Forensics Unit 5 Exam Study Guide

Question 1

Principle of Persistency

Answer 1

Once fingerprints are formed during prenatal development, these patterns then remain unchanged throughout our lives and often last even well beyond death to the latter stages of decay.

Question 2

Bertillon System

Answer 2

Measurements of physical features (e.g.,
distance between the eyes, size of nose, length of fingers, etc.), was highly problematic and later abandoned completely.

Question 3

Cheiloscopy

Answer 3

(1902) R. Fischer presented his related work on the furrows of the human lips for individual identification (unique and persistent)

Question 4

(1977) Automated Fingerprint
Identification System (AFIS)

Answer 4

Used digital scans of fingerprints which was upgraded in 1996 to allow for the computerized searches of the entire AFIS fingerprint database

Question 5

(1999) Integrated Automated Fingerprint Identification System (IAFIS)

Answer 5

Automated digital computer submission, storage, and search of the national FBI fingerprint
database is introduced.

Question 6

(2011)Next Generation Identification
System (NGI)

Answer 6

Introduced to ultimately replace IAFIS

Question 7

Integumentary System

Answer 7

forms the outer “boundary” of our bodies and also includes our hair and nails, which are considered “derivatives” of our epidermis (helps to regulate body temperature and protects internal structures/organs)

Question 8

Subcutaneous layer (hypodermis)

Answer 8

Lowest layer/composed largely of fat and connective tissue that contains larger blood vessels and nerves.

Question 9

Middle Layer (Dermis)

Answer 9

Composed mostly of collagen (protein) fibers, elastic tissue, and reticular fibers (cross‑linked fibers that form a fine supporting mesh‑work). Contains: hair follicles, sebaceous (oil) glands, eccrine (sweat) glands, apocrine (scent) glands, and hair erector muscles are found, and blood vessels (helps with cooling).

Question 10

Outermost layer (Epidermis)

Answer 10

ranges in thickness from very thin (about 0.05 mm) to rather thick(around 1.5 mm thick)

Question 11

Melanin

Answer 11

Pigment responsible for skin coloration.

Question 12

Stratum Basale (Generating Layer/base layer/(Epidermis))

Answer 12

column‑like cells constantly divide and push previously formed cells toward the surface, causing these cells to flatten out and ultimately die in the process.

Question 13

Stratum Corneum (Top layer/(Epidermis))

Answer 13

Part of Epidermis which is directly in contact with the outside world, is composed of about 25 layers of dead cells that stay at the surface for about two weeks before shedding and being replaced from layers below

Question 14

Ridges

Answer 14

Tops of individual patterns on finger pads

Question 15

Furrows

Answer 15

Adjacent low valleys/low points

Question 16

Fingerprints may be affected (distorted/lacking) by deep trauma or disease:

Answer 16

Ex.
-eczema, psoriasis, dermatopathia pigmentosa reticularis (DPR) or a disease called scleroderma
-Anti‑cancer drug, Capecitabine, in some instances leads to the disappearance of a person’s fingerprints

Question 17

Henry System

Answer 17

Fingerprints are sorted by physically matching characteristics for one-to-many searching.

Question 18

Three Basic Patterns

Answer 18

Loop,Arch, & Whorl

Question 19

Arch

Answer 19

-Found in about 5% of all fingerprints
-Has ridges beginning at one side of the fingerprint and running completely to the other side of the fingerprint without a backward turn

Question 20

Loop

Answer 20

-Found in about 60%–70% of fingerprints
-Contains ridge lines that enter on one side of the fingerprint, run toward the middle, and then
curve backward to exit on the same side that they entered the pattern

Question 21

Whorl

Answer 21

found in about 25–35% of fingerprints, con‑
tain ridges that complete at least one 360° “circuit” within the pattern, although not always forming a regular circular pattern.

Question 22

Delta

Answer 22

The point of ridge divergence, where the upward and downward deflected ridges meet the looping ridges.

Question 23

Ridges count

Answer 23

The number of ridges between the delta and the core

Question 24

Minutiae & Paths

Answer 24

starting and stopping, fusing, branching, and other features

Question 25

Bifurcation (Minutiae)

Answer 25

where a single ridge splits into two ridges

Question 26

Ridges Ending (Minutiae)

Answer 26

single friction ridge that simply ends

Question 27

Island/Ridge dot (Minutiae)

Answer 27

A short ridge enclosed by other ridges

Question 28

International Association for Identification, IAI

Answer 28

“examiner’s determination that sufficient quantity and quality of detail exists in the prints being compared" (12-16)

Question 29

ACE-V

Answer 29

a process in the identification of friction ridge impressions that follows the steps of: Analysis, Comparison, Evaluation, and Verification.

Question 30

One-to-Many Matching

Answer 30

compare fingerprint features between an unknown print and millions of records in the IAFIS database

Question 31

Identification

Answer 31

use of fingerprints to identify an unknown person from a set of prints. Limitation: uniquely identify a set of “unknown” fingerprints by matching their features with candidates in a large pool of possibilities one-to-many matching

Question 32

Authentication

Answer 32

comparing a set of fingerprints from a person with either just one reference set or to a very small number of “standard” possibilities, called one‑to‑one matching.

Question 33

Visible Prints

Answer 33

Prints which can be seen with the naked eye without use of any special chemicals or tools. (e.g. fingerprints found in paint, ink, dirt, or blood)

Question 34

Latent Prints

Answer 34

Prints which are not visible to the naked eye ( deposited chemicals from our fingers remain in place when undisturbed for decades, rendering a clear fingerprint pattern left to be found).

Question 35

Dusting (Latent Prints)

Answer 35

Using a dust/fine powder (charcoal. magnetic, fluorescent based) to dust across the surface using a delicate brush. The powder will then stick to the oils and moisture in the prints. When the excess is brushed away only the detailed print remains

Question 36

Ninhydrin (Latent Prints)

Answer 36

Reacts with the amino acids found in the print and, upon gentle heating to speed up the otherwise slow chemical reaction, it forms a purple/blue‑colored pattern of the fingerprint

Question 37

Iodine (Latent Prints)

Answer 37

Elemental iodine (I2) reacts readily with the oils left behind from our fingers to form a somewhat transient, but observable, brown color where the finger oils were deposited.

Question 38

Impression (plastic) Prints

Answer 38

Someone touches a soft, pliable surface, such as clay, putty, wax, or wet paint, they may leave behind an impression of the ridge pattern of their fingerpads or fingers

Question 39

Preservation of Prints

Answer 39

-lifting fingerprints: The tape is carefully placed over the print and then rubbed to ensure that the adhesive on the tape makes full contact with the print. the tape is peeled away from the surface and applied to a card for permanent storage.

Question 40

U.S. Scientific Working Group on Friction Ridge Analysis, Study, and Technology (SWGFAST)

Answer 40

Statement "forensic friction ridge impression examination 'is an applied science based upon the foundation of biological uniqueness, permanence, and empirical validation through observation' and is, therefore, an accepted scientific discipline that meets the requirements set forth in the Federal Rules of Evidence"

Question 41

Flexion Creases

Answer 41

Places where the skin flexes or folds to cause breaks in the observed ridge patterns.

Question 42

Distal transverse crease

Answer 42

Major crease runs in our palms “underneath” our fingers

Question 43

Proximal transverse crease

Answer 43

Runs parallel to this first crease but closer to the arms

Question 44

Radial transverse crease

Answer 44

Three creases break the palm into three separate regions for more detailed analysis.

Question 45

Lip Patterns

Answer 45

-Lips have been shown to contain many “elevations and depressions” -Not unique as ridge patterns can be altered by changing the positioning of the lips.

Question 46

Cheiloscopy (2)

Answer 46

study of lip groove patterns

Question 47

Hair

Answer 47

-An appendage that grows from a follicle in the skin of mammals only. - Helps to regulate the body temperature of an organism

Question 48

Fur

Answer 48

Hair that comes from non‑human mammals

Question 49

Hair Composition

Answer 49

- 80–90% protein( keratin and melanin) - 8% to 15% water -remainder mostly as lipids.

Question 50

Eumelanin

Answer 50

-Dark hair pigment - colors black and brown hair

Question 51

Pheomelanin

Answer 51

-main coloration chemical found in red (ginger) hair

Question 52

Follicle

Answer 52

A tiny hole in the skin located within the outermost layers of the skin and consists of a root, shaft, and tip.

Question 53

Sebum

Answer 53

oily material that protects, lubricates, waterproofs, and helps to inhibit the growth of microorganisms on the hair

Question 54

Cuticle (outermost layer of hair shaft)

Answer 54

which appears similar to the shingles on a roof or the outer scales of a snake’s skin, with the exposed portion of the “scale” aimed toward the tip of the shaft

Question 55

Imbricate (“shingle‑like”) patterns

Answer 55

Found in human hair, appears as flattened scales.

Question 56

Cortex (middle layer (Underlying))

Answer 56

makes up most of the bulk of the hair shaft and gives the hair its characteristic elasticity, stretching up to 30% of its length without breaking

Question 57

Medulla

Answer 57

This part of the hair is characterized by either very spongy cells or no cells at all, forming a canal‑like structure in the center of the shaft, often called the medullary canal

Question 58

Medullary Index

Answer 58

used to help distinguish human hair from that of other animals. In many animals, the MI is greater than 0.5 but in humans it is typically found to be less than 0.3

Question 59

Vellus

Answer 59

Fine short hairs (peach fuzz)

Question 60

Terminal hair

Answer 60

Colored hair which forms on other areas of the body besides the brows and scalp (but can be found on the scalp, armpits, chest hair, and pubic hair)

Question 61

Hair Growth

Answer 61

Hair growth occurs in a cycle composed of three main stages: the anagen, catagen, and telogen phases

Question 62

Anagen

Answer 62

- phase is the part of the cycle in which active growth occurs. -hair shaft is produced

Question 63

Catagen

Answer 63

transitional phase and usually represents about 3–5% of all body hairs at any given time. -Hair growth stops and the portion of the follicle and hair root shrinks.

Question 64

Telogen

Answer 64

resting period for the follicle. In this phase, the detached club root has completely formed. -Hair is detached (club root) and hair can fallout

Question 65

Exogen Phase

Answer 65

-sometimes considered - it is associated with the hair fiber itself rather than with the follicle and simply has to do with the loss of the hair shaft from the follicle