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Playbook

Ecology and Environment

12 q · 0% HARD. Environment and Biodiversity (6), Ecosystems + Biomes + Ecological Interactions (6 · biome-feature identification, food-chain construction, mutualism/commensalism/parasitism). Verify strand because the dominant question shape is multi-statement evaluation ('Consider the following statements about ecosystems... which are correct?'). Zero HARD — guaranteed marks if you drill the verification habit.

questions in the bank
12
tagged HARD
0%
subtopic(s)
2
worked examples
2

When you’ll see it

A biome-identification question (tropical rainforest features, taiga, savanna), a food-chain construction, a producer/consumer/decomposer identification, an ecological-interaction question (mutualism / commensalism / parasitism), or a 'consider the following statements about ecosystems' multi-statement evaluation.

How this chapter is tested

12 q in 10 years, ZERO HARD across the whole window. Verify strand — half the questions are multi-statement evaluation ('Consider the following statements... which are correct?'). Environment and Biodiversity (6 q) covers biome-feature identification and ecological awareness. Ecosystems, Biomes and Ecological Interactions (6 q) covers food chains, ecological interactions, biome classification.

Major land biomes you need: Tropical rainforest (high rainfall + temperature year-round, most biodiverse, evergreen broadleaf), Savanna (grassland + scattered trees, wet + dry seasons), Desert (low rainfall, extreme temperature variation), Temperate deciduous forest (4 seasons, leaf-shedding in autumn), Taiga / boreal forest (cold + coniferous, large biome by area), Tundra (frozen subsoil = permafrost, treeless, lichen + moss). The 2024 PYQ tests 'high rainfall + temperatures cold to mild + evergreen' → temperate rainforest (a less-tested biome — usually it's tropical that comes up).

Ecological interactions: Mutualism = both benefit (+/+) — lichen, mycorrhiza, bee + flower. Commensalism = one benefits, other unaffected (+/0) — barnacles on whales. Parasitism = one benefits at cost to other (+/−) — tapeworm in human gut. Predation (+/−). Competition (−/−). Food chain = unidirectional flow of energy (producer → primary consumer → secondary consumer → tertiary → decomposer). Only ~10% energy transfers between trophic levels (90% lost as heat). Food web = interconnected food chains.

The sub-skills

The rules and habits that decide whether you get a question right.

  • Biome identification by features

    Tropical rainforest: hot + wet year-round, broadleaf evergreen, most biodiverse. Savanna: tropical grassland + scattered trees, wet/dry seasons. Desert: very low rainfall, large temp swings, succulents + small mammals. Tundra: permafrost, treeless, lichens + mosses, short summer. Taiga: cold + coniferous, large area. Coral reef: warm + shallow tropical ocean, second-most biodiverse.

  • Food chain + trophic levels

    Producers (autotrophs — plants, algae) → Primary consumers (herbivores) → Secondary consumers (carnivores eating herbivores) → Tertiary consumers (top predators) → Decomposers (bacteria + fungi). ~10% energy transfers per trophic level. Food web = interconnected chains.

  • Ecological interaction types

    Mutualism (+/+): both benefit (lichen = fungus + alga; mycorrhiza = fungus + plant root; bee + flower). Commensalism (+/0): one benefits, other unaffected (barnacles on whales). Parasitism (+/−): one benefits at cost (tapeworm in gut, Plasmodium in human, mosquito feeding). Predation (+/−). Competition (−/−). Amensalism (0/−).

  • Multi-statement evaluation discipline

    Read each statement INDEPENDENTLY before pairing with the answer options. Judge each as true / false against your knowledge. Then match to the option that lists EXACTLY the correct subset. Common trap: option that lists 2 of 3 correct statements (when there are actually 3 correct) — partial-credit distractor.

2 worked examples from the bank

Real past-year questions illustrating the playbook. Click to reveal options + solution.

Example 1Ecology and EnvironmentMODERATE
Identify the land biome on the basis of the given characteristics : 1. Their climates are characterised by high rainfall and temperatures that vary from cold to mild. 2. These forests contain primarily deciduous trees – including maple, oak, hickory and beechwood. 3. Raccoons, opossums, bats and squirrels are found in the trees. Select the correct land biome from the options given below :

[Q119 · Apr · 2024]

Example 2Ecology and EnvironmentEASY
Relationship between a flower and honey-bee will help the flower for/in

[Q71 · Sep · 2023]

Traps to expect

Distractor shapes specific to this chapter. The page-wide Traps section covers the bank-level patterns.

  • Mutualism vs commensalism confusion

    Mutualism = BOTH benefit (lichen, mycorrhiza, bee + flower). Commensalism = ONE benefits, other UNAFFECTED (not harmed). Distractor labels lichen 'commensalism' (wrong — both partners benefit; the alga provides food, the fungus provides shelter + minerals). Always identify what each partner gets before classifying.

  • Decomposers as consumers

    Decomposers (bacteria + fungi) are NOT classified as consumers — they form a separate functional group that breaks down dead organic matter. They recycle nutrients back to producers. Distractor groups them with carnivores or omnivores. Producers + consumers + decomposers are the three functional groups in an ecosystem.

  • Energy increases up the food chain

    WRONG. Energy DECREASES up the food chain (only ~10% transfers per trophic level). Top predators have the LEAST available energy → smallest populations. BIOMAGNIFICATION of toxins (DDT) is what increases up the food chain, not energy. Distractor confuses energy flow with toxin accumulation.

Drill every ecology and environment question

12 questions from the bank, scoped to 2 bundled subtopics.

Drill the 12 questions

Related playbooks

Often paired with this one — drill these next if you found the worked examples above tractable.