5.9 fish farming

explain the methods which are used to farm large numbers of fish to provide a source of protein, including maintenance of water quality, control of intraspecific and interspecific predation, control of disease, removal of waste product, quality of frequency of feeding and the use of selective breeding. 


fish is an attractive product for farmers:
-fish has low fat and high protein
-fish is efficient in turning nutrients into fish mass.

PROS-
-fish farming will allow us to control the quality of water (clean)
-control predators.
-reduce pests and diseases.
-all of these contribute in an increase in yield of fish.

CONS-
-if high density- transmission of diseases. so some farmers use antibiotics- bad for human health.
-abundance of fish makes pests common and therefore some farmers will use pesticides- also a concern for humans.

5.8 Fermenter

interpret and label a diagram of an industrial fermenter and explain the need to provide suitable conditions in the fermenter, including aseptic precautions, nutrients, optimum temperature and PH, oxygenation and agitation for growth of microorganisms.


-built with some kind of metal (copper, steel)
-steam cleans the fermenter between fermentations.
-heater and water jacket controls the optimum conditions for fermentation.

5.7 Yoghurt

understand the role of bacteria (Lactobacillus) in the production of yoghurt


-start with the milk from the cow.
-milk needs to be treated to remove pathogens such as TB bacillus (process called pasteurisation) heat treatment.
-milk sugar is converted into lactic acid. (incubating the milk at 45-46 degrees c) and add the lactobacillus.
-lactobacillus produce the enzymes which are going to break the milk sugar lactose and this will produce lactic acid.
-the acid will result in a low PH. acidic conditions causes the milk protein to solidify. solidification of milk product is yoghurt.

5.5 beer production

understand the role of yeast in the production of beer.


-beer is largely ethanol (an alcohol molecule) and this is produced form glucose and it is broken down into CO2 and ethanol (anaerobic respiration) sometimes called fermentation respiration.
-the microorganism that does this is yeast. yeast is able to supply the enzyme to bring about the conversion. that is where the alcohol in beer comes from.
-the ethanol is flavoured by the plants such as hops to change the flavour.
-the glucose comes from starch. starch ---amylase---> maltose --maltase--> glucose
-starch comes from (sources) barley seeds, wheat seeds, rice (beers in asia)
-starch is broken into amylase by the process of malting. (germination of seeds)

5.4b Biological control

understand the reasons for pest control and the advantages and disadvantages of using biological control with crop plants.


an example of controlling a pest (plant) by a herbivore (moth) called biological control - not using pesticides.

-in australia the prickly pair cactus of north america was introduced into gardens. the cactus started to cover agricultural land so it was necessary to get rid of it. there was no natural predator of the cactus so an alien species of another country had to be introduced. moth -> feeds on the cactus. (cactoblastis) =
-moth was introduced and there was no competitors so it was able to eat away the cactus and remove it away from agricultural land.

PROS-
-no toxic chemicals involved
-less impact on humans and wildlife.

CONS-
-not 100 percent effective.
-difficult to control. -always a danger. the species might find alternative prey to feed and will not die out. (eg. famous- cane toad in australia)
-difficult to match a predator to the prey. (cannot find suitable predator to remove pest)

5.4a Pesticides

understand the reasons for pest control and the advantages and disadvantages of using pesticides.
-where there is a large field of crops all of the same type- monoculture (eg fields barley, wheat, rice)
-where there is monoculture they tend to be susceptible to pests. (variety of living things -> use crop as food source --> reduce productivity of farming -> lose of food and financial impact on farmer)
-to overcome this is to use pesticides -> chemicals -> designed to kill pests.

PROS
-chemicals -> easy to obtain.
-easy to apply
-they are very effective

-CONS-
-many of the chemicals are toxic. will kill other plants and animals and harmful to humans
-biro accumulation -> pesticides build up through the food chain causing problems for animals in the higher tropic levels (DDT)
-mutation in the pest -> resistance to chemicals.   -> stronger chemical used which will be harmful to humans or the chemicals might not work so a new chemical would need to be used.

5.3 Fertilisers

understand the use of fertiliser to increase crop yield

-growth of plants is achieved by fertilizers to the soil.
-fertilizers take the form of nitrates and phosphate. or sometimes both
-compounds go down into the soil and taken up in the root structure and then moved into the transpiration stream up to the leaf and used in the leaf for the construction eg. nitrate form protein and phosphate- DNA and membrane structure.
-fertilizers can be divided into 2 groups.
-organic and artificial.

-organic is produced by animal waste on farms. (cow faeces)
-then grows through the process of decomposition and fermentation.
-forms a compound/substance called slurry. this is applied to the fields giving a supply of nitrate and phosphate for growth of crops.

-artificial takes the form of chemicals which is synthetically produced.
-potassium nitrate and ammonium nitrate (solution). this can be brought by the farmer.
-will release the nitrates. (solution into the soil water)

-will promote growth same way as the organic one.

5.2 Crop Yield.

understand the effects on crop yield of increased carbon dioxide and increased temperature in glasshouses.


-related to the rate of photosynthesis. combination of carbon dioxide and water ---sunlight (enzyme reaction) --> glucose and oxygen.
-glucose is turned into starch and is stored in the plant.

-increasing carbon dioxide. CO2 is the substrate.
-rate of reaction (photosynthesis) will increase if we increase the carbon dioxide level until a certain point
-will produce a higher yield up to a point until maximum yield.

-increase the temperature.
-rate of photosynthesis and temperature graph.
-increase in temperature the rate of photosynthesis will increase --> yield will increase.
-when we hit the peak on graph -> optimum temperature.

-increase carbon dioxide and increase in temperature there will be an increase in photosynthesis therefore the yield but they both have limits.

-increasing temp in a greenhouse will have other affects such as avoiding frost damage and providing constant temperature - contribute to increased yield.

5.1 Glasshouses

describe how glasshouses and polythene tunnels can be used to increase the yields of certain crops.

-in some countries known as greenhouses.
-simple house structure but all surfaces are glass allowing light to enter.
-the polythene tunnels usually a frame work with polythene. allows light to enter- cheaper that glass house somewhat ajustable can be taken down and replaced. (used in less developed countries)

-solar radiation -> source of energy -> in the form of light.
-light is able to penetrate through the glass to the internal surfaces.
-the light is absorbed by surfaces inside the glass house. (soil, plants, whatever is in the glass house)
-the surfaces will reemit the energy as heat.
-heat warms the air and raising the average kinetic energy -> the temperature increases.
-the warm air which is raising the temperature is trapped (it would cool at the upper surfaces and sink to the floor again to be rewarmed by the surfaces within the glasshouse)

how does this cause an increase the crop yield?
-warm air in glass house -> increase in crop yield.
1: - higher temperature in glass house causes a closer optimum temperature for enzyme reactions (includes photosynthesis)
2: - it provides constant temperature through out the growing year- constant production.
3: - the prevention of loss of water vapour. crops don't dry out. constant supply of water. water vapour doesn't escape to atmosphere.
4: - avoid frost damage- seedlings in the spring time.
5: - glass house is often warmed by burning of fossil fuels
a) increase in CO2 - increased concentration of substrate for photosynthesis. more product and more growth.
b) inefficient burning of fossil fuels leads to the production of ethene. -> this stimulates fruit ripening (particularly in the tomato)