Questions where students often pick the tempting wrong answer — make sure you know the right one:
How do decomposers return carbon to the atmosphere?✗ Decomposers release carbon by physically breaking matter into smaller pieces.✓ They respire — breaking down dead organic matter and releasing CO2.
Why are food chains usually limited to about 4 or 5 trophic levels?✗ There aren't enough types of animals to fill more trophic levels.✓ Only ~10 percent of energy is transferred between trophic levels; eventually too little energy remains to support another level.
Why is interspecific competition between similar species important?✗ Competition only happens between predators and their prey.✓ Two species cannot occupy exactly the same niche indefinitely — competition often leads to displacement or niche divergence.
In quadrat sampling, why are quadrats placed randomly?✗ To save time✓ To avoid bias in the sample
Is energy created as it passes up a food chain?✗ Energy is created at each trophic level, so top predators have the most.✓ No — energy is transferred and much is lost (mainly as heat) at each level, so only about 10% passes on.
Practise Ecology — free games
Test yourself with these quick revision games for this topic:
