Recycling in nature and by people
The carbon in your body was once in the air, then in a plant, and one day it will go back. Nature recycles everything it makes. People find recycling what they make much harder.
By the end of this page you can
- Explain why recycling manufactured materials matters, and why it is hard
- Follow carbon round the carbon cycle, including decomposers
- Put the steps of the nitrogen cycle in order
- Tell biodegradable from non-biodegradable, and the nitrogen bacteria apart
- Answer exam questions on cycles and recycling
Goals tick themselves off as you try the activities below.
Photo: John Robert McPherson, CC BY-SA 4.0, via Wikimedia Commons. Cropped.
Bracket fungi breaking down a fallen log. Fungi and bacteria are decomposers: they return the carbon and nitrogen in dead things to the air and the soil.
How often it shows up in past papers
Paper 1 counts come from our past-paper bank of CSEC Biology Paper 1s. Paper 2 is not included yet.
Why recycle, and why it is hard
What people make, such as cans, glass and plastic, does not return to nature the way a log does. Tap each card.
Carbon goes round and round
Carbon moves between the air and living things in the carbon cycle. Tap each step to follow it.
Where does the carbon go?
Tap a step on the list to follow the carbon round the cycle.
Cut down a forest and less carbon dioxide is taken in by photosynthesis, so the level in the air rises.
How nitrogen gets back into plants
Plants need nitrogen to make protein, but most take it in only as nitrates. Start from a dead leaf. Drag or tap each card into its slot.
Where does the cycle start?
Seven terms to know cold
Say what each term means before you flip the card. Most students mix up the three kinds of bacteria at first, so take them slowly.
Six quick questions, then a real one
Pick an answer to see why it’s right or wrong.
Which material is non-biodegradable?
What is the MAIN advantage of recycling?
If all the trees in a large forest were killed by disease, what would most likely happen to the air?
Which bacteria return nitrogen gas to the air?
Peas and beans can make soil more fertile because they
Which of these take part in cycling nutrients in nature? I bacteria, II plants, III earthworms, IV humans
exam style · 2 marks
Explain the role of decomposers in the carbon cycle.
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Practice questions are written by My V.I.P. Academy. They are not official CXC papers.