Food Production

Question 1

How do greenhouses work

Answer 1

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

Question 2

What is hydroponics

Answer 2

Plants grown in hydroponic culture not soil to provide exactly the right balance of mineral ions for specific crop to grow

Question 3

How do polythene tunnels work

Answer 3

Protect crops from effects of weather like wind and rain and maintain a warmer temperature

Question 4

What does increased c02 and increased temperature do

Answer 4

More photosynthesis more growth up to plutonium temperature and c02 to heat above optimum is waste of money same with CO2 concentration

Question 5

How do fertiliser increase crop yield

Answer 5

Adds extra mineral ions which can be used to make proteins and other compounds for growth

Question 6

How does irrigation ( PLOwing fields) help

Answer 6

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 .

Question 7

What does adding lime do

Answer 7

Increased soil PH which means better hotel or minerals and ions for some plants .

Question 8

How does a food calorimeter work

Answer 8

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

Question 9

What’s the equation for calorimetry

Answer 9

Mass of food. = energy In j/G

Question 10

How much does 1cm3 of water weigh

Answer 10

1g

Question 11

What’s wrong with inorganic fertilisers

Answer 11

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

Question 12

What are pests

Answer 12

Organisms that reduce yield of crop plants or stock animals causing economic damage

Question 13

How do pesticides work

Answer 13

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

Question 14

Fungicides

Answer 14

Kill fungal infections

Question 15

Insecticides

Answer 15

Kill insects that might damage crops

Question 16

Herbicides

Answer 16

Kill weeds that take away valuable water light and minerals from the crops

Question 17

What is biological control

Answer 17

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

Question 18

Why doesn’t biological control eradicate. A pest

Answer 18

Because then they would die out too as there would be no food for them to eat

Question 19

How are ladybirds used

Answer 19

As a predator to control populations of aphids in Orange groves

Question 20

How is pathogenic organism used in Australia

Answer 20

Rabbits were a pest and caused habitat loss , myxoma virus was released and was successful as it was fatal 14 days after infection

Question 21

How does crop rotation stop pests

Answer 21

Stops build of pests in a particular place as their favourite food is moved

Question 22

How does monoculture increase pests

Answer 22

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

Question 23

Why do people now farm fish

Answer 23

Meets the shortfall in fish of the worlds ocean

Question 24

How is predators fixed from fish farming

Answer 24

Use a net stops predators getting in and stops wild fish carrying diseases getting in

Question 25

How is disease stopped in fish farming

Answer 25

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

Question 26

How is food controlled in fish farming

Answer 26

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

Question 27

What is the issue with pesticides in fish farming

Answer 27

Used to kill fish paracites but can pollute the water and are often toxic to other species of invertebrates.

Question 28

How is waste controlled

Answer 28

Filtered out to stop disease spread and eutrophication

Question 29

How is oxygen controlled

Answer 29

Water is oxygenated so fish can respire and grow

Question 30

Growth hormones

Answer 30

Maximise rate of growth but can have harmful ecological problems if pollute water

Question 31

Temperature

Answer 31

Kept optimum for faster enzyme reaction so faster growth

Question 32

Mínimas competition

Answer 32

Species are kept in separate tanks and

Question 33

Selective breeding fish

Answer 33

Used to produce faster growing fish and more placid fish ( don’t move a lot )