9.2 Feeding Relationships

Figure 1 shows a food chain in an ecosystem that has five different organisms occupying five trophic levels, A, B, C, D and E.

Figure 1

Decomposers are not shown in the food chain in Figure 1.

Identify which trophic level decomposers would occupy and explain the role these microorganisms play in an ecosystem.

Figure 2 below shows the energy transferred by each organism in one year.

Explain why organism D would transfer much less energy than organism A.

Explain why food chains rarely have more than five trophic levels.

Figure 1 shows the flow of energy through a food chain in a habitat over the course of one year. The figures are in kJ m^–2.

Figure 1

Calculate the percentage of the energy in sunlight that was transferred into energy in the mayfly larvae

Show your working.

Give your answer in standard form.

Explain how energy from sunlight is converted into biomass in the algae.

Suggest explanations for the difference in the amount of energy transferred from the trout to the humans.

Two food chains are shown below:

Food chain 1: Soya bean plants → Salmon  → Human

Food chain 2: Soya bean plants → Human

Figure 1 shows some data about the energy transferred between organisms in the food chains.

Figure 1

Using the information provided, compare the efficiency of these two food chains.

Figure 2 below shows a pyramid of numbers and a pyramid of biomass for an area of woodland.

Figure 3 shows a food chain in a woodland area.

Figure 3

Energy from the sun is captured by the plants in the wood.

Describe and explain the route of this energy through the food chain after it has been captured by the plants in the wood.

Figure 1 contains information about two farms. Both farms are of similar size and have similar conditions.

Figure 1

The data in Figure 1 show that farms like Haverstock Farm can be more than 12 times as efficient at meeting the food energy requirements for our growing human population than farms which grow feed for livestock.

Explain why Haverstock Farm is much more efficient at meeting human food energy requirements

Figure 2 shows a food web found in a woodland ecosystem.

Figure 2

A student investigated fish food.

The student added some fish food to a blue liquid in a test tube.

The solution turned from blue to purple.

(i)

Use words from the box to complete the sentences.

(2)

The blue liquid was .................................... solution.

The purple colour showed that the fish food contained .....................................

(ii)

The blue solution may be harmful if swallowed.

Which procedure is a health and safety precaution needed for this investigation?

(1)

Fish eat fish food.

The fish food contains energy.

Some of this energy is used by the fish for growth.

Figure 1 shows this energy transfer.

Each square in Figure 1 represents 1kJ of energy.

Figure 1

Calculate the percentage of energy from the fish food that has been used in the growth of fish.

(2)

(ii)

Describe what happened to the fish food that was eaten but was not used in the growth of the fish.

(2)