HS-LS2-4 | Energy Flow and Matter Cycling
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 such as a pyramid of biomass/energy 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.
Assessment
What assessment of HS-LS2-4 might look like on a NY state exam.
Performance Level Descriptions
PLDs communicate the knowledge and skills expected of students to demonstrate proficiency in each Learning Standard. NYS assessments classify student performance into one of five levels.
Vocabulary
Terms from the Biology Glossary that come from this standard or from the released exam questions that assess it.
- algae
- atmosphere
- biomass
- carbon
- cellular respiration
- claim
- conservation of energy
- conservation of matter
- cycling of matter
- design solution
- ecosystem
- energy flow
- energy pyramid
- energy transfer
- flow of energy
- food web
- hydrogen
- matter
- matter cycle
- nitrogen
- oxygen
- pyramid of biomass
- soil
- trophic level
- waste
- autotroph (autotrophic nutrition) – June 2025
- carbon pool – June 2025
- carbon storage – June 2025
- carnivore – June 2025
- cell – Aug 2026
- closed system – June 2025
- compound – June 2025
- decomposition – June 2025
- ecological pyramid – Aug 2026
- fruiting body – Aug 2026
- fungus – Aug 2026
- herbivore – June 2025
- hyphae – Aug 2026
- mycelium – Aug 2026
- ocean – June 2025
- photosynthesis – Aug 2026
- population – June 2026, June 2025
- prey – June 2025
- producer – June 2025
- rainforest – June 2026
- sediment – June 2025
- species – Aug 2026
- ten percent rule – Aug 2026 Humongous Fungus labels the levels of an ecological pyramid 100%, 10% and 1% of the energy; the June 2025 Organisms of the Tibetan Plateau rubric credits "energy is lost to heat as you move up trophic levels".
Resources
Examples and discussion of resources for the learning, teaching, and assessment of HS-LS2-4.
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NGSS Dimensions
Performance expectation HS-LS2-4 was developed using the following elements from the NRC document A Framework for K-12 Science Education:
- Using Mathematics and Computational Thinking
- Use mathematical representations of phenomena or design solutions to support claims
- LS2.B: Cycles of Matter and Energy Transfer in Ecosystems
- Plants or algae form the lowest level of the food web. At each link upward in a food web, only a small fraction of the matter consumed at the lower level is transferred upward, to produce growth and release energy in cellular respiration at the higher level. Given this inefficiency, there are generally fewer organisms at higher levels of a food web. The chemical elements that make up the molecules of organisms pass through food webs and into and out of the atmosphere and soil, and they are combined and recombined in different ways. At each link in an ecosystem, matter and energy are conserved.
- (NYSED) When matter is cycled through organisms and ecosystems, some of the matter reacts to release energy for life functions, some is stored in newly made structures, and some is eliminated as waste.
- Energy and Matter
- Energy can be transferred between one place and another place, between objects and/or fields, or between systems.