Recycling in NatureWhat is decomposition and why is it important?WAL:

All

Most

Some

• Can you describe what is meant by the term ‘decay’?

• Can you explain what role microbes play in the process of decay?

• Can you evaluate the conditions needed for decay to occur?

STARTER QUESTION – What would our world be like if when living

things died they did not decay?

STARTER QUESTION – What would our world be like if when living

things died they did not decay?

What would our world be like if when living things died and they did not decay?

Fruit and Vegetables

http://www.youtube.com/watch?v=c0En-_BVbGc

Meat

http://www.youtube.com/watch?v=C6sFP_7Vezg

Decay

The responsible parties

The breakdown here happens because the materials get digested by maggots and worms etc

The Big Questions:

Why is decomposition important?

What conditions would increase the speed of decomposition?

You have seven seconds to scan the following passage:

A number of organisms play a role in the process of decay. They break down dead plants and animals, and animal waste. There are two main groups of decay organisms:

(1) Detritivores, such as earthworms, maggots, millipedes and woodlice, eat small parts of the dead material, which they digest and then release some as waste. This activity increases the surface area of the dead remains for decomposers to act on.

(2) Decomposers such as bacteria and fungi chemically break down dead material, releasing ammonia into the soil.

Some Questions…

• What key points did you pick up when you skimmed the passage?

• Would it be appropriate to skim read in an exam? Why/why not?

• Now read the passage again accurately. Questions to follow:

A number of organisms play a role in the process of decay. They break down dead plants and animals, and animal waste. There are two main groups of decay organisms:

(1) Detritivores, such as earthworms, maggots, millipedes and woodlice, eat small parts of the dead material, which they digest and then release some as waste. This activity increases the surface area of the dead remains for decomposers to act on.

(2) Decomposers such as bacteria and fungi chemically break down dead material through extracellular digestion, they then absorb the products and release some nutrients such as ammonia into the ground.

Working in pairs, answer the following questions…

1. Name two types of organisms that cause decay.

2. Give a named example of each type of organism.

3. Describe the differences between a decomposer and a detritivore.

6 minutes6 minutes

To finish: Evaluate which of the following two designs for compost bins is best. Justify your choice.

6 minutes6 minutes

The Body Farm

• Why do you think the study of decomposition is important?

• Could you do this job? Why/why not?