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Science · Grade 9

Matter and Energy in Ecosystems

Learners place organisms at trophic levels in food webs, calculate gross and net primary production and the efficiency of energy transfer between levels, and explain pyramids of numbers, biomass and energy, including inverted ones. They then model the carbon cycle at ecosystem and global scale, including anaerobic decomposition and fossil carbon, and the nitrogen cycle with its microbes, writing balanced equations for key steps.

  • 5 lessons
  • About 125 minutes
  • Matter and energy in ecosystems check: 12 questions
  • Ways to answer: balance equations, choose an answer, label a picture, match pairs, type a number and put in order
See plans Included with Family, Teacher and School plans. Open in PlayOwl

What learners will discover

  • Place organisms at trophic levels in food chains and webs, identify producers, consumers, decomposers and detritivores, and predict effects of changes in a web.
  • Calculate gross and net primary production and energy-transfer efficiency, and use them to explain pyramids of energy, biomass and numbers.
  • Model the carbon cycle at ecosystem and global scale, including aerobic and anaerobic decomposition, fossil fuels and carbon budgets.
  • Model the nitrogen cycle (fixation, ammonification, nitrification, assimilation, denitrification) and explain the roles of microbes and decomposers.

Lessons

  1. Food webs and trophic levels 8 steps5 practiceabout 22 min
  2. Energy flow and transfer efficiency 8 steps5 practiceabout 26 min
  3. Pyramids of numbers, biomass and energy 7 steps4 practiceabout 22 min
  4. The carbon cycle 9 steps6 practiceabout 27 min
  5. The nitrogen cycle and decomposers 9 steps6 practiceabout 26 min
  6. Matter and energy in ecosystems check 12 questions at the end

Keep exploring

More 9th grade science

Guide for grown-ups