In GCSE Science, students will look at energy and biomass in food chains. This is the last of three quizzes on that topic and it looks in particular at the carbon cycle.
It is quite possible that your body contains carbon atoms that were once breathed by a dinosaur. Or perhaps eaten by a king or queen or even excreted in dog poo. Yeuch! But how is this possible? The answer is one of the most important cycles for life - the carbon cycle. Our planet has only a limited stock of chemical elements and they are constantly being recycled in different ways. If they weren't, they would all have been used up long ago and the Earth would be an unchanging dead planet.
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When looking at the carbon cycle, it doesn't really matter where you start. A good place to start though is with the carbon dioxide in the air. This is absorbed by plants and used by them to produce biomass. The carbon in the plants then enters into food chains. When a plant is eaten by an animal, the carbon is passed on. The animal may use the carbon from the plant to make its own biomass, in which case it will be locked up until the animal dies. It could be used in respiration to generate energy, in which case, the carbon ends up back as carbon dioxide in the air. If the carbon is excreted as waste material, the decomposers will either release it back into the air as carbon dioxide straight away or lock it up inside their bodies as biomass.
And so it goes on, constantly being exchanged between plants, animals and the air. But food chains are not the only places where carbon is stored. It can even be locked away in rocks like limestone and chalk, only to be released millions of years later when molten magma touches them. Or it can be fossilised, as coal or oil, and released when it is burnt to generate energy.
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1.
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What process takes carbon dioxide from the air and makes it available to land living animals? |
|
[ ] |
Photosynthesis |
[ ] |
Respiration |
[ ] |
Lightning strikes |
[ ] |
Burning fossil fuels |
|
|
2.
|
Which two natural processes return carbon dioxide to the air? |
|
[ ] |
Photosynthesis and respiration |
[ ] |
Respiration and decomposition |
[ ] |
Digestion and eating |
[ ] |
Using nuclear fuels |
|
|
3.
|
Which human activity returns carbon dioxide to the air? |
|
[ ] |
Generating electricity |
[ ] |
Driving cars |
[ ] |
Flying planes |
[ ] |
All of the above |
|
|
4.
|
Why do fossil fuels have a high carbon content? |
|
[ ] |
They are made in swamps |
[ ] |
They are made from organisms that were once alive |
[ ] |
They are made from limestone |
[ ] |
They were made in fires started by lightning millions of years ago |
|
|
5.
|
Which of the following is a problem caused by humans burning fossil fuels? |
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[ ] |
A hole in the ozone layer |
[ ] |
Deforestation |
[ ] |
Global warming |
[ ] |
All of the above |
|
|
6.
|
How might burning fossil fuels be creating global warming? |
|
[ ] |
Because fossil fuels will be all used up in a few decades |
[ ] |
Because burning fossil fuels is a very dangerous process |
[ ] |
Because fossil fuels are not compatible with the new biofuels |
[ ] |
Because burning fossil fuels adds CO2 to the atmosphere faster than it can be removed |
|
|
7.
|
How is carbon in plants passed on to the rest of the cycle? |
|
[ ] |
Only death and decay |
[ ] |
Only by being eaten |
[ ] |
Through food webs |
[ ] |
By forming coal |
|
|
8.
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Carbonate rocks lock carbon out of the cycle for millions of years. Which of the following does not put CO2 from these rocks back into the current carbon cycle? |
|
[ ] |
Grinding them up into small particles to use for making roads |
[ ] |
Manufacturing cement |
[ ] |
Heat from volcanoes |
[ ] |
When they are subducted during plate tectonics |
|
|
9.
|
Why do waste materials and dead plants or animals decay? |
|
[ ] |
They are broken down by microorganisms |
[ ] |
They get rained on |
[ ] |
They slowly sink into the ground |
[ ] |
Sunlight breaks down their chemicals |
|
|
10.
|
How is the CO2 from the air introduced into a food web? |
|
[ ] |
Plants breathe it in and when an animal eats the plant, it eats the CO2 as well |
[ ] |
It forms carbonate rocks that eventually come to the surface |
[ ] |
Plants use the products of photosynthesis to manufacture carbohydrates, fats and proteins |
[ ] |
Bacteria living in nodules on the root convert it into plant food |
|
|
1.
|
What process takes carbon dioxide from the air and makes it available to land living animals? |
|
[x] |
Photosynthesis |
[ ] |
Respiration |
[ ] |
Lightning strikes |
[ ] |
Burning fossil fuels |
|
|
2.
|
Which two natural processes return carbon dioxide to the air? |
|
[ ] |
Photosynthesis and respiration |
[x] |
Respiration and decomposition |
[ ] |
Digestion and eating |
[ ] |
Using nuclear fuels |
|
|
3.
|
Which human activity returns carbon dioxide to the air? |
|
[ ] |
Generating electricity |
[ ] |
Driving cars |
[ ] |
Flying planes |
[x] |
All of the above |
|
|
4.
|
Why do fossil fuels have a high carbon content? |
|
[ ] |
They are made in swamps |
[x] |
They are made from organisms that were once alive |
[ ] |
They are made from limestone |
[ ] |
They were made in fires started by lightning millions of years ago |
|
|
5.
|
Which of the following is a problem caused by humans burning fossil fuels? |
|
[ ] |
A hole in the ozone layer |
[ ] |
Deforestation |
[x] |
Global warming |
[ ] |
All of the above |
|
|
6.
|
How might burning fossil fuels be creating global warming? |
|
[ ] |
Because fossil fuels will be all used up in a few decades |
[ ] |
Because burning fossil fuels is a very dangerous process |
[ ] |
Because fossil fuels are not compatible with the new biofuels |
[x] |
Because burning fossil fuels adds CO2 to the atmosphere faster than it can be removed |
|
|
7.
|
How is carbon in plants passed on to the rest of the cycle? |
|
[ ] |
Only death and decay |
[ ] |
Only by being eaten |
[x] |
Through food webs |
[ ] |
By forming coal |
|
|
8.
|
Carbonate rocks lock carbon out of the cycle for millions of years. Which of the following does not put CO2 from these rocks back into the current carbon cycle? |
|
[x] |
Grinding them up into small particles to use for making roads |
[ ] |
Manufacturing cement |
[ ] |
Heat from volcanoes |
[ ] |
When they are subducted during plate tectonics |
|
|
9.
|
Why do waste materials and dead plants or animals decay? |
|
[x] |
They are broken down by microorganisms |
[ ] |
They get rained on |
[ ] |
They slowly sink into the ground |
[ ] |
Sunlight breaks down their chemicals |
|
|
10.
|
How is the CO2 from the air introduced into a food web? |
|
[ ] |
Plants breathe it in and when an animal eats the plant, it eats the CO2 as well |
[ ] |
It forms carbonate rocks that eventually come to the surface |
[x] |
Plants use the products of photosynthesis to manufacture carbohydrates, fats and proteins |
[ ] |
Bacteria living in nodules on the root convert it into plant food |
|
|