Food Production Flashcards
How do greenhouses work
Transparent material allows sufficient natural light in for photosynthesis during summer and additional lighting gives longer day in winter , short wave radiation enetering the greenhouse becomes long wave radiation as it reflects off surfaces , the long wave radiation can’t leave easily and the greenhouse heats up. Field can also be burn too raise temp when external temp is too low . Burning also produces carbon dioxide and water vapour which maintkns a moist atmosphere and reduces water loss by transpiration and CO2 is needed for photosynthesis
What is hydroponics
Plants grown in hydroponic culture not soil to provide exactly the right balance of mineral ions for specific crop to grow
How do polythene tunnels work
Protect crops from effects of weather like wind and rain and maintain a warmer temperature
What does increased c02 and increased temperature do
More photosynthesis more growth up to plutonium temperature and c02 to heat above optimum is waste of money same with CO2 concentration
How do fertiliser increase crop yield
Adds extra mineral ions which can be used to make proteins and other compounds for growth
How does irrigation ( PLOwing fields) help
Breaks up compacted soil adds manure to improve drainage and aeration of heavy clay soil as good aeration and drainage allow better uptake of mineral ions and water and if a plant is wilting the photosynthesis rate decreases .
What does adding lime do
Increased soil PH which means better hotel or minerals and ions for some plants .
How does a food calorimeter work
A heating filament carrying electrical current ignites the food and te calorimeter is filled with oxygen so the food burns easily . There is coil to transfer heat from the burning food to water and a stirrer to distribute food and a heat proof mat so no heat is lost to the platform or you can burn food held on a mounted needle under 20cm3 of water in a test tube
What’s the equation for calorimetry
Mass of food. = energy In j/G
How much does 1cm3 of water weigh
1g
What’s wrong with inorganic fertilisers
Replaces all lost ions unlike organic which only replaces some lost ions but leads to eutrophication and can damage soil structure as it does not replace organic matter lost to soils
What are pests
Organisms that reduce yield of crop plants or stock animals causing economic damage
How do pesticides work
Chemicals farmers use to kill specific pests to increase the yield . But mutation and natural selection can cause pests to become resistant to the pesticide making it uselsss and another pesticide must be used they can also cause environmental damage and can persist in the soil and be taken up in the food chain some are toxic
Fungicides
Kill fungal infections
Insecticides
Kill insects that might damage crops
Herbicides
Kill weeds that take away valuable water light and minerals from the crops
What is biological control
Uses another organism rather than chemical to reduce number of pests but it never eradicates a pest but reduces pest numbers to a level where they no longer cause significant economic damage
Why doesn’t biological control eradicate. A pest
Because then they would die out too as there would be no food for them to eat
How are ladybirds used
As a predator to control populations of aphids in Orange groves
How is pathogenic organism used in Australia
Rabbits were a pest and caused habitat loss , myxoma virus was released and was successful as it was fatal 14 days after infection
How does crop rotation stop pests
Stops build of pests in a particular place as their favourite food is moved
How does monoculture increase pests
Makes effective harvesting but very efficient for spread of pests as there is millions of crop plants for the Pest to spread pests can lie dormant in soil over winter causing pest damage as soon as the crop is planted
Why do people now farm fish
Meets the shortfall in fish of the worlds ocean
How is predators fixed from fish farming
Use a net stops predators getting in and stops wild fish carrying diseases getting in
How is disease stopped in fish farming
Fish are very close together so Antibiotics used which kills the bacteria but is problematic because antibiotics might not have degraded by the time te fish are eaten by humans
How is food controlled in fish farming
Fish are fed little and often too stop food sinking to the bottom and causing eutrophication but fish are carnivorous and are fed with wild fish that are less marketable species like herring decreasing wild fish stocks
What is the issue with pesticides in fish farming
Used to kill fish paracites but can pollute the water and are often toxic to other species of invertebrates.
How is waste controlled
Filtered out to stop disease spread and eutrophication
How is oxygen controlled
Water is oxygenated so fish can respire and grow
Growth hormones
Maximise rate of growth but can have harmful ecological problems if pollute water
Temperature
Kept optimum for faster enzyme reaction so faster growth
Mínimas competition
Species are kept in separate tanks and
Selective breeding fish
Used to produce faster growing fish and more placid fish ( don’t move a lot )
