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For more information, please see full course syllabus of AP Environmental Science
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Lecture Comments (2)

1 answer

Last reply by: Bryan Cardella
Sat Apr 18, 2015 12:24 PM

Post by Caleb Kierum on April 17, 2015

What is the difference between deetritivores and decomposers?  I understand the difference in there definition... but don't they both get energy from consuming non-living things?


  • Key terms include: ecosystem, community effect, keystone species, producers/autotrophs, consumers/heterotrophs, food chain, food web, trophic level
  • Energy flow is important to consider. It cycles from the environment to organisms, back to the environment. The 1st and 2nd laws of thermodynamics help make sense of energy flow through a system
  • Biomass, biological production (gross and net), primary/secondary production, and energy efficiency are all important to consider when studying organisms in an ecosystem
  • Ecological successions can be either primary or secondary
  • Facilitation, interference, and life history differences can all have an affect on succession


Lecture Slides are screen-captured images of important points in the lecture. Students can download and print out these lecture slide images to do practice problems as well as take notes while watching the lecture.

  • Intro 0:00
  • Key Terms 0:05
    • Ecosystem
    • Community Effect
    • Cycling of Chemical Elements and Flow of Energy
  • Food Webs 4:18
    • Network of Food Chains
    • Trophic Level
    • Ecosystem Boundaries
  • Energy Flow 7:20
    • Ecosystem Energy Flow
    • Laws of Thermodynamics
    • Chemistry of Energy Flow
  • Biomass and Biological Production 11:51
    • Biomass
    • Biological Production
    • Primary Production vs. Secondary Production
    • Energy Efficiency
  • Succession, Part I 17:36
    • Ecological succession
    • Examples
    • Commonalities of Succession
    • Chemical Cycling
    • Facilitation
    • Interference