A farmer grows a crop of maize on part of the farm. Some of the maize is fed to cattle, and the cattle are later eaten by people, forming a short food chain...
Question 1 Report
A farmer grows a crop of maize on part of the farm. Some of the maize is fed to cattle, and the cattle are later eaten by people, forming a short food chain. The way that energy flows along this chain is shown in the diagram, and the amount of energy available in the maize and in the cattle over one year is given in the table. Only some of the energy stored in the maize is passed on to the cattle, and only some of the energy in the cattle then reaches the people.
| Stage in food chain | Energy / kJ/m2/year |
|---|---|
| Maize | 15000 |
| Cattle | 1200 |
(a) State the original source of the energy that the maize uses to make its food. [1]
(b) Using the table, calculate the percentage of the energy in the maize that is transferred to the cattle. Show your working. [2]
(c) Describe three ways in which energy is lost from the cattle and so does not pass on to people. [3]
(d) State what is meant by the term herbivore. [1]
(e) Name the process in living cells that releases energy from food and produces heat. [1]
Answer Details
This question is about the flow of energy along a food chain.
(a) [1] The Sun (sunlight) [1] is the original energy source, trapped by the maize during photosynthesis.
(b) [2] Divide the energy in the cattle by the energy in the maize and multiply by 100: \[ \frac{1200}{15000} \times 100 \] [1] \[ = 8\% \] [1].
(c) [3] Any three ways in which energy is lost from the cattle and so is not passed on to people: in respiration, much of it is released as heat that keeps the body warm; energy is used for movement; energy is lost in egestion (undigested material in faeces); and energy is lost in excretion (for example in urine) [3, 1 each].
(d) [1] A herbivore is an animal that eats only plants (producers) [1].
(e) [1] Respiration [1].
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