HS-LS2-4: Biomass and Trophic Levels

Use mathematical representations to support claims for the cycling of matter and flow of energy among organisms in an ecosystem.

Clarification Statement: Emphasis is on using a mathematical model of stored energy in biomass to describe the transfer of energy from one trophic level to another and that matter and energy are conserved as matter cycles and energy flows through ecosystems. Emphasis is on atoms and molecules such as carbon, oxygen, hydrogen and nitrogen being conserved as they move through an ecosystem.

Assessment Boundary: Assessment is limited to proportional reasoning to describe the cycling of matter and flow of energy.


The following assessments were created by science teachers hoping to better understand the NGSS. In most cases teachers went from standard to assessment in around an hour.  These are drafts and should be used accordingly. Feel free to improve these assessments or contribute to the collection. Learn more about assessment design here.




Trophic levels
Ecological pyramids (e.g. energy, biomass, numbers)
Matter cycling
Energy flow


Learning Plans


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