The unit in one line
How energy and matter move through pond and forest ecosystems, how human activity upsets the carbon, nitrogen and ozone balance, and how Nepal's vegetation changes with altitude and over time. 4 of Botany's 40 questions over three chapters.
Read in this order
- Ecosystem ecology (9 min) — pond and forest structure, food chains and webs, the ten per cent law, ecological pyramids and the biotic interactions.
- Biogeochemical cycles and ecological imbalances (9 min) — the carbon and nitrogen cycles with the organism at each step, then the greenhouse effect, acid rain, ozone depletion and climate change.
- Vegetation and adaptation (9 min) — Nepal's forest types by altitude, invasive species, succession, and the seral stages of the hydrosere and xerosere.
About 25 minutes in all. Pollution, protected areas and conservation are taught in Zoology: see the Zoology unit 8 map.
How it is asked
MEC sets the paper roughly half recall, a third understanding and a fifth application. Recall here is which bacterium does which step of the nitrogen cycle, which gas warms most per molecule, and which forest grows at which altitude. Understanding is why a pyramid of biomass can be inverted in a pond, or why rain below pH 5.6 counts as acid. Application is a described forest or seral stage to place, or energy to follow along a food chain.
Then practise
Each chapter has a fixed-length chapter test under Practice › Topics, drawn from questions written to that chapter's scope. Sit it after reading; a second sitting a week later shows whether it stuck.