Forensic Science

These flash cards are to help you revise forensic science and what happens to a body when someone dies.

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Time of Death

  • Body temperature drops.
  • Metabolic reactions slow down and stop.
  • Body stops producing heat.
  • Heat is lost into surroundings.
  • Graph plateaus before dropping as not all body reactions stop straight away.
  • There are factors that affect body temperature
  • A body outside will cool more quickly than inside.
  • Body fat acts as an insulator.
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Rigor Mortis

  • Stiffening affect in the body which starts 2-4 hours after death.
  • It begins in the face and neck and slowly progresses down the body.
  • The amount of ATP present in the body affects how quickly it sets in.
  • Different people have different amounts.
  • Depends on the amount of activity an individual participates in.
  • Temperature can affect rigor mortis.
  • It's not permanent.
  • Muscles soften as enzymes break it down.
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Stages of Succession

  • Colonisers move to the dead body
  • Anaerobic bacteria are first to arrive. As enzymes break down cells the bacteria spread.
  • Blowflies lay eggs on the body. Maggots hatch and begin feeding on tissue breaking it down.
  • They burrow deeper into the flesh. Maggots pupate and turn into flies.
  • Beetles lay eggs in the body. Larvae feed on maggots.
  • Parasitic wasps arrive and lay eggs in the fly and beetle larvae.
  • The warmer the body, the quicker the decay as chemical reactions are sped up.
  • If a body is exposed then there will be quicker decay.
  • When a body is discovered, forensics collect eggs, maggots and pupate. if live specimens can be saved, forensics will grow them to adults and then identify the species of fly or beetle.
  • This makes calculating time of death accurate.
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