Ecosystems and Material Cycles | Edexcel GCSE Combined Science Biology, Foundation tier (1SC0)
Ecosystems and Material Cycles
- 104 questions
- 8 subtopics
- Paper 2
- Paper 2
Ecosystems and Material Cycles is examined in Paper 2, Biology 2.
It covers levels of organisation and interdependence, abiotic and biotic factors, parasitism and mutualism, sampling with quadrats and transects and estimating population size, human impact on biodiversity, and the carbon, water and nitrogen cycles.
Sample questions from Ecosystems and Material Cycles
Answer each one closed book first, then open the answer.
-
Levels of organisation and interdependence
Place the terms community, individual organism, ecosystem and population in order from the smallest level of organisation to the largest.
Show the answer
Individual organism, then population, then community, then ecosystem. -
Abiotic and biotic factors in a community
Explain why few plants grow on the floor of a dense woodland.
Show the answer
The tree canopy absorbs most of the light, so plants below cannot photosynthesise fast enough to grow well. -
Parasitism and mutualism
Explain why a flea is described as a parasite.
Show the answer
It feeds on its host's blood, gaining food while causing the host irritation and possible infection. -
Sampling with quadrats and transects
What is a belt transect?
Show the answer
A belt transect is a line laid across a habitat along which quadrats are placed to record how the species present change with distance. -
Estimating population size from field data
Twenty quadrats, each of area 0.25 m², contain 60 buttercup plants altogether. Calculate the mean number of buttercups per square metre.
Show the answer
The quadrats cover 20 × 0.25 = 5 m², so the mean is 60 ÷ 5 = 12 buttercups per m². -
Human impact on ecosystems and biodiversity
What is eutrophication?
Show the answer
Eutrophication is the enrichment of water with nutrients such as nitrates, which causes excessive growth of algae. -
The carbon cycle
What part do decomposers play in the cycling of materials?
Show the answer
They break down dead organisms and waste, releasing the elements they contain back into the soil and the air. -
The water and nitrogen cycles
Describe how distillation turns sea water into potable water.
Show the answer
The sea water is heated so that pure water evaporates, and the vapour is then cooled and condensed, leaving the salts behind.
The 8 subtopics
One subtopic is one session. Work down the list.
| Subtopic | What it covers | Questions |
|---|---|---|
| Levels of organisation and interdependence | Individuals, populations, communities, habitats and ecosystems and their order, interdependence through food, shelter, pollination and seed dispersal, how losing one species affects others in a food web, and why an interdependent community stays balanced. | 13 |
| Abiotic and biotic factors in a community | Abiotic and biotic factors, how temperature, light, drought and pollution shape a community, what plants and animals compete for, and the cycle of predator and prey numbers. | 10 |
| Parasitism and mutualism | Parasitism and mutualism, with tapeworms, fleas and mistletoe as parasites, and oxpeckers and buffalo, cleaner fish, nitrogen-fixing bacteria in pea plants, and chemosynthetic bacteria in deep-sea tube worms as mutualistic partners. | 9 |
| Sampling with quadrats and transects | Using random quadrats to find the mean number of a plant per square metre, generating random coordinates, percentage cover, belt transects across a changing habitat, measuring light and soil moisture, sample size and sources of error, and the mean, median and mode of quadrat counts. | 15 |
| Estimating population size from field data | Scaling a quadrat mean up to a whole site, working the mean per square metre from quadrats of different sizes, why the result is only an estimate, and transect counts. | 8 |
| Human impact on ecosystems and biodiversity | Biodiversity, the harm and benefits of fish farming, non-indigenous species and their effects on native wildlife, eutrophication from fertiliser and sewage, why biodiversity keeps ecosystems stable, conserving endangered species through captive breeding and protected habitats, reforestation, and the economic value of biodiversity. | 18 |
| The carbon cycle | Why materials must be recycled, the biotic and abiotic parts of material cycles, decomposers, and the carbon cycle, with photosynthesis removing carbon dioxide, respiration and combustion returning it, carbon passing along food chains, and the effects of burning fossil fuels and clearing forests. | 14 |
| The water and nitrogen cycles | Evaporation, transpiration, condensation and precipitation in the water cycle, potable water and desalination by distillation, why sea water dehydrates, and the nitrogen cycle, with nitrogen-fixing, nitrifying and denitrifying bacteria, decomposers, legume crop rotation, fertilisers and draining waterlogged soil. | 17 |
How the guide is worked
Answering a question from memory stores it far better than reading the answer again. The guide runs that as a fixed procedure on one subtopic at a time, about twenty minutes a session.
-
Step 1 · Closed book
Cover the answers. Work through one subtopic and write down what you can. Leave blanks where you have nothing.
-
Step 2 · Open book
Go back to the top. Read each printed answer and write it out in full, including the ones you had right.
-
Step 3 · Closed book again
Same questions, same order, from memory. The gap between pass one and pass three is the session result.
Read the full method, the return schedule and the research behind it.
Nearby topics
Edexcel GCSE Combined Science Biology, Foundation tier Active Recall Guide
Every topic, not just this one. 904 questions with their answers.