5. Use Of Biological Resources Flashcards
What are the factors that effect photosynthesis !?
Light intensity
Carbon dioxide concentration
Temperature
Rate of photosynthesis + light intensity graph:
Rate of photosynthesis + **carbon dioxide concentration ** graph:
Rate of photosynthesis + temperature graph:
Why do farmers choose to grow crops in greenhouses?
In open fields, it is very difficult to control the factors that affect the rate of photosynthesis within greenhouses farmers can have control over these factors
What can farmers control within greenhouses!?
. Temp - artificial heating
. Light intensity– artificial lighting
. Carbon dioxide concentration – additional carbon dioxide in the air
. Regular watering
What do greenhouses and polythene tunnels provide for plants !?
Greenhouses and polythene tunnels, provide enhanced conditions for plants to grow
How to greenhouses and polythene tunnels, provide enhanced light intensity!?
The transparent material allows sufficient natural light in the photosynthesis during the summer
Artificial lighting gives a “longer day” during the winter for valuable crops.
How to greenhouses and polythene tunnels, provide enhanced temperature!?
The greenhouse effect also raises the temperature in glasshouses
Burning fossil fuels or wood raises the temperature when the external temperature is too low. It also produces carbon dioxide and water vapour
Why is water vapour important in greenhouses and polythene tunnels? 
Water vapour maintains a moist atmosphere, so reduces water loss by transpiration
What must the farmer find in order to make sure that the additional cost of providing conditions are weighed against the extra profit provided by the increased yield !?
Define almost find the optimum conditions
How do nitrates increase crop yield !?
Nitrates are needed for proteins
How does magnesium increase crop yield !?
Magnesium is needed for the production of chlorophyll
What is organic fertiliser made from!?
Organic fertiliser is made up from the faces of a range of animals, sometimes mix with straw.
Also compost from legumes such as clover.
What is inorganic fertiliser made from!?
Inorganic fertiliser is composed of inorganic compounds carefully formulated to yield a specific concentration of a particular ion when applied according to the manufacturer’s instructions
What are the advantages of organic fertiliser?
Improves soil structure
Greater range of minerals
Release is minerals over a longer period of time
Less cost a farmer (already available on the farm)
What are the disadvantages of organic fertiliser?
Slow acting- has to be decomposed first
Bulkier, so more difficult than inorganic fertilisers to apply
May contain pests
What are the advantages of inorganic fertiliser?
Mineral ions are released immediately so fast acting
Contents known
Easy to apply
What are the disadvantages of inorganic fertiliser?
Can lead to eutrophication as fertiliser is soluble
Requires regular Reapplication
What is another way, bar fertiliser, to replace lost nitrates in fields !?
Another way to replace lost nitrate is to grow a a legume crop, such as clover, in a field one year in four
Why areleguminous plants a good way to replace lost nitrates in fields !?
These plants have nitrogen-fixing bacteria in nodules on their roots. They convert nitrogen gas in the air into ammonium ions.
This is passed to the plants which use it to make proteins
What happens after the leguminous crop is ploughed in?
When the crop is ploughed in and the protein in the crop and bacteria is broken down (decomposed) ammonium is released into the soil.
This ammonium is in converted to nitrate by nitrifying bacteria and is a level for the next years crops.
