Forensic estimation of time of deathEdexcel International A Level Biology: Flashcards

Exam questions on Forensic estimation of time of death

1. A body is found in woodland at 08:00. A pathologist measures the rectal temperature as 29.5 °C. Normal body temperature is 37.0 °C and the air temperature overnight was 12 °C. For this investigation assume that a body cools at a constant rate of about 1.5 °C per hour.
   Calculate the minimum time since death.2 marks
2. A pathologist examines a body at 14:00. The eyelids and jaw are stiff, but the large leg muscles are still flexible. A second body, examined 40 hours after death, has muscles that were rigid but have become flaccid again.
   Explain why the muscles become rigid after death.2 marks
3. A body is found in a flat in August. The room temperature was constant at 22 °C. An entomologist collects insects from the body. For the blowfly species present, the eggs hatch after 1 day at 22 °C, the larval stage lasts 5 days and the pupal stage lasts 4 days. The oldest insects found were pupae that had been in the pupal stage for 2 days. No beetles were found on the body. Blowflies lay eggs on a body within hours of death.
   Calculate the minimum time since death and explain why your answer is a minimum.3 marks