Today’s objectives: describe the carbon cycle describe the nitrogen cycle
Starter:
1. State 5 ways that carbon dioxide is released into the atmosphere.
2. State 2 ways in which carbon dioxide is removed from the atmosphere.
3. Why is the excessive production of carbon dioxide a threat to an ecosystem?

• http://www.bbc.co.uk/learningzone/clips/globalwarming-carbon-dioxide-and-acidification-of-theoceans/7050.html
• Carbon Cycle
• Fill in the gaps on the sheet.
• Colour in the producers (sources) of carbon one colour and colour the removers (sinks) of carbon another.

• http://www.bbc.co.uk/learningzone/clips/recy cling-nutrients/4172.html
• Nitrogen cycle
• Fill in the table to complete the nitrogen cycle.

Description of what occurs
Plants absorb nutrients from the soil and use them for growth
Part of nitrogen cycle
Plants and animals die and decay
Animals excrete waste
Animals eat plants

Description of what occurs Part of nitrogen cycle
Plants absorb nutrients from the soil and use them for growth nitrates in soil
 proteins in plants
Plants and animals die and decay proteins in plants and animals
 nitrates in soil
Animals excrete waste
Animals eat plants products from breakdown of proteins
 nitrates in soil protein in plants
 proteins in animals

What is the role of bacteria in the
Nitrogen cycle?
Answer the final activity from the worksheet.

• Activity 3 (High demand)
• Q1 Lightning; nitrogen-fixing bacteria in the roots of beans and peas; nitrogen-fixing bacteria in the soil; decomposition by bacteria and fungi.
• Q2 By the decay of nitrogen-containing plants and animals and their urine and faeces; and by denitrifying bacteria.
• Q3 Fertilisers contain nitrates; plants need nitrates to create proteins, which help them grow; fertilisers are added to help plants grow.

Plenary – key words
Can you define all these words?
• carbon
• carbon cycle
• carbon dioxide
• combustion
• respiration
• decomposition
• nitrogen cycle
• nitrates
• proteins
• photosynthesis

To do:
1. Put some sand in a bottle.
2. Put some gravel on top of the sand.
3. Fill the bottle 2/3 full with
salt water (brine).
4. Put a few drops of plant food in the water.
5. Put some brine shrimp eggs into the bottle.
6. Test the water for nitrates.
7. Leave for a few weeks.

What would you expect to happen to your ecosystem over time?
What would you expect to happen to the nitrate level in your ecosystem over time? Why?