How can one carbon atom pass through air, water, organisms and rock-related stores?
Submit: An evidence record, explanation and revision.
Related lesson: Ecology and Sustainability
This is a teacher-led extension beyond the short lesson. The task supplies a performance opportunity; completion alone does not certify mastery, full NGSS coverage or state alignment.
Teacher review guideBuild the idea
Photosynthesis transfers carbon from inorganic carbon sources into organic matter. Respiration returns carbon dioxide to air or water. Carbon also exchanges through dissolution, burial, weathering and other geological processes over different timescales. A carbon model needs the atmosphere, hydrosphere, biosphere and geosphere; not every arrow represents the same process or speed.
Science / engineering practice
Developing and using modelsCore idea
Photosynthesis and respiration contribute to carbon cyclingCrosscutting concept
Systems and system modelsEvidence and model inputs
Model cards: atmospheric CO₂, dissolved ocean carbon, phytoplankton, consumer, decomposer, sediment organic carbon and carbonate rock. Use a fast biological loop and a slower burial/geological route. Do not imply that photosynthesis directly manufactures a carbonate rock or that all buried carbon quickly returns.
Keep actual observations, published findings and invented model cases labeled separately. If a source or required equipment is unavailable, pause that part with a teacher; do not invent results.
Materials and preparation
Paper, graph paper or spreadsheet, and the linked readings.
Grade-level scope
Conceptual models across spheres; no complete biochemical pathway or numerical global budget required here.
Do the work
- Place cards in spheres, allowing an organism in water to be described as biosphere within a hydrosphere setting.
- Draw and label photosynthesis and respiration arrows in terrestrial and aquatic contexts.
- Add dissolution, sediment burial and a geological return route with slower-timescale labels.
- Trace one carbon atom through a possible sequence and identify where energy transformations occur.
- Revise a model that leaves out a sphere or labels every return arrow respiration.
Learner worksheet
Write on paper or type here and print. Entries stay in this page’s memory and are lost when you leave or reload; they are not saved or submitted.
Check your reasoning
- Is ocean life part of the biosphere?
- Which process incorporates CO₂ into organic matter?
- Is burial the same as respiration?
- Does a closed arrow loop imply equal flow rates?
Teacher review guide
Review the actual deliverable and discuss the reasoning. For each criterion, use 0 when evidence is absent or fundamentally incorrect, 1 when partly supported with a material error or omission, and 2 when accurate, supported and complete for the stated task. Maximum 8 points is a task score, not a proficiency certification. Give feedback and allow revision.
- Includes and connects all four spheres.
- Correctly labels photosynthesis and respiration.
- Distinguishes biological and geological pathways.
- Tracks carbon with timescale and energy annotations.
Answer guidance for the reasoning checks
Is ocean life part of the biosphere?
Yes, while interacting with the hydrosphere.
Which process incorporates CO₂ into organic matter?
Photosynthesis.
Is burial the same as respiration?
No. Burial stores material; respiration transforms organic matter and releases CO₂.
Does a closed arrow loop imply equal flow rates?
No. Rates and reservoir sizes require data.
Access, support and extension
Offer read-aloud support, labeled diagrams, larger print or an oral/recorded explanation while preserving the scientific reasoning. A partner or teacher can handle physical manipulation while the learner plans, records and interprets. Use a teacher-provided measured dataset only when its provenance and limitations are explicit; it does not replace conducting an investigation when that is the assessed practice. For greater independence, remove prompts and ask learners to compare a second explanation or test another justified revision.
Sources and standard reference
- Official NGSS HS-LS2-5 performance expectation — inspect the practice, core idea, crosscutting concept and assessment boundary.
Instructional text and hypothetical cases are original. Linked source readings supply published evidence where specified. Teachers should judge fit with their course and state requirements.