Ocr A2 Biology - Recycling In Ecosystems (Part 1)

Front 1

What does the carbon cycle show?

Back 1

How carbon moves through living organisms and the non-living environment.

Front 2

State three processes that involve organisms and two chemical and/or physical processes involved in the carbon cycle.

Back 2

• Involves organisms
  Photosynthesis
  Respiration
  Decomposition
• Chemical and/or physical
  Combustion
  Weathering

Front 3

All organisms need carbon to make essential compounds. Give an example of a reaction that requires carbon to make an essential compound.

Back 3

• Photosynthesis
• Uses CO2 to make glucose

Front 4

What is stage 1 of the carbon cycle?

Back 4

• Carbon (in the form CO2 from air and water) is absorbed by plants when they carry out photosynthesis.
• It becomes carbon compounds in plant tissues.

Front 5

What is stage 2 of the carbon cycle?

Back 5

• Carbon is passed on to primary consumers when they eat the plants.
• Carbon is then passed onto secondary and tertiary consumers when they eat the primary consumer.

Front 6

What is stage 3 of the carbon cycle?

Back 6

• All living organisms die and the carbon compounds in the dead organisms are digested by microorganisms called decomposers e.g. bacteria and fungi.
• This process is called saprobiontic nutrition.

Front 7

What is stage 4 of the carbon cycle?

Back 7

• Carbon is returned to the air and water as all living organisms (including decomposers) carry out respiration, which produces CO2.

Front 8

What happens if the dead organic matter ends up in places where there are not any decomposers e.g. deep oceans or bogs?

Back 8

Their carbon compounds can turn into fossil fuels over millions of years (by heat and pressure).

Front 9

What happens to the carbon in fossil fuels when they're burnt? What is the name of this process?

Back 9

The carbon is released when they are burnt - this is called combustion.

Front 10

As well as coal, other types of rock can be formed from dead organic matter deposited on the sea floor. Give an example of other rocks that can be formed from dead organic matter.

Back 10

• Limestone and chalk
• They are mainly composed of calcium carbonate (CaCO3).
• This comes from marine organisms like crabs, mussels, sea urchins and coral that utilise this compound in their development e.g. forming shells.

Front 11

How can carbon deposited on the sea floor be returned to the atmosphere?

Back 11

• They can be drawn deep into the earth by the movement of tectonic plates.
• They undergo chemical changes and release carbon dioxide, which is returned to the atmosphere by volcanos.

Front 12

The rocks on the sea floor can eventually become land, which is then weathered. State and explain the two types of weathering, and what weathering can result in.

Back 12

• Chemical weathering can occur, where rainwater (which is slightly acidic due to the CO2 dissolved in it) can the rock to erode.
• Physical weathering can occur, where plant roots can cause the rock to split or animals to cause damage to the rock.
• Chemical weathering cane cause mineral and bicarbonate ions (HCO3-) to b released from the rock back into the groundwater. From here, it travels to the rivers and oceans. There they combine to form carbon-containing compounds such as CaCO3.

Front 13

CO2 can .......... directly into oceans from the atmosphere and be transported in the ocean by ....... .......... .......... (a physical process). CO2 can remain in these slow-moving currents for ......... of years before returning to the ........ and being released back into the ......... .

Back 13

1. dissolve

2. deep underwater currents

3. hundreds

4. surface

5. atmosphere