Varieties, intensive farming and plant hormones
Distinguish improved plant and animal varieties, intensive farming and agricultural uses of plant hormones by their purposes.
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Three ways to change food production
Farmers can improve the type of plant or animal they grow, change how it is managed, or regulate a plant’s growth and development. These methods do different jobs and can be used together.
Try this first: A farm chooses a higher-yield fruit variety, then treats the harvested fruit so it ripens together. Are these the same production method? Explain your answer.
Improved varieties change the type grown
An improved variety is a selected or bred type of plant or animal with useful inherited characteristics. A crop variety might give a larger harvest or resist a disease. An animal variety might grow well under the farm’s conditions. These are changes to the type being grown, rather than extra fertiliser or a new feeding schedule.
“Improved” does not mean best in every setting. Compare varieties under the same growing conditions, and judge the particular characteristic tested. A higher-yield variety still needs suitable food or mineral nutrients, water and other conditions.
Intensive farming changes the management
Intensive farming uses substantial inputs and care to increase production from the available area or resources. Crop systems can manage nutrient supply, watering and growing conditions. Chicken farms can manage feed, housing and animal health. Fish farms can manage feeding, water quality and stocking density, the number of fish kept in a given space.
Putting more animals into a space is not sufficient on its own: overcrowding, poor water quality or disease can reduce production. Judge the system’s output alongside its use of resources, waste and effects on animal health. An improved variety can also be farmed intensively; one term describes the variety and the other its management.
Plant hormones regulate responses
Plant hormones are chemical signals that regulate growth and development. Their agricultural uses include:
- Weed killing: some hormone-based weed killers disrupt the growth of unwanted plants.
- Regulating growth: treatments can help control growth, for example encouraging roots to form on plant cuttings.
- Regulating fruit ripening: a treatment can help suitable harvested fruits ripen at the required time.
The treatment must suit the plant and intended response. A hormone that affects ripening does not supply mineral nutrients as fertiliser does, and not every fruit responds in the same way. For these production methods, focus on the method, its purpose and the evidence of its effect.
Compare the methods
- Improved variety
- Which type of plant or animal is grown?
- Intensive farming
- How is production managed?
- Plant-hormone use
- Which growth or development response is regulated?
Worked examples
Modelled example 1
A crop type and a farming system
Problem
Two farms use the same improved crop variety. One carefully controls water and nutrients in a limited growing area. Distinguish the variety from the intensive management.
Study the worked solution
Ask what has changed
Method
Separate the type of crop from the way it is grown.
Reason
An improved variety has useful inherited characteristics; intensive farming concerns management and inputs.
Working
Both farms use the improved variety. Managing water and nutrients intensively describes a farming method. The same improved variety can be grown under different management conditions.
Common misconception 2
Does a ripening treatment feed the plant?
Learner response
A learner says, “A plant hormone used to regulate fruit ripening supplies mineral nutrients, so it is fertiliser.” Correct the mechanism and name two other agricultural uses of plant hormones.
Explain what is regulated
Hints
Hint 1: compare the functions
Fertiliser supplies mineral nutrients; hormones regulate responses.
View solution step by step
Correct the role
Method
Describe a hormone as a signal regulating a response, rather than a mineral nutrient.
Reason
Controlling when a fruit ripens is different from supplying the materials needed for growth.
Working
Plant hormones regulate growth and development. Other agricultural uses include hormone-based weed killing and regulating plant growth.
Challenge 3
Match each production method to its purpose
Problem
A farm chooses a higher-yield fruit variety and needs its harvested fruit to ripen together. Name the two distinct production methods.
Match each aim to a named method
Hints
Hint 1: first method
A selected higher-yield type is an improved variety.
Hint 2: second method
Plant hormones can regulate fruit ripening.
View solution step by step
Identify the selected type
Method
Name the higher-yield fruit type as an improved plant variety.
Reason
An improved variety has selected useful characteristics; it is not simply extra fertiliser.
Working
higher-yield selected type → improved plant variety
Identify the regulator
Method
Name plant-hormone use for coordinated fruit ripening.
Reason
Plant hormones can regulate when suitable fruits ripen.
Working
coordinated ripening → plant hormone
Practise independently
Match each aim to a method: choose a crop that resists a disease, manage chicken feeding and housing to increase output per area, and control when suitable fruit ripens.
Need a hint?
Ask whether the change concerns the variety, the management or a regulated
response.
Check your answer
Choosing a disease-resistant crop is using an improved variety. Managing
chicken feeding and housing is intensive animal farming. Regulating fruit
ripening uses plant hormones. None of these descriptions alone proves that the
system is sustainable or that it works best everywhere.
Think like a scientist
A fish farm uses a variety selected for good growth and also manages fish intensively in enclosures. Name the two production methods.
Check the reasoning
The selected fish are an improved animal variety; managing them intensively in enclosures is intensive farming of farm animals.
Remember: One description concerns the variety; the other concerns how it is managed.
One-minute check
Without looking back, give one plant and one animal example for improved varieties or intensive farming. Then name the three agricultural uses of plant hormones and explain why hormones are not mineral fertilisers.
Check the connected sources-of-food ideas
Use the sources-of-food topic check to connect plant needs, food demand, production methods and environmental effects.
Syllabus and review details
- SEC G1 Science 2027 · 2027
Content structure and syllabus content, PDF pages 8–17
Last reviewed: