AQA Biology 4.7.5.2 · Triple only

Farming techniques

Two chickens, the same feed. One is kept still and warm, one runs about outside. Which gains more mass, and what does the difference cost?

Triple Science · Foundation tier

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Cold day, big appetite.

After a cold day running around you are starving.

If you had to guess, does an animal that sits still in the warm need more food, or less?

Efficiency

Where the feed goes.

The efficiency of food production can be improved by restricting energy transfer from food animals to the environment. This can be done by limiting their movement and by controlling the temperature of their surroundings. Some animals are fed high-protein foods to increase growth. Switch between the two chickens.

Indoor shed: little room to move and a controlled warm temperature, so less of the feed is used in respiration and more becomes body mass.

Why does limiting movement increase the mass an animal gains from the same feed?

Pick one.

The efficiency calculation is in Transfer of biomass.

Advantages, disadvantages, ethics

What it costs.

You should be able to evaluate the advantages and disadvantages of modern farming techniques, and understand that some people have ethical objections to some modern intensive farming methods. Tap each.

Information · made-up data for practice

Two ways of raising chickens, same feed (made up): indoor shed, 20 birds per m², 20 °C, no outdoor access, 2.0 kg body mass per 4 kg feed, meat price £3 per kg. Free range, 1 bird per m² outdoors, 1.3 kg body mass per 4 kg feed, meat price £6 per kg.

Which evaluation uses the information fairly?

Pick one.

Think again · lazy?

“Penned animals grow faster because they are lazy.”

Your call

Choose

Why does a chicken kept in a warm shed with little room gain more mass from the same feed than a free-range chicken?

Sort

Advantage or disadvantage?

Place each point about intensive indoor farming.

Tap a card, then tap the box it belongs in. Tap a placed card to take it back.

Command words in this lesson

Explain: How limiting movement or controlling temperature improves efficiency.
Evaluate: Intensive methods from given information: advantages, disadvantages, judgement.
Describe: Ethical objections some people have.

Key fact

Limiting movement and controlling temperature reduce the energy animals transfer to the surroundings in respiration, so more feed becomes body mass. High-protein feed increases growth. Some people have ethical objections to intensive methods; crowded animals spread disease, and farm antibiotic use should be restricted.

Key note · AQA 4.7.5.2 (Biology only)

Farming techniques

The efficiency of food production can be improved by restricting energy transfer from food animals to the environment.
This can be done by limiting their movement and by controlling the temperature of their surroundings: less glucose is used in respiration, so more of the feed becomes body mass.
Some animals are fed high-protein foods to increase growth.
Some people have ethical objections to some modern intensive farming methods. Crowding spreads disease; the agricultural use of antibiotics should be restricted.
Evaluate from given information: efficiency and price on one side, welfare, disease and ethics on the other, then judge.

Photograph this card. Tomorrow, cover it and say each line first.

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Saying “lazy” instead of “less respiration”?

The chicken shed and free-range figures are made up for practice.