Where does the biomass from a corpse end up……. The Body Farm Where does the biomass from a corpse end up…….

Key Points 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/science/health-human-body-sci/human-body/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 Note the maggot’s mouthparts for scraping bits off dead flesh.

Beetles There are a huge variety of beetles, some of which are detritus feeders. Some, such as the green one on the bottom right, are predators which arrive at a corpse in search of detritus feeders, such as this maggot, which it predates on.

‘Clothes Moths’ – Latecomers to the Meal These eat hair and fur These eat hair and fur. For more on forensic entomology, see: http://www.nhm.ac.uk/nature-online/science-of-natural-history/forensic-sleuth/forensic-entomology/ or http://www.forensic-entomology.com/

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 Break down dead organic matter into its basic constituents: the carbon is released as carbon dioxide, and minerals released back into the soil.

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 Rate of development of the immature stages of blowflies versus. temperature The warmer it is, the sooner the flies emerge…

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….. 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