carbon cycle Flashcards
(14 cards)
What is the carbon cycle ?
The carbon cycle is a nutrient cycle that shows how carbon is passed from the atmosphere (where it is in the form of carbon dioxide) into plants (during photosynthesis) and on to animals as they feed on plants.
Significance of photosynthesis in carbon cycle
photosynthesis: plants absorb carbon, in the form of carbon dioxide, from the atmosphere during photosynthesis.
- Plants then use this carbon dioxide (combined with water) to form carbohydrates like starch
Significance of respiration in carbon cycle
respiration: all organisms respire. This process uses the carbohydrates (such as glucose) and produces carbon dioxide. This carbon dioxide is released back into the atmosphere. Remember that plants, animals and the decomposers all respire.
Significance of combustion in carbon cycle
combustion: this is burning, when any fuel (coal, oil, gas, wood) is burnt it releases carbon in the form of carbon dioxide back into the atmosphere.
Significance of decomposition in carbon cycle
decomposition: this process breaks down any dead or decaying matter ensuring that the carbon contained within these molecules is released back into the atmosphere as carbon dioxide or released as minerals into the soil.
Significance of fossilisation in carbon cycle
fossilisation: under certain circumstances (e.g. when it is very cold or there’s a lack of oxygen) dead organisms do not become fully decomposed. Over millions of years these partially decomposed materials are converted into fossil fuels such as coal, oil and gas.
Significance of feeding in carbon cycle
feeding: as described on our work on food chains, plants are producers which are then consumed by animals. When this occurs the carbon in the biomolecules in the plants are passed into the animals
Explain how environmental changes affect the distribution of organisms (3)
Deforestation causes there to be fewer plants to absorb carbon dioxide during photosynthesis and loss of habitats for animals.
Melting ice caps leads to increased sea levels which disrupts sea life
Rapid global warming means certain species’ do not have time to adapt to different climates
photosynthesis, respiration,combustion word equation
p= carbon dioxide + water——— glucose + oxygen
R= glucose +oxygen————- carbon dioxide + water
C= fossil fuel or wood + oxygen———- carbon dioxide + water
How is carbon taken out of the atmosphere?
Carbon is taken out of the atmosphere in the form of carbon dioxide by plants during photosynthesis.
How is carbon returned to the atmosphere in the carbon cycle?
Carbon is returned to the atmosphere when it is released as carbon dioxide by the following processes:
Respiration in plants and animals
Respiration of decomposers, e.g. bacteria
Combustion of fossil fuels or other organic matter, e.g. wood
Reversal of the dissolving process by which carbon dioxide dissolves in the oceans
describe the carbon cycle
- plants fix carbon dioxide into organic molecules during photosynthesis
-The organic carbon- containing molecules are passed onto organisms that eat the plants
-carbon dioxide is released back into the atmosphere by respiration from plants and animals.
- burning fossil fuels releases carbon dioxide into the atmosphere.
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why is the carbon cycle important
carbon-containing molecules such as glucose are important for living organisms to grow and provide energy for vital functions within cells
What is the impact of mass deforestation on the carbon cycle?
Mass deforestation (cutting down many trees) affects the carbon cycle as follows:
It reduces the number of trees carrying out photosynthesis so less carbon is removed from the atmosphere
It is often followed by combustion as trees are burned, increasing the addition of carbon to the atmosphere
