Unit 01 · Ecosystems & Energy Flow
This unit builds from the sun outward: how energy enters an ecosystem through primary producers, climbs the trophic levels of a food web, and loses roughly ninety percent at every step. You’ll measure life in the field with quadrats and transects, separate gross from net primary productivity, and see why a handful of keystone species hold a whole community together. Mastery means you can read an ecosystem as a flow of energy and matter, not a list of organisms to memorize.
| Criterion | Not yet | Approaching | Mastered |
|---|---|---|---|
| Trophic levels & food webs | Confuses producers, consumers, and decomposers or their roles. | Names the trophic levels but stumbles tracing energy through a food web. | Reads any food web fluently and traces energy from producer to top predator, naming each trophic level. |
| Energy flow & the 10% rule | Thinks energy is recycled through an ecosystem the way matter is. | States the 10% rule but cannot apply it across levels. | Calculates the energy available at each trophic level from the 10% rule and explains why food chains stay short. |
| Primary productivity (GPP & NPP) | Uses gross and net productivity interchangeably. | Defines GPP and NPP but cannot separate them in data. | Distinguishes GPP, NPP, and respiration, and computes NPP from field or dataset measurements. |
| Biomes, niches & keystone species | Cannot say why one species matters more than another to a community. | Recalls the term “keystone species” but not its effect. | Predicts how removing a keystone species cascades through a food web and links biomes to their limiting factors. |
| Field technique (quadrat & transect survey) | Places the quadrat carelessly or miscounts the sample. | Runs the survey but records the data inconsistently. | Runs clean quadrat and transect sampling, estimates population density and biodiversity, and defends the sampling design. |
| Integration (cross-domain) | Treats the science as isolated facts; makes no cross-domain connection. | Names a link to history, reading, or writing but cannot defend why it matters. | Connects the unit to its anchor across History · Reading · Writing (plus chosen electives) and defends why the connection matters. |
“A thousand units of energy in the grass become about a hundred in the rabbits and ten in the fox — ninety percent is lost as heat at every step. That’s why you never see a long chain of predators: there isn’t enough energy left to feed them. That’s something I can reason out, not a fact I memorized.”
“The grass gives energy to the rabbit and… the fox eats it? And the energy just kind of keeps going up, I think — the big animals have the most.”
You demonstrate this unit through quadrat and transect field surveys plus short oral checks where you reason from energy flow aloud — not a multiple-choice test. A criterion counts as mastered only when you can both run the survey and justify the ecology behind it. Mastery is demonstrated, not awarded.
A 5-page clipboard packet — unit overview, key terms, the mastery rubric, anchor examples, and a score sheet you can print and grade against.