Food production
At each stage in the food chain more and more energy is lost from the biomass (dry mass) of an organism.
In GCSE Biology curriculum, energy loss from plants:
- For respiration
- Not all of the light energy hits the chloroplasts (i.e, some light passes through the air spaces)
- Plants can't use the wavelength for green light, so it is reflected off the surface of the leaf.
Energy loss from animals:
- For respiration
- Movement
- Heat (in mammals)
- Excretion of waste
So, it is more efficient to produce food from plants (rather than animals) because they are at the beginning of the food chain.
Usually in GCSE Biology, food production can be made more efficient by...
- Reducing the number of stages in the food chain
- Restricting the energy loss by livestock i.e, by keeping animals indoors to reduce the amount of energy needed to keep themselves warm and to restrict their energy loss from movement
Consumers are becoming more concerned about the environmental, economic and ethical implications on how we produce our food.
Intensive farming
Some livestock are intensively farmed. This involves animals such as chickens and pigs being housed close together in indoor pens.
Advantages of intensive farming:
- Accommodation is cheap and secure from predators e.g, foxes
- Environmental conditions can be controlled
- Energy isn't wasted on movement or heat, making energy transfer more efficient
- Cheap product for the farmer to sell
Disadvantages of intensive farming:
- Disease can spread quickly in crowed conditions, which can mean that expensive antibiotics have to be bought at the cost of the farmer.
- Behaviour of animals causes them to fight, which can lead some animals injured or even dead
- Some people consider intensive farming to be cruel
Fossil fuels
In GCSE Biology, fossil fuels are used to maintain environmental conditions (e.g. To heat heaters and lights) which contributes to global warming (the larger an animal is (e.g, a sheep is larger than a chicken) the worse the environmental consequences because they will take longer to grow before they are killed for meat, so more fossil fuels will be used)
End of this topic!
Drafted by Gina (Biology)