Safety and evidence boundary
Use supplied ecological datasets, safe non-contact observation, and paper/digital food-web models. Do not disturb wildlife or reveal sensitive species locations. Energy-flow models are ecosystem approximations and should include units, area/time scales, and uncertainty.
Explicit science instruction
Gross primary production (GPP) is the rate at which producers capture chemical energy through photosynthesis. Producers also use energy in cellular respiration. Net primary production (NPP) is commonly modeled as GPP − producer respiration and represents energy stored in new biomass over a specified area and time.
Vocabulary: GPP; NPP; respiration; biomass; productivity; producer; energy rate.
Worked example with reasoning
A grassland has GPP 2,000 kJ m⁻² yr⁻¹ and producer respiration 900 kJ m⁻² yr⁻¹. NPP = 1,100 kJ m⁻² yr⁻¹. Units matter because productivity is a rate per area and time.
Guided question
Why is NPP smaller than GPP?
Independent work
- Calculate NPP for four datasets.
- Track units.
- Explain what NPP can support in a food web.
- State one measurement limitation.
Misconception check
Plants do respire. Photosynthesis does not mean producers keep all captured energy as biomass.
Formative understanding check
GPP=1500, respiration=600. NPP?
Worked response
900 in the same energy/area/time units.
Open-book formative practice only; not an official mastery attempt or grade.
Mentor evidence conference
Ask Archaemenes to challenge your model topology, evidence classification, calculation, and stated uncertainty without substituting belief or protected answers for science mastery.
Open ArchaemenesTeacher guidance
Foundation: use an energy-budget diagram. Core: calculate with units and interpretation. Extended: compare terrestrial/aquatic productivity measures and standing biomass.
Preserve learning evidence
Keep models, data work, corrections, source classifications, and limitations in the matching Week 31 evidence field.