Feeding Relationships Practice Questions

Question 1

4 marks

A food chain in a freshwater stream is shown below.

algae $\rightarrow$ mayfly nymph $\rightarrow$ stickleback $\rightarrow$ kingfisher

(a)

Name the producer in this food chain.

/ 1

(b)

Name the tertiary consumer in this food chain.

/ 1

(c)

Name the organism that is the prey of the stickleback.

/ 1

(d)

State the original source of the energy in this food chain.

/ 1

Question 2

3 marks

Only a small proportion of the energy in one trophic level is transferred to the trophic level above it.

(a)

Name the process carried out by all living organisms that transfers energy to the surroundings as heat.

/ 1

(b)

Give two other ways in which energy is not transferred to the next trophic level in a food chain.

/ 2

Question 3

3 marks

The table shows the biomass of three organisms in a food chain in an oak woodland.

organism	biomass in kg
oak leaves	$18\,000$
aphids	$2\,400$
ladybirds	$300$

(a)

Draw a pyramid of biomass for this food chain.

/ 2

(b)

State what the width of each bar in a pyramid of biomass represents.

/ 1

Question 0

5 marks

The diagram shows a food web for a grassland ecosystem. The arrows show the direction in which energy is transferred.

(a)

Name one secondary consumer shown in this food web.

/ 1

(b)

State the trophic level of the kestrel when it feeds on a shrew.

/ 1

(c)

A disease kills almost all of the rabbits in this grassland.

Explain the effect this could have on the population of field voles.

/ 3

Question 0

4 marks

Ecologists measured the energy contained in the grass and in the rabbits in one square metre of a sand dune each year. Their results are shown in the table.

trophic level	energy in kJ/m²/year
grass	$38\,000$
rabbits	$1\,520$

(a)

Calculate the percentage efficiency of energy transfer from the grass to the rabbits.

.............................................................. %

/ 2

(b)

Explain why the efficiency of this energy transfer is low.

/ 2

Question 0

5 marks

A farmer keeps sheep on an upland field. In one year the sheep eat grass containing $5\,600$ kg of biomass. Only $8.5\%$ of this biomass is transferred into new sheep biomass.

(a)

Calculate the mass of grass biomass that is transferred into sheep biomass.

.............................................................. kg

/ 2

(b)

Calculate the mass of grass biomass that is not transferred into sheep biomass.

.............................................................. kg

/ 1

(c)

The farmer is surprised that so little biomass is transferred into the sheep.

Explain what happens to the biomass that is not transferred into new sheep biomass.

/ 2

Question 0

6 marks

The table shows the biomass of the organisms in a woodland food chain.

organism	biomass in kg
oak leaves	$24\,500$
caterpillars	$2\,940$
blue tits	$265$
sparrowhawks	$19$

(a)

Calculate the percentage of the caterpillar biomass that is transferred into blue tit biomass.

Give your answer to 3 significant figures.

.............................................................. %

/ 2

(b)

Calculate the biomass of the sparrowhawks as a percentage of the biomass of the oak leaves.

Give your answer to 3 significant figures.

.............................................................. %

/ 2

(c)

Explain why the biomass at each trophic level in this food chain is smaller than the biomass at the level below it.

/ 2

Question 0

5 marks

A student writes: "A food chain can have as many trophic levels as you like."

(a)

Explain why food chains rarely contain more than four or five trophic levels.

/ 3

(b)

A farmer can use one hectare of land either to grow wheat for people to eat, or to graze cattle that will be eaten by people.

Suggest why using the land to grow wheat can feed more people.

/ 2

Question 0

6 marks

In one square metre of open ocean, $2\,500\,000$ kJ of light energy falls on the surface each year.

The phytoplankton transfer $1.4\%$ of this light energy into their biomass.
The transfer of energy from phytoplankton to zooplankton is $18\%$ efficient.
The transfer of energy from zooplankton to herring is $9\%$ efficient.

(a)

Calculate the energy stored in the biomass of the phytoplankton each year.

.............................................................. kJ/m²/year

/ 2

(b)

Calculate the energy transferred into the biomass of the herring each year.

.............................................................. kJ/m²/year

/ 2

(c)

Calculate the percentage of the light energy falling on the sea surface that ends up in the biomass of the herring.

Give your answer to 3 significant figures.

.............................................................. %

/ 2

Question 0

6 marks

A scientist compared the efficiency of energy transfer from plant material to two different farm animals. Her results are shown in the table.

food chain	percentage of energy in the plant material transferred to the animal's biomass
water plants $\rightarrow$ carp (a fish kept in ponds)	$20\%$
grass $\rightarrow$ cattle	$4\%$

(a)

A farmer feeds $12\,000$ kJ of plant material to the carp and $12\,000$ kJ of plant material to the cattle.

Calculate how much more energy is transferred into carp biomass than into cattle biomass.

.............................................................. kJ

/ 2

(b)

Explain why the transfer of energy to the carp is more efficient than the transfer of energy to the cattle.

/ 4

Key Concepts in Biology

Cells & Control

Genetics

Natural Selection & Genetic Modification

Health, Disease & the Development of Medicines

Plant Structures & their Functions

Animal Coordination, Control & Homeostasis

Exchange & Transport in Animals

Ecosystems & Material Cycles

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