l7 Taphonomy, Anthropology, Entomology Flashcards
forensic pathologists
Investigative personnel, typically
medical examiners or coroners,
who investigate the cause, manner, and time of death of a victim
in a crime; can also be a physician
who has been trained to conduct
autopsies
autopsy
A surgical procedure performed by
a pathologist on a dead body to
ascertain—from the body, organs,
and bodily fluids—the cause of
death.
cause of death
Identifies the injury or disease that
led to the chain of events resulting
in death
petechiae
Pinpoint hemorrhaging often
observed in the white area of the
victim’s eyes; often observed in
strangulation cases.
manner of death
A determination made by a
forensic pathologist of the cause
of death. Five broad categories
are homicide, suicide, accidental,
natural, and undetermined.
algor mortis
A process that occurs after death in
which the body temperature continually cools until it reaches the
ambient or room temperature.
livor mortis
A medical condition that occurs
after death and results in the settling of blood in areas of the body
closest to the ground.
rigor mortis
A medical condition that occurs after death and results in the stiffening of muscle mass. The rigidity of the body begins within 24 hours of death and disappears within 36 hours of death.
forensic anthropology
The use of anthropological knowledge of humans and skeletal
structure to examine and identify
human skeletal remains.
forensic entomology
The study of insect matter, growth patterns, and succession of arrival at a crime scene to determine the time since death
postmortem interval (PMI)
length of time that has elapsed since a person has died
what are some responsibilities of board-certified forensic entomologist?
promote education, research, and the
practice of medico-legal entomology in forensic science
what is a blowfly’s life cycle?
egg, larvae, pupae, adult
in what environment do female blowflies lay their eggs?
moist environments, they feed on fluid
what are maggot’s role in decomposition?
feed on flesh
what are primary colonizers? examples?
first insects to arrive at a body, blowflies
what is a characteristic of beetles?
eat eggs and larve from flies
how can stages of decomposition be identified?
physical characteristics, insect population, and volatile organic compounds
what factors highly affect decomposition?
temperature and humidity
what are the 5 stages of decomposition?
fresh, bloated, active decay, advanced decay, dry
explain the “fresh” stage of decomposition
immediately after death till body is bloated –chemical breakdown occurs
-few morphological changes
-no odour to humans
explain the “bloated” stage of decomposition
-accumulation of gasses from the activity of anaerobic bacteria produce a swollen, bloated appearance
-obvious odour present at this time.
explain the “active decay” stage of decomposition
-deflation of the carcass due to the gases escaping from body often due to the insect activity
-strong putrid odour
-when the strongest odours are detected
explain the “advanced decay” stage of decomposition
-large amount of the flesh has been removed
-but still some moist tissue present
-odour noticeable but less putrid than active decay
explain the “dry” stage of decomposition
-carcass reduced to bones, cartilage, some
exudate, and dry skin
-slight odour is present.
-insects at this stage using skeleton as shelter
what is post mortem interval (PMI) in entomology?
entire period after death, pre and post coloniation
what is Minimum post mortem interval
(minPMI)? why is it called minimum pmi?
shorted possible time from death to when first flies lay eggs and, therefore colonize the body
-“minimal” as there could be a delay –pre-colonization period
how is pre-colonization period useful?
important to know to determine possible delays in the arrival of insects on a body
what is time of colonization(TOC)? what does it include?
indicates time of colonization, includes myiasis
what is myiasis?
parasitic infestation on a live host
explain the method of insect development to determine minPMI
-Require oldest immature insects on or around the body
-goal is to determine when the female flies first laid eggs on the body (primary colonisers)
-Temperature is essential
-method is no longer valid once the first colonisers have reached the adult stage
what is essential info to know when trying to age insects?
species
why is temperature important in entomology?
insects are cold-blooded and will develop faster at warmer temps
explain the successional ecology method for determining minPMI
-Body goes through rapid biological, chemical, and physical changes
-Attractive to a predictable sequence of insects
-Require the assemblage of all insects, not just one species
-Varies with habitat, season, geographic area
what are 6 applications of forensic entomology?
-Post mortem interval
-Neglect
-Entomotoxicology
-Extracting human DNA
-Disposal of body
-Movement of the body after death
explain how entomology can be used to identify neglect?
certain species attracted to live hosts
-vunerable persons, unsanitary conditions
-greenbottle flys feed on decomposing tissue
-houseflies attracted to feces
explain Entomotoxicology?
insects can ingest drugs found in human system, insect tissue can be tested for presence of drugs
explain how entomology can be used to extract human DNA?
extract stomach from larvae in attempt to recover DNA
how can entomology be useful to gain info about the disposal of a body?
location affects decomp and insect colonization
(ex if body is in a cold freezer it changes how insects colonize)
how can entomology be useful to gain info about the movement of a body?
native insects can determine if a body was moved, if the body has insects different than those native to the location it is found, we know the body has been moved
explain two instances where insects can cause damage to evidence on a body
-Larvae may move clothing to appear like a sexual assault took place
-Feed on tissue around a wound, destroying evidence
what is the primary focus of a forensic entomologist? what is the most important piece of info to a FE?
-determine minPMI
-temperature
postmortem redistribution
redistribution of drugs in the blood after death
autolysis
self-digestion by the cell’s own enzymes
adipocere
formation of a waxy substance during decomposition
putrefaction
decomposition carried out by microorganisms
slippage
skin begins to blister and peel
vitreous humor
fluid within the eye
forensic anthropologists may help to create a ______ to help with victim ID
facial reconstruction
t/f Bones are static, dead structures within the body
false, dynamic living tissue that undergo constant change
what part of a decedent’s body resists rapid decomposition and is used by forensic anthropologists to provide info of the deceased
bone
t/f decomposition typically occurs on the face before the abdomen
false, usually begins in the abdomen
three things that must be taken into account when using entomological evidence to estimate PMI
-geographical location of body
-weather conditions
-location’s climate over time
the stage of fusion of various bones within a skeleton can be used to estimate the ____ of the decedent
age
t/f forensic entomology can provide valuable insight into the manner of death of an individual
true
as a forensic entomologist, why is it important to keep some insect specimens alive after collection
enables accurate measurement of larvae
insect evidence should be collected..?
at the scene by a forensic entomologist or trained investigator
Putrefaction and autolysis are two types of ____ processes
rigor mortis
Forensic taphonomy
study of what happens to the body and how the environment impacts on these processes between the death and discovery of human remains
what are taphonomic factors and why are they important?
factors that affect decomposition and preservation of a body, factors interact with others and as a result the effects on decomposition can vary enormously
examples of taphonomic factors?
depth of burial- deeper bodies more protected
wrapped bodies- more protected
soil type- acidic soil can break down bones
plant and animal activity- lots of factors affect the amount of this
temp- MOST IMPORTANT, higher temps mean more bacteria and biological activity so faster decomp
briefly explain the parts of a bone
compact bone- outer layer, smooth white appearance
spongy bone- under compact bone, allows room for blood vessels and marrow
medullary cavity- innermost layer, stores bone marrow
epiphyses- ends surrounding long bones
what are the 5 classes of bones, provide an example for each
long bones- arms and legs
short bones- fingers, toes
flat bones- skull, pelvis, ribcage
irregular bones- spine, mouth
sesamoid bones- joints (knees, hands, wrist, feet)
how many bones do humans have as newborns? as adults?
405–>206
Ossification centers
areas in the body where bone formation begins, bones fuse together as we grow
what are 6 pieces of information we can gather from bones?
sex, age, ancestry, stature, trauma, disease
explain key differences between pelvis bones that can help determine sex
females will have:
-wider subpubic angle
-wider sciatic notch
-broad pelvic inlet
explain key differences between cranium bones that can help determine sex
males will have:
-more pronounced features
-more square chin
-wide and robust jaw
-sloped forehead
explain how bones can be used to estimate age
-teeth
-bone density (less dense as we age)
-fusion of bone (different fusion stages based on age)
-bone disease and trauma (would be documented in medical records)
explain how bones can be used to estimate stature?
long bone length is roughly proportional to height, measurement is a range
how can bones be individualized?
combining a range of traits such as age, stature, sex, and trauma can help to narrow down the possibilities to attempt to ID deceased persons
what are the three types of bone trauma? explain each
antemortem trauma- healed trauma prior to death
perimortem trauma- occurred at/ around time of death
postmortem trauma- after death
how can skeletal remains be dated?
lab tests
what are some responsibilities of forensic anthropologists?
-consultants
-expert in Office of the Chief Coroner
-academics
-testify in court
-participate on international forensic teams (mass fatalities, war crimes)
