Transcript B1.21_Recycling_in_Nature2.82 MB

Recycling in Nature
WAL:
What is decomposition and why is it important?
Some
Most
All
• Can you evaluate the conditions
needed for decay to occur?
• Can you explain what role microbes play in the
process of decay?
• Can you describe what is meant by the term ‘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 minutes
To finish: Evaluate which of the following
two designs for compost bins is best.
Justify your choice.
6 minutes
The Body Farm
• Why do you think the study of decomposition
is important?
• Could you do this job? Why/why not?