Food Production (AQA GCSE Biology): Revision Notes
Farming techniques
What is intensive farming?
Intensive farming is a method that farmers use to produce more food from their land. It's sometimes called factory farming. The main goal is to get as much food as possible while using less space and resources.
In intensive farming, farmers control almost everything about how animals live. This helps animals grow faster and produce more food for humans.
The key principle behind intensive farming is maximising food output per unit of land by carefully controlling the animals' environment and reducing energy waste.
How intensive farming works
Intensive farming uses several key methods to increase food production:
Restricting animal movement
- Animals are kept in pens or cages so they can't move around much
- This stops them from using energy to walk, run, or play
- Less energy spent on movement means more energy goes into growing bigger
Controlling the environment
- Buildings are kept warm using heaters
- Animals don't need to use their own energy to stay warm
- This saved energy helps them grow faster instead
Special diets
- Animals get food that's high in protein
- Protein helps animals build muscle and grow quickly
- The food is carefully planned to give maximum growth
Why does this increase food production?
When animals use less energy moving around and staying warm, they can put that energy into growing bigger and faster. Think of it like this - if you didn't have to walk to school every day, you'd have more energy left for other activities.
Potential Problems with Intensive Farming:
However, there are some downsides:
- Animals can become stressed from being confined
- They're more likely to get ill when kept close together
- Heating costs money and uses electricity
- Some people think it's unfair to keep animals this way
Comparing free-range and intensive farming
Free-range chickens:
- Can move around freely and flap their wings
- Behave naturally (scratching, pecking)
- Grow more slowly because they use energy moving
- Usually cost more to buy
- Many people think this is more ethical
Intensive chickens:
- Kept in heated barns with little space
- Grow faster and get bigger
- Cost less to produce and buy
- Use less energy on movement, so more goes into growth
Plant diet vs animal diet
Eating plants directly is much more energy efficient than eating meat from animals. Here's why:
Energy loss in food chains
When we eat meat, energy gets lost at each step:
- Plants capture energy from the sun
- Animals eat the plants but lose lots of energy moving around, staying warm, and breathing
- Humans eat the animals but only get the energy that's left
Direct plant consumption
When we eat plants directly:
- Plants capture energy from the sun
- Humans eat the plants and get much more of the original energy
Example: Energy Efficiency Comparison
This means the same amount of farmland can feed more people if we grow plants for humans rather than growing plants to feed animals that we then eat.
If 1 hectare of land produces enough plants to feed 10 people directly, the same land might only feed 2-3 people if those plants are fed to animals first, then the animals are eaten by humans.
Biomass and food chains
Biomass means the total mass of living things at each level of a food chain. As energy moves up the food chain, biomass gets smaller at each level.
Example: Ocean Food Chain
For example: microscopic plankton → sardines → tuna
- There's much more plankton than sardines
- There's much more sardines than tuna
- This is because energy is lost at each step
That's why it's more efficient to eat sardines than tuna - the sardines are closer to the bottom of the food chain, so less energy has been lost.
Key Points to Remember:
- Intensive farming increases food production by restricting animal movement and controlling their environment
- Animals use less energy on movement and staying warm, so more energy goes into growing bigger
- Eating plants directly is more energy efficient than eating meat
- Biomass decreases at each level of a food chain due to energy loss
- There are benefits and drawbacks to intensive farming methods