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gcse science B4 - F
specific for ocr gateway additonal science B.
| Question | Answer |
|---|---|
| what is intensive farming? | producing as much food as possible in the space available. |
| what is used in intensive farming? | pesticides, herbicides, fungicides, fertilizers |
| what is a disadvantage of intensive farming? | -raises ethical issues such as cruelty to animals -environmental concerns as the pesticides can pollute the land |
| what is an advantage of intensive farming? | extremely efficient as more energy is usefully transferred |
| why is intensive farming so efficient? | -there are fewer weeds and pests in crops -animals are kept in sheds meaning there is less heat loss and their movement is restricted - so less energy loss |
| how do pesticides affect food chains? | concentration of the pesticide increases with the trophic levels, eventually killing some organisms |
| how do pesticides build up to lethal doses in food chains? | they get into lakes from farmlands and build up in different organisms |
| what does hydroponics mean? | growing something without using soil |
| what can hydroponics be used to grow? | lettuce and tomato plants |
| why does an air pump deliver air bubbles containing oxygen to the plant roots? | plant needs oxygen to respire, so then roots produce energy to use active transport to get minerals into the plant |
| what are some advantages of using a hydroponics system? | -unused minerals are recycled, reducing cost -set up under cover so there's better control of conditions and disease -fewer weeds and reduced need for pesticides and herbicides |
| what are some disadvantages of using a hydroponics system? | -manufactured fertilizers must be bought, which are expensive -tall plants such as tomatoes need support |
| where is hydroponics a good idea? | in countries with poor soil or little water to irrigate fields |
| what is organic farming? | producing food using natural sources of nutrients |
| what are manure and compost used for? | natural source of fertiliser |
| what happens to weeds? | hand-removed to reduce competition for light and minerals |
| why are seeds sown at different times? | so crops are ready throughout the year |
| what are nitrogen-fixing plants used for? | to put nitrogen back in the soil, e.g. beans |
| why is crop rotation used? | so that the same crops don't grow in the same place each year and use up all of the minerals in the soil |
| what is used instead of pesticides to kill pests? | other animals, such as ladybirds that eat aphids. |
| what is an advantage of using animals instead of pesticides? | saves the use of chemicals which damage the environment |
| what is a disadvantage of using animals instead of pesticides? | very slow to work and takes animals out of a food chain |
| where is organic farming a good idea? | in countries that aren't short of food |
| why do people want organic food? | -seen to be healthier -people can afford to pay more |
Created by:
jirwin
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