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126 Cards in this Set
- Front
- Back
What is forensic science?
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The application of science to law
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What is the CSI effect?
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Dramatization of crime shows which lead to people expecting unrealistic expectations
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What is the Locard Exchange Principle?
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When two objects come into contact with each other , there is exchange of materials between them
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What is the Frye Standard?
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court must decide whether the questioned procedure, technique, or principle is "generally accepted" by a meaningful segment of the relevant scientific community. This creates a problem for new sciences
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What is the Daubert Standard?
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Trial judges assume responsibility for acting as gatekeeper in judging the admissibility and reliability of scientific evidence presented in their courts.
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What is an expert witness?
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An individual who possesses knowledge of specifics that is relevant to a case that is not expected to from an average layperson
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Name the 3 NAS recommendations that apply to Canada
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$$ - make all public forensic laboratories independent of law enforcement and prosecutors offices - RCMP loses their lab
All FS labs must be accredited and all FS must be certified professionally - Not everyone is accredited and to be accredited = PhD Eliminate all Coroner's system, replacing with Medical Examiner systems |
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What is individual characteristics?
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Evidence that can be attributed to a common source with extremely high degree of certainty.
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What is class characteristics?
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Evidence that can be associated only with a group and never a single source. For comparing multiple characteristics, you can use the product rule.
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What is the difference between individual and class characteristics?
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Individual is linked to usually, one thing/person while class is associated with a group.
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What are the various databases Forensic Scientist have?
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Fingerprint, DNA, shoe print, ballistics, and paint data
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What is a pathologist and forensic pathologist?
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pathologist are scientist that research cancer itself while forensic pathologist are the ones who perform autopsies to find the cause of death
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What is rigor mortis?
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when the body stiffens after death
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What is algor mortis?
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when the body's temperature increases or decreases when you die depending on the ambient temperature
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What is livor mortis?
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when blood sinks to the lowest point of the body at death due to the pumping of blood seizing
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What happens to the eye after death?
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You have the effect of trucking(where blood is broken up in the eye) as well as potassium levels increase in the eye
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What is the difference between a male and female pelvis?
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a female pelvis is more circular to allow for childbirth while males are more heartshape
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What is the difference between a male and female skull?
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The male skull is larger, has a more sloped cranium and more distinct protruding features such as brow line as well as higher cheek line
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What body part do we use to determine sex?
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Pelvis or skull (males have more protruding brows and higher cheek line)
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What body part do we use to determine age?
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skull(fusion), teeth, fusion of epiphyseal regions, as well as other reference standards
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What body part do we use to determine race?
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The skull
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What features of the skull can we use to determine race?
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the eye sockets are various shapes(mongoloids are rounder, Caucasoid are oval and Negroids are square), as well as nasal cavity (mongoloids are small and round, Caucasoids are long and narrow, and Negroids are wide)
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What is so special about bite marks?
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Every person has a different bite mark like a fingerprint
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When do baby teeth develop?
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starts at 4 months in utero with tooth eruption starting around 6 months
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When do adult teeth develop?
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soon after birth with eruption usually takes 6-8 years with 2 years extra for roots to develop
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How many teeth do humans have?
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20 primary teeth and 32 permanent teeth
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What are the 2 bones in the jaw called?
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Maxilla (upper jaw), and mandible (lower jaw)
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How are teeth numbered?
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upper right to upper left tooth = 1-16 and lower left to lower right is 17-32. Basically create a C in front of your face.
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What are 4 statements that forensic dentist can provide about teeth?
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Teeth are consistent via X-ray or photograph, differences can be explained from fillings, teeth aren't consistent, or undetermined
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What are some issues with forensic dentistry when identifying teeth?
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Dismemberment, incomplete dentition, complete tooth loss, and changes due to fire. However the major issue is an incomplete dental record.
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Why is it easier to get bite mark patterns on a dead person compared to a living?
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a living persons bite mark can begin healing within 8 hours while a dead persons does not
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Why do we swab bite marks twice?
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One time to collect saliva and the second time to collect DNA
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What is the role of forensic anthropologist?
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to determine if it is human or animal as well as to determine age, sex, stature, ancestry, anomalies, pathology, individual features. As well as the age of remains and trauma events perimortem(near death)
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What is the role of forensic taphonomy?
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Interpretation of mainly outdoor death/post-mortem processes such as mummification, decomposition, saponification, and modification by external objects (water, etc)
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what is the role of forensic archaeology?
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Recovery of scattered or burial remains
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What are we considering when we find buried remains?
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are they human and is this an unmarked historical grave that was dug up
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What is race?
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It is the physical appearance of a person, such as mongoloid, negroid, or Caucasoid. It is not ethnicity
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What does ossification mean?
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When cartilage turn to bone on the shaft (Diaphysis) and tips (Epiphysis)
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How many bones does a human body have?
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206
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What is the term shoveling for teeth mean?
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Mainly Asian or Native American ancestry, anterior thicker around margins on lingual (tongue) side
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How does bone density change with age?
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Peak in 20s, high in 30s, decline in 40s
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What is osteoarthiritis?
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Deterioration of joint, use-wear and inflammation, occuring usually after age 40
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How does the pubic bones morph with age?
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Pubic symphysis: right and left pelvic halves join in front of body with band of cartilage, as well as surface changes where it smooths out
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How does the sternum change with age?
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You can determine it base on the fourth rib at end of sternum
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How do we measure stature?
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hard because people tend to exxagerate height on drivers license as well as you are taller when you decompose because muscles that hold you together is gone. Lastly, the main method to measure the long bones (femur or humorous)
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What is a tentative identification?
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it is a possibility but cannot be sure and is a narrowing to one person
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What is a positive identification?
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it is that person and that person only
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What is the difference between tentative and positive identification?
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one is a possibility (such as finding a wallet) while the other is, it has to be them (surgical pins)
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What are examples tentative identifications?
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wallet, shoes patterns, jewelry, car registration.
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What are examples positive identification?
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dental, DNA, fingerprint, visual, surgical pins
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What are examples of both tentative and positive identification?
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tattoos, piercings, scars
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What are some perimortem injuries (injuries found near death)?
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broken bones with no signs of healing, bony scars, blunt/sharp trauma injuries
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What are some antemortem injuries (injuries found before death)?
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bone fractures healing slightly
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How to identify a cat/dog has scavenged a remain?
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V-shape bite marks are usually canines, scratch marks are from cats/dogs, and head to toe eating patterns
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How to tell if a rodent as scavenged a remain?
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tightly circumscribed, and parallel incisor grooves
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What is root etching?
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When roots engrave itself into buried remains and create damage by either movement or humic acid
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What is issues in taphonomy?
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Lack of standard nomenclature, Unsynthesized and scattered data sets, lack of data sets, and researchers who lack knowledge based on coming from multifaceted fields
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What is trucking?
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When columns of blood are broken up in the eye after death
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What are some early changes to the body after death?
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trucking, eye becomes soft, body becomes flaccid, semen and vomit may emerge
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What happens to the body during rigor mortis?
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the body stiffens due to glycogen levels changing to myosinogen, a gel like substance due to the pH level of the body lowering from lactic acid build up.
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How long does rigor mortis last?
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usually comes on after death in the small muscles (eyes, mouth), and last up to 24 hours or so
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What is the time period for rigor mortis?
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if body is warm and flaccid - less than 3 hours
if body is warm but stiff - 3-8 hours if body is cold and stiff - 8-36 hours if body is cold and flaccid - 36 hours or more |
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What is Cadaveric Rigidity?
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When certain parts of the body becomes rigid after death due to stressful conditions. ie, the hand holding a gun becomes stiff during a gun suicide
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What is the rate of cooling for core body temperature after death?
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1/2 to 3/4'C from 37'C
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What happens to livor mortis when the body is in contact with a surface?
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the blood vessel constricts so there are pale marks where the body is against a hard surface
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When does livor mortis become visible?
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Usually 2-3 hours after death
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What are variables affecting algor mortis?
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mass of body, mass/surface area of body, posture of body during death, clothing, obesity, emaciation, oedema, environmental temperature, wind, rain, humidity, hypothermia, hyperthermia
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What are 2 ways to measure core body temperature?
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using a thermometer and inserting 10cm into the rectum or making an incision into the core of the body
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What are the means of measuring time of death for a person?
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rigor mortis, algor mortis, livor mortis, digestion, insect growth, and potassium level in the eye
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What are the 4 body decompositions?
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mummification, saponification, putrefaction, and skeletonization
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What is putrefaction?
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Where the body decomposes due to bacteria in the gut eating the body and releasing a gas causing bloating. It is temperature dependent and the most resistant organs are the prostate and uterus
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What is saponifcation?
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where the body's fat turns into a chalky substance like a soap, preserves the body well where it occurs in 3 weeks and can last for years
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What is mummification?
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where the body dries due to a dry area or due to wind. It preserves the body very well.
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What is skeletonization?
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where the body turns to bones, can take 1-2 years to fully skeletonize and can last for 40-50 years depending on conditions.
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What is forensic entomology?
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to determine the time of death of a person using insect colonization
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Why is it important to give people a time of death?
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to give closure, homicide, legal implications, and fraud cases
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What are the 2 ways in forensic entomology to determine time of death?
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larval diptera and successional colonization of insects
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What are the stages of larval diptera?
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first instar where the larvae cannot intrude into human skin itself and needs to be placed in an open wound.
second instar, where the larvae now larger and can protrude into human skin by wiggling third instar, where the larvae is large and can tear through tissue quickly wandering/nonfeeding stage, where the third instar goes into a hiding spot to change into a blow fly |
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What does the new blow fly look like once it emerges out of its pupae?
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It has thin and weak legs, it has crumpled wings, and is grey and dull looking, not like the black colourful ones we see
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How long before a blow fly can fly?
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24 hours
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What are variables to consider when looking for insects on a dead body?
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the oldest stage of the insect found, the species, the temperature, and the development data for that insect
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How can we determine if a body has been moved after death via entomology?
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if the body has been moved geographically where an insect is not geographically found
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How can we determine body disturbance via entomology?
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if a body is buried but there is huge amounts of insect infestation which means it was above ground when died
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How can we determine wounds with entomology?
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It can give indication of where wounds are, even tiny pricks of needles and can show defense wounds
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How can we link suspects with entomology?
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Locard Exchange Principle, some suspects can take larvae with them
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How can we find drug substance of a dead body using entomology?
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the insects feed on tissue and the tissue may contain drugs. Secondary insects that eat the primary insect may also contain these drugs in them
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How can we show abuse with entomology?
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Can show if abuse is happening when people who have open wounds on them in health care facilities have larvae development. The insects can actually clean the wound of the abused person because it only eats dead tissue.
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How do you collect blow fly evidence?
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If it is first instar to third instar, collect half and put in alcohol to preserve it, and the other half in a container with holes with beef liver + wet paper towel to harvest.
Collect the oldest if possible Pupae does not need food and collect empty pupae shells Temperature should be taken at various points away from the sun Soil should be taken around the crime scene |
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What are some challenges to forensic entomology?
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temperature, the temperature is never exact since we don't know the exact temperature of location, just an estimate
seasons can change conditions exclusion of insects can occur if body was frozen or wearing a lot of clothing |
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What is important about the Wayne Williams case?
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they used fiber evidence as well as probability to find out he was the killer. That they can use class evidence and the probability to make it into an individual evidence
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What is the difference between a medical examiner and coroner?
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Coroner is a lay person and has judicial powers
Medical examiner is a doctor and has no judicial power |
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What are examples of class evidence?
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blood type, fiber, bullets(caliber)
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What are examples of individual/accidental evidence?
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DNA, fingerprints, bullet(etch marks)
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What is the relationship between probability and significance?
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they are inversely related, where one goes up, the other goes down
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What is the product rule?
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multiplying probabilities to give a lower probability
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What is normative standard?
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reference set of data based on a normal population, it is not an average
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Why do officers wear body suits in crime scenes?
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Locard Exchange Principle, to protect the crime scene but most importantly, to protect the officer
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Why do officers wear 2 gloves in crime scenes?
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the top layer gets submitted with the evidence to avoid cross contamination
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What is the importance of the Steven Truscott Case?
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Pathologist used digestion as a way to signify time of death but digestion shuts down when a person is in fight or flight mode which made it seem like the Girl died when she was with Truscott
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What are identification officers?
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are actual police officers trained to collect evidence
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What is the case receipt unit?
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a unit that is specialize in knowing exactly where evidence is
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What are some conflicts between forensic labs and identification officers?
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ident wants everything analyzed but there are backlogs and will do 12 items for civilian cases only
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What is trace evidence?
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physical evidence, such as hair, fibre, body fluids, fingerprints, etc etc
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What is Bertillionage?
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a system of identification using 14 physical characteristics each with 5 rankings. This is based on characteristics are inherited independently, but this is false, some are genetically inherited so 2 people sharing the same characteristics is quite high. (An example is dark hair people usually has dark eyes)
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How do fingerprints form?
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in utero and never changes
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What is the problem of normative standards?
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Needs more population to study and a Japanese person in japan may have different standards then a Japanese person who has lived many generations in Canada
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How many points of normative standard is there for the face?
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There are 28 points of various thickness
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What are some visual identification problems?
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least scientific, and can create mistakes due to denial as well as trauma
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What are some problems with fingerprints?
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fingerprints may decompose before collected as well as must have premortem records (so get it from the persons home where they might touch personal items)
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What is DNA?
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DeoxyriboNucleic Acid
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What are the different types of DNA?
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Nuclear(white blood cells, tissue, hair follicle), where we get from both parents so we can get a premortem sample from both parents
Mitochondrial(all of the above + hair shaft), where it comes from mother only and carries on from mother to mother |
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What is video superimposition?
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where they take a skull and can use its features to match it to a photograph, but problems is that it must be of the same angle
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What are the 4 ways of finding time of death?
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Anamnestic (peoples memory of peoples regular patterns), Eye Witness (was present at death but not reliable), corporal (decomposition), environmental (insects + plants)
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What is the "manner of death"?
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how the person died, must use scientific terms so it isn't a murder, its a homicide
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What is the "cause of death"?
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The scientific terms about how a person died, so they didn't die from a stab, they died from bleeding to death
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What is "mode of death?"
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It is the instrument used
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What are the five questions in a death investigation?
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who died? where did they die? when did they die? why did they die?(cause) and how did they die?(manner of death)
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What was the Kumbo Tire vs Carmichael case so significant?
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The Judge is still the gatekeeper but is now of both scientific and TECHNICAL knowledge
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What is the Federal Rules of Evidence Rule 702?
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Reliability of the witness
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What is the difference between Offensive and Defensive bite marks?
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Offensive are usually well define while defensive are not
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How does a bite mark between a living and a dead person differ?
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If bitten before death or living, there is a well defined bruise, if bit after death, no bruising.
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Who opened the first Forensic Science Lab and in what year?
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FBI in 1932
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What are specific criteria's when an expert witness is taking a stand in court?
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They must present facts, and give opinions such as "skid marks indicate speed of car."
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What are techniques used to find buried remains?
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witness statement, visual clues, probing, trenching, area photography, cadaver dogs, remote sensing
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What factors will affect rigor mortis?
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temperature, if the person is young/old (less muscle), and if the person exerted any force beforehand
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What are specific criteria's when an eye witness takes the stand in court?
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They cannot give opinion, like they cannot say "I saw that car was driving too fast."
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