1.
State what is meant by a community.
[1 mark]
- all the populations of different species in a habitat
JD SCIENCE
Ecosystems and material cycles
Indicative marking points. Award marks for equivalent scientific or mathematical wording. Do not issue this sheet with the student worksheet.
2.
State what is meant by an ecosystem.
[1 mark]
- the community and the non-living conditions
3.
State what is meant by a producer.
[1 mark]
- an organism that makes its own food by photosynthesis
4.
State what is meant by a predator-prey cycle.
[1 mark]
- populations rise and fall out of step
5.
State what is meant by biodiversity.
[1 mark]
- the variety of species in an area
6.
State what is meant by the carbon cycle.
[1 mark]
- carbon moves between air, living things and fossil stores
7.
State what is meant by the water cycle.
[1 mark]
- evaporation, transpiration, condensation, precipitation
8.
State what is meant by eutrophication.
[1 mark]
- excess nutrients cause algal bloom, then oxygen crash
9.
State what is meant by a quadrat.
[1 mark]
- a square frame used to sample organisms
10.
State what is meant by a transect.
[1 mark]
- a line along which samples are taken
11.
Devon is asked about a community in a Edexcel Biology paper.
(a) [2 marks]
- they interact
(b) [3 marks]
- why removing one species can affect others
12.
Devon is asked about an ecosystem in a Edexcel Biology paper.
(a) [2 marks]
- includes abiotic and biotic factors
(b) [3 marks]
- why temperature is an abiotic factor
13.
Devon is asked about a producer in a Edexcel Biology paper.
(a) [2 marks]
- start of a food chain
(b) [3 marks]
- why all food chains start with a producer
14.
Devon is asked about a predator-prey cycle in a Edexcel Biology paper.
(a) [2 marks]
- more prey → more predators → fewer prey
(b) [3 marks]
- why predator numbers peak after prey
15.
Devon is asked about biodiversity in a Edexcel Biology paper.
(a) [2 marks]
- high biodiversity makes an ecosystem more stable
(b) [3 marks]
- why deforestation reduces biodiversity
16.
Devon is asked about the carbon cycle in a Edexcel Biology paper.
(a) [2 marks]
- photosynthesis, respiration, combustion, decomposition
(b) [3 marks]
- why burning fossil fuels increases CO₂
17.
A 0.25 m² quadrat contains 8 dandelions. Estimate the number in a 100 m² field.
[3 marks]
- 8 × (100/0.25)
- Final answer: 3200
18.
Five quadrats have 3, 5, 2, 6 and 4 plants. Calculate the mean.
[3 marks]
- Final answer: 4
19.
A food chain has 10 000 kJ in grass and 1000 kJ in rabbits. Calculate the efficiency of transfer.
[3 marks]
- 1000/10000 × 100
- Final answer: 10%
20.
Only 1% of 2 × 10⁶ kJ of sunlight becomes biomass in plants. How much is stored?
[3 marks]
- Final answer: 2 × 10⁴ kJ
21.
A population of 200 deer increases by 15%. What is the new population?
[3 marks]
- Final answer: 230
22.
Devon samples 10 quadrats of 1 m² in a 500 m² wood and finds a mean of 3 fungi. Estimate the total.
[3 marks]
- 3×500
- Final answer: 1500
23.
Devon carries out a random quadrat investigation of plant abundance. This is a typical Edexcel required-practical style question.
(a) [2 marks]
- Independent: area / mowing / light
- Dependent: number of plants / percentage cover
(b) [2 marks]
- same quadrat size
- so the test is fair / only one variable is changed
(c) [2 marks]
- not using random numbers
24.
Devon carries out a transect up a rocky shore or across a field. This is a typical Edexcel required-practical style question.
(a) [2 marks]
- Independent: distance along the transect
- Dependent: species abundance
(b) [2 marks]
- same interval
- so the test is fair / only one variable is changed
(c) [2 marks]
- uneven spacing
25.
Devon carries out measuring abiotic factors (light, temperature, pH, moisture). This is a typical Edexcel required-practical style question.
(a) [2 marks]
- Independent: location
- Dependent: instrument reading
(b) [2 marks]
- same time of day
- so the test is fair / only one variable is changed
(c) [2 marks]
- shading the light meter with your body
26.
Devon carries out investigating decay with milk or compost and lipase / protease. This is a typical Edexcel required-practical style question.
(a) [2 marks]
- Independent: temperature
- Dependent: pH change / mass loss
(b) [2 marks]
- same volume
- so the test is fair / only one variable is changed
(c) [2 marks]
- uneven mixing
27.
Compare biotic factors with abiotic factors.
[4 marks]
- biotic: living, e.g. predation
- abiotic: non-living, e.g. light
28.
Compare a food chain with a food web.
[4 marks]
- chain is one pathway
- web shows many linked pathways
29.
Compare decay with combustion.
[4 marks]
- both release CO₂
- decay is biological / combustion is burning
30.
Compare intensive farming with conservation.
[4 marks]
- intensive: high yield, lower biodiversity
- conservation: protects habitats
31.
Apply your knowledge of the water cycle to this situation: less transpiration
[3 marks]
- less transpiration
32.
Apply your knowledge of eutrophication to this situation: decomposers use up oxygen
[3 marks]
- decomposers use up oxygen