prey on other consumers (secondary consumer). Decomposers such as, bacteria, molds, and fungi make use of energy stored in already dead plant and animal tissues.

    How do plant communities affect the local environment in which they are found?


    Plant communities affect soil type when organic material decomposes into the soil altering soil moisture retention, infiltration capacity, soil structure and soil chemistry. Trees shade the forest floor, reducing incident solar radiation and lowering temperatures of both the soil and the air. Reduced incident light decreases evaporation keeping soils moister beneath the forest canopy. These impacts affect animal habitats and the diversity of animal species which are associated with these plant communities.

    What is net biomass productivity and determines it? What types of environments produce high and low amounts of biomass productivity?


    Net biomass productivity is the difference between gross productivity (production of plant material by photosynthesis) and respiration. Net productivity is closely related to a number of environmental factors like climate, soils, and available nutrients. Net biomass production will be highest where there is an ample supply of moisture to meet the needs of plants. Biomass productivity is also high where soils are rich in nutrients and have a positive soil moisture balance. Forest, especially tropical forest have high net biomass productivity while deserts have low productivity

    Self-Assessment Quiz \(\PageIndex{1}\)
    1. Desert plants have adapted to drought by having
      1. deep tap roots
      2. extensive near-surface root systems
      3. thick fleshy leaves
      4. all the above
    2. "Energy cannot be created or destroyed" is a statement of the
      1. First Law of Thermodynamics
      2. Second Law of Thermodynamics
      3. The Adiabatic Law
      4. none of the above
    3. Plant transpiration
      1. depends on the amount of water held in the soil
      2. cools the plant
      3. depends on the humidity of the air
      4. All of the above
    4. A ______ is the natural environment in which an organism lives.
      1. habitat
      2. niche
      3. ecotone
      4. formation class
    5. The function of a life-form within a community is called
      1. a niche
      2. an ecotone
      3. a habitat
      4. none of the above
    6. The process of converting solar energy, water and carbon dioxide into carbohydrates and oxygen is called
      1. photosynthesis
      2. respiration
      3. transpiration
      4. none of the above
    7. Climate and topographic barriers are more of an impediment to ___ than ____.
      1. plants; animals
      2. animals; plants
    8. Deserts generally have ___ potential evapotranspiration and ___ moisture index.
      1. high; high
      2. high; low
      3. low; low
      4. low; high
    9. Which biome can be thought of as a "global-scale" ecotone?
      1. Tundra
      2. Forest
      3. Grassland
      4. Savanna
    10. The multi-layered canpopy of the rain forest creates a(n) ____ forest structure.
      1. open
      2. closed
    1. D
    2. A
    3. D
    4. A
    5. A
    6. A
    7. B
    8. B
    9. D
    10. A

    Additional Resources

    Use these resources to further explore the world of geography

    Connections: "Vietnam's Appetite For Rhino Horn Drives Poaching In Africa" (NPR, 2013)

    World of Change: Global Biosphere (NASA Earth Observatory)


    "Invasion of the Giant Pythons" Nature (PBS) Description from the site: "Florida’s Everglades National Park is one of the last great wildlife refuges in the U.S., home to numerous endangered animals and plants, as well as alligators. But the park has become a dumping ground for a variety of non-native species, including what may be tens of thousands of Burmese pythons. Some were intentionally released by pet owners, others were set free when hurricanes hit Florida’s animal warehouses. Pythons have moved into their new home with a vengeance, thriving in the protected wilderness and disrupting its delicate ecosystem. Follow scientists and snake hunters as they study the problem and try to find solutions to the growing crisis. This film premiered February 21, 2010."

    "Alien Invasion" Online News Hour with Jim Lehrer. July 1, 2004 report on efforts to combat invasion of alien plant and animal species in the United States.

    "Hot Times in Alaska" Scientific American Frontiers. This episode investigates the impact of climate change on Alaska's ecosystems.

    World's Biggest Tiger Preserve - NPR/National Geographic Radio Expeditions visits The Hukawng Valley in Myanmar where an entire valley nearly the size of Vermont is being set aside as a tiger reserve.

    "The Birds of the Boreal" NPR/National Geographic Radio Expeditions

    "The Last American rain forest" - Morning Edition (NPR) segment from Oct. 22, 1998 reports on the last great temperate rain forest in America, Alaska's Tsongass National Forest. (8:36) (RealAudio Required)

    "Drugs and Bugs" - Ethnobotanist Mark J. Plotkin, Ph.D, talks with host David Wright about the healing secrets of the rainforest in the segment of All Things Considered from July 23, 2000. (RealAudio Required)


    Where Have All the Songbirds Gone? from the "Why Files " Web site

    Grassland Initiative (NASA EOS)

    "Root Causes of Biodiversity Loss" - CIESN, World Resources Institute.

    Web Sites

    Wild World: Terrestrial Ecoregions (NGS/WWF) - rich resource for information about global ecosystems. Organized by biogeographical realm.

    Biodiversity Hotspots - investigate endangered regions at this web site.

    This page titled 12.4: Review and Additional Resources is shared under a CC BY-SA 4.0 license and was authored, remixed, and/or curated by Michael E. Ritter (The Physical Environment) via source content that was edited to the style and standards of the LibreTexts platform; a detailed edit history is available upon request.

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