• Producers, namely green plants and algae, are able to produce their own energy and biomass through photosynthesis.
• Consumers eat other organisms for their energy and biomass.
• Energy flows from the food to the consumer.
• The amount of energy transferred decreases from one part of the food chain to the next because it’s lost through waste and respiration.
• A pyramid of biomass is a visual representation of biomass being passed along a food chain. The bigger the bar the more biomass available.

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TEST IT!

1. Look at the food chain below.

humans

?

sheep

?

grass

a) Only some of the energy originally absorbed by the grass from the Sun will be taken in by the rabbit. How does a plant use the rest of this energy?

b) Name two ways in which more energy can be kept in a food chain.

i. ____________________________________________
ii. ____________________________________________

2.Mr Rogers breeds ducks for food in terms of meat and eggs. The table below shows how energy moves in and out of the duck.

Energy in	Energy lost	Energy transferred
1000 kJ food for the duck	500 kJ in respiration___ kJ lost in faeces120 kJ in egg

a) Mrs Granger buys a duck to make stew. How much energy will be transferred from the duck to Mrs Granger and her family?

b) How much energy was lost through the faeces?

c) Mr Rogers’ ducks are free-range which means he lets them move around outside. In his neighbour’s farm the chickens are kept in cages. Why would these chickens have more energy to transfer to humans than the free-range ducks?

3. Look at the incomplete food chain below.

Grass Snail Bird Cat

a) Draw in the arrows to show the flow of energy.

b) A food chain shows the flow of energy from one organism to the nest. Explain what a pyramid of biomass represents.

c) Fill in the sentences using the correct word from below.

primary consumer producer decomposers secondary consumer

i. A _______________ makes its own food.

ii. _______________ tend to eat other animals.

iii. _______________ feed on decaying plant and animal matter.

ANSWERS

a) Respiration

b)

i. By making the chain shorter.
ii. By keeping animals in enclosed spaces.

a) 270kJ

b) 230kJ

c) Because they’re not allowed to move around as much and so use less energy.

a) Grass ? Snail ? Bird ? Cat

b) A pyramid of biomass is a visual representation of the amount of biomass being passed from one organism to the next. The larger the bar the more biomass there is at that stage.

c)

i. producer

ii. secondary consumer

iii. decomposers