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Modern farming techniques and efficiency

EcologyFood production (biology only)

Flashcards

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Explain how high-protein feed improves growth in farmed fish.

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High-protein diets supply amino acids needed for tissue synthesis so a higher fraction of consumed energy becomes fish biomass, increasing growth rates .

Key concepts

What you'll likely be quizzed about

Definition: intensive farming and monoculture

Intensive farming uses machines, chemicals and housing to maximise yield from crops or livestock. Intensive animal farming keeps larger numbers of animals in smaller spaces and often limits movement to reduce energy loss, increasing the proportion of food energy converted to biomass . Monoculture means growing the same crop on the same land repeatedly. Monoculture increases harvesting efficiency and allows mechanisation but causes soil nutrient depletion and increases pest build-up because of the continuous availability of a single host species .

Energy flow and efficiency in food production

Producers (plants and algae) capture only a small fraction of the Sun’s energy, typically around 1%, which limits the available energy for higher trophic levels . At each trophic transfer roughly 10% of biomass (and thus energy) becomes consumer tissue; the remainder is lost as faeces, urine and by respiration (heat) . Energy losses by respiration increase when animals move more, when internal temperatures require more metabolic heat production, or when animals fight disease. Reducing those losses increases the proportion of energy converted into edible biomass.

Techniques that restrict energy transfer from animals

Restricting movement by housing animals in smaller pens reduces activity-related respiration and so reduces energy loss, increasing growth for the same feed input . High-protein diets and close control of feeding increase the fraction of dietary energy turned into tissue rather than being lost as waste. Temperature control in housing reduces energy spent maintaining body temperature. Intensive fish farms feed high-protein diets to stock in cages to maximise growth rate and feed conversion efficiency .

Selective breeding, biotechnology and veterinary care

Selective breeding chooses animals with high growth rates and improved feed conversion ratio, so less resource input produces more biomass. Biotechnology and controlled fermentation produce alternative protein sources (for example mycoprotein), reducing pressure on livestock production. Regular veterinary care and use of medicines reduces illness-related energy loss and mortality, increasing overall yield, but antibiotic use has a risk of promoting resistant bacteria and presents an ecological trade-off .

Environmental and ethical limiting factors

Removal of hedgerows and intensive monoculture increase the scale at which machines operate but reduce biodiversity and habitat connectivity, harming ecosystems . Soil nutrient depletion limits long-term yields unless fertilisers are used; fertiliser use increases yields but can cause runoff and pollution. Ethical concerns arise from housing conditions in factory farming and from genetic modification debates, which influence public acceptance and regulation .

Key notes

Important points to keep in mind

Producers capture only ~1% of incoming light energy; this limits all food production .

Only about 10% of biomass transfers between trophic levels; removing trophic levels increases efficiency .

Restricting animal movement reduces activity-related respiration and increases feed-to-biomass conversion .

Monoculture increases mechanisation benefits but increases pest risk and soil depletion .

Selective breeding and controlled feeding improve feed conversion ratio but raise ethical and disease-management issues fileciteturn0file16turn0file14.

Antibiotic use in feed increases yield short term but can accelerate antibiotic resistance .

Crop rotation and hedgerow retention support soil health and biodiversity, limiting long-term declines in yield .

Alternative proteins (e.g., mycoprotein) offer lower-land, lower-energy routes to human nutrition under controlled fermentation .

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