Food Production Flashcards
Why do farmers choose to grow crops in greenhouses?
- Artificial heating
- Artificial lighting
- Additional CO2 in the air
- Regular watering
You know the reasons why farmers use greenhouses, however, how does each benefit work?
- The transparent material allows sufficient natural light in for photosynthesis during the summer. Additional lighting gives a ‘longer day’ during the winter for valuable crops.
- The greenhouse effect also raises the temperature in the glasshouses
- Burning wood or fossil fuels increase the temperature when the external temperature is too cold.
- Water vapour maintains a moist atmosphere and so reduces water loss via transpiration
What do greenhouses increase the rate of?
- Increase the rate of photosynthesis
What are the two types of fertiliser?
- Organic
- Inorganic
What is an organic fertiliser made from?
- Made from the faeces of a range of animals
What is inorganic fertiliser made from?
- Inorganic compounds
What are the advantages and disadvantages of Organic fertilisers?
- Advantages:
- Improves soil structure
- Greater range of minerals
- Less cost to farmers
- Releases minerals over a longer period of time
- Disadvantages:
- Slow acting
- Harder to apply than inorganic fertilisers as it is bulkier
- May contains pests
What are the advantages and disadvantages of inorganic fertilisers?
- Advantages:
- Mineral ions released immediately so fast acting
- Contents are known
- Easy to apply
- Disadvantages:
- Can lead to eutrophication as fertiliser is soluble
- Requires regular reapplication
What is nitrogen used for in plants?
- Making proteins
What are pests?
- Pests are organisms which reduce crop yield
How can we control pests?
- Chemicals called pesticides
- Biological control (using other organisms to reduce numbers of pests)
What are the four types of pesticides?
- Herbicides (kill plant pests)
- Insecticides (kill insects)
- Fungicides (kill fungi)
- Molluscicides (kill molluscs)
What is a problem with Biological control?
- It never eradicates the pest it only reduces the number of pests in a given area.
What are the methods of biological control?
- Introduce a natural predator
- Introduce a herbivore
- Introduce a parasite
- Introduce a pathogenic microorganism
- Introduce sterile males
- Using pheromones
What are the advantages and disadvantages of pesticides?
- Advantages:
- Reduces pest population instantly
- Can kill the whole population of pests
- Disadvantage:
- Expensive as you need regular application
- Pest can become resistant to chemical
- Not specific (will kill other insects as well as the pest)
- Chemical can concentrate on all organisms higher up the food chain
What are the advantages and disadvantages of biological control?
- Advantages:
- Organisms only introduced once as it will reproduce
- Only one cost for the initial introduction
- Pest-specific (only kills pests)
- Pest will not become resistant
- No effect on other animals in the food chain
- Disadvantages:
- Takes time to reduce pest
- Not all population killed
- Expensive if re-populating is required
How can you make the perfect fish farm?
- Feed them protein and lipid-rich food as well as regular feeding with small amounts.
- Prevent predation by putting a net over the pond
- Remove waste so disease doesn’t spread
(remove dead fish) - Intraspecific competition can be prevented by placing different species in different ponds so that they don’t compete for food
- Antibiotics to stop a disease
- Selective breeding
What happens if many individuals are in your fish farm and how can these problems be solved?
- Intraspecific competition: Larger individuals will outcompete the smaller ones
- Infectious disease: Pathogens spread quickly
- Solve these problems by separating fish by age and size. Remove dead or infected fish quickly. Add antibiotics to the water to kill bacteria
What can fish farms do to the environment?
- Excess feed and waste from fish can cause eutrophication and a reduction in oxygen concentrations in the water
State the process of Eutrophication
- Nitrates and Phosphates are put onto fields as fertilisers
- Rain washes these fertilisers into rivers and lakes
- Extra nutrients cause algae to grow fast and block out light (algal bloom)
- Plants can’t photosynthesise and start to die
- Microorganisms that feed on dead plants increase in number and use up all the oxygen in the water
- The fish that need oxygen die
How does Sewage cause Eutrophication?
- Sewage contains lots of phosphates from detergents
- It also contains nitrates from urine and faeces
- When this gets washed into the river the same process of eutrophication occurs
How is yogurt produced?
- Fermentation of milk
- Milk is pasturised (heated)
- Then cooled
- Lactobacillius bacteria are added and mixture is incubated in a fermenter
- This forms lactic acid
- This causes yogurt to thicken
- Add fruit
What is the medium used in fermenters for growth?
- Culture medium
What level must the pH and temperature be kept at?
- Optimum temp and pH
How do we make sure no pathogens enter fermenter?
- Sterelise it with super heated steam that kills unwanted microbes
Why are there paddles on fermenter?
- Can always access the nutrients needed for growth
