Ecology and Environment
MYP Year 5 Biology — Ecology and Environment
Ecology is the unit where biology stops being about one organism under a microscope and starts being about systems under pressure — energy moving through chains, chemicals concentrating up them, and human decisions (a plantation, a fertiliser bag, a captive breeding budget) reshaping the whole thing. Every exam question here does the same move: gives you a real, messy scenario — DDT in a pond, algae on a lake, rhinos in a paddock — and asks you to apply one clean underlying mechanism to it. Learn the five mechanisms (energy flow, biomagnification, limiting factors, species-area relationships, conservation trade-offs) properly and the scenarios stop being scary.
Overview — The Shape of the Chapter
What this unit actually tests
Ecology sits on four pillars that never separate on paper: what an ecosystem is built from (biotic/abiotic factors, trophic levels), how energy and matter move through it (food webs, pyramids), how much variety of life exists and how it's protected (biodiversity, conservation), and how humans are currently breaking all three (habitat loss, pollution, climate change). Almost every exam item is a hybrid of at least two pillars — a DDT question is trophic levels and human impact; an island species-count question is biodiversity and data-processing.
- The command term decides the mark scheme more than the biology does — 'Discuss' and 'Explain' are graded completely differently even on the same fact.
- Real data (tables, species counts, concentration figures) appears constantly — you are expected to quote numbers, not just describe direction.
- Diagrams in this unit are almost always cause-and-effect chains (arrows matter) rather than static labelled structures.
The shape of the chapter
Command terms that decide your mark in this unit
| Command term | What it demands | AO | Mark-earning move |
|---|---|---|---|
| Define | Give the precise general meaning, no example required | Criterion A | One clean sentence stating what the term IS, not what it does in this scenario. |
| Describe | Give a detailed account of a pattern using the data given | Criterion A/C | Quote actual figures or the direction/rate of a trend — 'it decreases' alone scores nothing. |
| Explain | Give reasons — the mechanism linking a cause to an effect | Criterion A | State the 'why', not a repeat of the 'what' already given in the stem. |
| Discuss | Present more than one viewpoint and reach a balanced conclusion | Criterion D | Cover at least two sides before any judgement — a one-sided opinion caps at half marks. |
| Deduce | Reach a conclusion from given data, showing the reasoning | Criterion C | Show the working/logic that produces the number — the final answer alone loses marks. |
| Construct | Build a diagram, graph or model following correct conventions | Criterion B/C | Label every stage and every arrow direction — an unlabelled or reversed arrow loses that specific mark. |
| Evaluate | Weigh strengths and limitations to judge value or validity | Criterion D | State a clear final judgement backed by at least one strength AND one limitation. |
| Identify | Select or name the specific relevant feature | Criterion A/C | Give only the named answer — extra explanation isn't required and isn't rewarded. |
Key point
Overview