notes

• extent of decomposition

  • carried out by decomposers eg bacteria and fungi
  • first few days= breaks down cells and tissues- skin is greenish
  • then breaks down tissues and organs= bloating due to gas
  • skin blisters and falls off body- only skeleton remains
  • after years skeleton disintegrates
  • rate determined by temperature and oxygen available
• stage of succession

  • as body decays, species colonising body changes
  • analysing community of species can determine TOD
  • succession stages depend on accessibility to insects and availability of oxygen
• forensic entomology

  • study of specific insects found on dead body
  • different insect species colonise body at different times
  • stage of life cycle insect is at- age of insect can help determine TOD
• body temp

  • respiration and metabolic processes produce heat(exothermic)
  • death= metabolic reactions end and body temp drops
  • HOWEVER- only determine TOD after 24 hours, until body temp reaches its surroundings
  • conditions affect rate heat is lost: air temp, SA:V, presence of clothing
• degree of muscle contraction

  • death= mucles stiffen as ATP is used up
  • calcium ions build up in muscle cells and become fixed in state of contraction(rigor mortis)
  • extent of rigor mortis= determine TOD
  • only up to 36 hours-limited use