1. STAGES OF DECOMPOSITION
This ppt contains graphic images. The pictures are on slides that do not contain information so feel free to avert your eyes. Information is also graphic and can be disturbing

2. STAGE 1 : THE LIVING PIG
Intestine contains a diversity of bacteria, protozoans and nematodes.
Some of these micro-organisms are ready for a new life, should the pig die and lose its ability to keep them under control.

4. STAGE 2: INITIAL DECAY 0-3 days after death
Although the body shortly after death
appears fresh from the outside, the
bacteria that before death were feeding
on the contents of the intestine begin to
feed the intestine, break through and
begin feeding on surrounding organs
Oxygen deprived cells, make ATP through
anaerobic fermentation lowering cell’s pH. Low levels of ATP halt cell productivity and are unable to synthesis critical molecules and the high acidity in the cell denatures proteins and membrane structures
From the moment of death flies are attracted to bodies. Without the normal
defenses, blowflies and house flies are able to lay eggs around wounds and natural body openings (mouth, nose, eyes, anus, genitalia).

7. STAGE 3: PUTREFACTION 4-10 days after death
Individual cell membranes break down, releasing their contents and enzymes into body creating pressure within the body
The build up of gas resulting from the intense activity of the bacteria This inflates the body and forces fluids
out of cells and into the body cavity.
The young maggots move throughout the body, spreading bacteria, secreting digestive enzymes and tearing tissues with their mouth hooks.

10. STAGE 4: BLACK PUTREFACTION 10-20 days after death
The bloated body eventually collapses, leaving a flattened body whose flesh has a creamy consistency. The exposed parts of the body are black in color and there is a very strong smell of decay
By this stage, several generations of maggots are present on the body and some have become fully grown. They migrate from the body and bury themselves in the soil where they become pupae.

13. STAGE 5: BUTYRIC FERMENTATION 20-50 days after death
All the remaining flesh is removed over this period and the body dries out. It has a cheesy smell, caused by butyric acid, and this smell attracts new organisms.
Beetles feed on the skin and ligaments. Many of these beetles are larvae. They hatch from eggs, laid by adults, which fed on the body in earlier stages of decay.

16. STAGE 6: DRY DECAY 50-365 days after death
The body is now dry and decays very slowly. Eventually all the hair disappears leaving the bones only.
Animals which can feed on hair include tineid moths, and micro-organisms like bacteria. Mites, in turn, feed on these micro-organisms.

19. Mummification
Decay in dry conditions, both warm and cold, with strong air current leading to increased water loss
In deserts, cold places
Murder victim placed in chimneys
Can be preserved for hundreds and thousands of years (provided there are no insects feeding on them).

20. Factors Affecting Speed of Decay
Microbial, insect and vertebrate activity on the dead body can be influenced by:
Geographical location
Time of year
Exposure to sunlight
Combination of sun and humidity will lead to different outcomes
Wrapping and confinement
Burial
Type of soil (clay, pH, mineral composition)
Burial dept
Hanging above ground
Burial underwater
Wounds
Infections
Burning
Chemical treatment

21. Summary of Factors PROMOTING DECAY DELAYING DECAY
Oxygen supply not restricted
Warm temperature (15-37°C)
Humid atmosphere
Presence of invertebrate detritivores (e.g. blowfly larvae)
Wasp, ant and other invertebrate predators feeding on corpse
Wounds permitting invertebrates easier access to internal body tissues
Surface burning causing skin to crackand thereby allowing easier access of invertebrates and oxygen to internal tissues
Obesity
Suffering from septicaemia or myiasis before death
Body exposed to the environment above ground
Body resting on soil
Oxygen supply restricted
Cold temperature (<10°C; decay will cease below 0°C)
Dry atmosphere
Absence of invertebrate detritivores
Wasp, ant and other invertebrate predator sfeeding on detritivores
Inability of detritivores to gain access to all or part of the corpse
Intense burning resulting in tissues becoming carbonized and drying out.
Burial on land or underwater (rate of decay declines with increasing depth)
Body suspended above ground (e.g. hanging)
Formation of adipocere
Mummification
Embalming