Food Production + Selective breeding

What factors can be maintained in a glasshouse

• Heat- Artificial heating

• Light- Lightbulbs

• CO₂ levels- Combustion of natural gas

• Water levels- Regular watering

• Humidity- High humidity can lead to breeding of fungus and bacteria

How else can crop yield be increased

• Fertilisers

• Controlling pests- Pesticides

Organic fertiliser

• Manure mixed with straw

• Can be inneficient- no control of the exact content of minerals

• Environmentally friendly

Inorganic fertiliser

• Formulated chemicals from potassium, phosphorus, nitrate, and ammonia.

• Bad for the environment- likely to lead to eutrophication (water pollution)

• Applied to the soil as dry granules or sprayed.

Pests

Any organism that reduces the yield of a farmer’s crop/livestock inc. plants/animals/microbes

Increasing temperature as an effect on phototsynthesis

• Photosynthesis rate will initially increase.

• Enzymes will gain kinetic energy since up untill they reach their optimum temperature

• Once beyond the optimum, the photosynthesis rate will decrease as the enzymes will denature

Light intensity as an effect on photosynthesis

• More light leads to more photosynthesis

• This will continue until another factor is in short supply

CO2 levels as an effect on photosynthesis

• More CO2 leads to more photosynthesis

• This will continue until another factor is in short supply

Purpose of fertilisers

• Fertilizers provide mineral ions to increase crop yield

3 main mineral ions needed for plant growth

• Potassium

• Nitrogen

• Phosphorus

Lack of nitrogen

Weak growth and yellowing of the leaves of plants

Lack of phosphorous

Poor root growth and discoloured leaves

Lack of potassium

Poor growth of flowers and fruits, as well as brown spots on leaves

Advantages of using pesticides

• Easilly accessible and relatively cheap

• Has an immediate effect

• Kills the entire population of pests

Disadvantages of pesticides

• Organisms can devlop resistance

• They’re non-specific and can kill beneficial organisms (e.g. bees)

• Need to be repeatedly applied

Biological control

When a predator is introduced to eat the pest species

Advantages of biological control

• Natural method

• No resistance

• Can be specific

• Long lasting

• Does not need to be repeatedly applied

Disadvantages of biological control

• Takes time to be effective

• Cannot kill the entire population

• May not adapt to the area

• May eat other organisms

Yeast in the process of making bread

• Yeast is added to the dough

• The yeast will produce enzymes that break down the starch in flour. releasing sugars that can be used by the yeast in respiration

• The yeast will initially respire aerobically but will switch to anaerobic when oxygen runs out.

• The yeast will then produce ethanol when switched to anaerobic respiration

• The CO2 produced by the yeast will create small air pockets in the dough, causing it to rise.

• During baking, the ethanol evaporates and the yeast is killed.

Anaerobic respiration in yeast equation

• Glucose → Ethanol + Carbon Dioxide

• C₆H₁₂O₆ → 2C₂H₅OH + 2CO₂

Fermentation

Anaerobic respiration in yeast

CORMS analysis for investigating anaerobic respiration in yeast

• C- We will be changing the temperature of the water bath to see its effect on anaerobic respiration

• O- We will use the same type of yeast.

• R- We will repeat the investigation 3 times at each temperature to increase reliability

• M- We will measure the bubbles of carbon dioxide produced in 2 minutes which will be timed using a stopwatch.

• S- We will keep the concentration and volume of the sugar solution the same

Bacteria needed to make yogurt

Lactobaccilus

Yogurt making process

1. All equipment is sterilized. This is done by pumping steam at high pressure. This will prevent contamination.

2. Milk is then pasteurized by heating (80-85°c) . This kills any unwanted bacteria.

3. The milk is now cooled to 40- 45°c and lactobacillus bacteria are added.

4. The mixture is incubated and the lactobacillus bacteria digests the milk proteins and ferment the sugar.

5. The lactobacillus bacteria converts the lactose into lactic acid. This thickens and increases the acidity of the milk and forms yogurt.

6. The yogurt is cooled to 5°c. This will kill the lactobacillus bacteria.

7. Flavourings, fruit and colourants are added before the packaging process.

Advantage of using an industrial fermenter

 Conditions can be carefully controlled to produce large quantities of exactly the right type of microorganism

Benefits of fish farming

• Selectively breed fish which are fast growing, and high quality.

• Protection against predators

• Water quality and feeding is controlled

How is water quality maintained in fish farming

• Filtered to remove harmful bacteria and waste

• Cleaned regularly to maintain high levels of oxygen for aerobic respiration

Intraspecific predation

• Predation within the same species

• Fish are separated by age and size

Interspecific predation

• Predation between different species

• Different species of fish are separated by tanks, nets, and tanks

How is disease controlled in fish farming

• Antibiotics are given to fish

• Dead fish are removed immediately to prevent disease from spreading

Optimised diet in fish farming

• Fish are fed a high protein diet regularly up to 24hrs a day

• Pellets are made of smaller fish- decrease in wild fish species

What factors are maintained in the fish tank

• Oxygen levels

• pH levels

• Temperature

Selective breeding in fish farming

• Fast breeding, healthy, large fish are selected and chosen to breed together.

• After a few generations, the ideal fish is produced- maximising profits

Selective breeding

Breeding 2 organisms that have desirable characteristics

Why are animals selectively bred

• Higher yield

• More resistant to disease and pests

• To produce greater quantity of offspring

How are animals selectively bred

Artificial insemination

Process of selective breeding

1. Organisms with desired characteristics chosen
2. These are bred together
3. The offspring showing the desired characteristics are
selected and bred together
4. This is carried out over many generations

Why are plants selectively bred

• Disease resistance in food crops

• Increased crop yield

• Hardiness to weather conditions

Problems with selective breeding

• Inbreeding: Reduction in gene pool- reduction of alleles in a population

• Inheriting genetic defects

• Vulnerable to diseases