Transcript Decay

The Body Farm
Where does the biomass from a
corpse end up…….
Key Points
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Where do the biomass of a corpse end up?
What are detritus feeders?
What are decomposers?
What can make decay speed up or slow
down?
• Why are decomposers so important in the
natural world?
• How do humans make deliberate use of
decomposers?
The body farm
• http://video.nationalgeographic.com/video/sc
ience/health-human-body-sci/humanbody/body-farm-sci/
Decay and Decomposition
• When living things die, they start to decay.
• This is done mainly by bacteria which secrete
enzymes to break down the dead matter.
• However, it happens a lot quicker if the dead
matter is broken down into small pieces.
• Detritus feeders, such as earthworms and
woodlice, do the job of breaking larger bits of
matter into smaller pieces.
• The work Detritus feeders makes decay much
quicker.
Detritus Feeders
• Eat dead organisms
• Produce their own waste material
• Examples: maggots, worms, etc.
Flies and Maggots
the maggots have mouth parts for scraping off
flesh
Beetles
‘Clothes Moths’ – Latecomers to the
Meal
These eat hair
and fur
Decomposers
• Break down dead organic matter into its basic
constituents:
• The carbon is released as carbon dioxide,
• Minerals released back into the soil.
Decomposers
• Bacteria
• Fungi
Recycling
Bacteria are
largely
responsible for
the recycling of
carbon,
nitrogen and
sulphur into
forms in which
they can be
taken up by
plants
Best conditions for most microorganisms
(and therefore decay) are…
• Warm – speeds up chemical
reactions
• Moist – easier to dissolve food;
prevents microbes from drying out
• Many need oxygen to respire
Rate of development of the immature
stages of blowflies versus.
temperature
Human Use of Decomposers
• Sewage treatment plants – we use
microorganisms to break down the bodily
waste we produce
• This makes it safe to release it into rivers or
the sea
• Sewage works are designed to provide
bacteria and other microorganisms with what
they need – including a good supply of oxygen
Human Use of Decomposers
• Compost Heaps – Grass cuttings, weeds and
vegetable peelings are allowed to decompose.
This happens because microorganisms break
the plant material down. This compost can
then be used as a fertiliser
Create a newspaper article on the
body farm to include…..
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Where do the biomass and of a corpse end up?
What are detritus feeders?
What are decomposers?
What can make decay speed up or slow down?
Why are decomposers so important in the natural
world?
How do humans make deliberate use of
decomposers?
Plan an investigation into the effect of
temperature on the rate of decay.
– Write a question that can be used as the title of
this investigation
– Identify the independent variable
– Identify at least 3 control variables
– Describe as fully as you can the method that you
might use