September 9, 2014

 Does everyone have a unique fingerprint?  How, why, and when do fingerprints develop? Watch this!

 Does everyone have a unique fingerprint? Yes – even identical twins have different fingerprints.  How, why, and when do fingerprints develop?  Fingerprints are unique b/c they are influenced by minute details of the womb environment (e.g. flow of amniotic fluid around hand)  Fingerprints help us hold things  Fingerprints develop by 24 weeks gestation

 Can you alter your fingerprints? Watch this!

 Can you alter your fingerprints? No, you can form scar tissue over parts of your fingers, but usually enough marks remain for identification.

 Can you alter your fingerprints? John Dillinger (aka Public Enemy Number One) underwent plastic surgery and used acid to try to remove his fingerprints. After he was killed, however, he was fingerprinted in the morgue, and the ‘altered’ fingerprints still matched the originals.

Fingerprints have served as unique signatures since prehistoric times  Early potters & scribes left fingerprints in clay  Businessmen in China’s T’ang dynasty (8 th century AD) used fingerprints on business contracts

Scientific study of fingerprints  1891 Francis Galton  classified fingerprints using loops, whirls, and arches  demonstrated that fingerprints are unique and unchanging

 1892 First reported use of fingerprints to solve a crime, in Argentina.  1899 Sir Edward Henry developed a way of classifying fingerprints so that investigators could quickly narrow down possible matches. “Henry system” of classification Used until computer systems developed  1910 Thomas Jennings is first person in US convicted based on fingerprint evidence

 Automated Fingerprint Identification System  Used since 1960s  Scans, encodes, and searches fingerprint images  After match(es) found, a fingerprint expert evaluates the matches  Problem with current system: not all databases linked

 What ARE fingerprints?  The fingers, toes, palms of hands, and soles of feet have friction ridge skin made of ridges (raised areas) and furrows (valleys). Are ridges dark or light? Why?

 What are the 3 basic patterns?

 Arches enter from one side of the finger, rise in the middle, and exit the other side  Least common pattern (~5%)  Can be plain (low rise) or tented (high rise) Plain arch Tented arch

 Loops enter from one side, rise, and go back out the same side  Most common pattern (~65%)  Have a core (the center of the pattern) and a delta (a triangular area) green arrow = core red arrow = delta

 Loops enter from one side, rise, and go back out the same side  Most common pattern (~65%)  Have a core (the center of the pattern) and a delta (a triangular area) green arrow = core red arrow = delta NOTICE! Only 1 or more of the ridges must enter and exit from the same side to be a loop!

 Radial loops open towards the radius of the arm (i.e. towards the thumb).  Ulnar loops open towards the ulna of the arm (i.e. towards the pinky) Is this a radial loop or an ulnar loop?

 Radial loops open towards the radius of the arm (i.e. towards the thumb).  Ulnar loops open towards the ulna of the arm (i.e. towards the pinky) Is this a radial loop or an ulnar loop? You can’t tell without knowing which hand it came from!

 Radial loops open towards the radius of the arm (i.e. towards the thumb).  Ulnar loops open towards the ulna of the arm (i.e. towards the pinky) If it came from the right hand …

 Radial loops open towards the radius of the arm (i.e. towards the thumb).  Ulnar loops open towards the ulna of the arm (i.e. towards the pinky) If it came from the right hand … Radial!

 Whorls look like “whirlpools”  Have a core and two or more deltas

 Plain whorls are spirals or concentric circles

 Central pocket loop whorls look like a loop with a whirl in the middle

 Plain whorls are spirals or concentric circles  Central pocket loop whorls look like a loop with a whirl in the middle  Double loop whirls have two loops that collide to make an “S” shape

 Plain whorls are spirals or concentric circles  Central pocket loop whorls look like a loop with a whirl in the middle  Double loop whirls have two loops that collide to make an “S” shape  Accidental whorls are irregular

Fingerprint taken from right hand. Hold up your fingers to show the answer: 1. Plain arch 2. Tented arch 3. Radial loop 4. Ulnar loop 5. Central pocket loop

Fingerprint taken from right hand. Hold up your fingers to show the answer: 1. Plain arch 2. Tented arch 3. Radial loop 4. Ulnar loop 5. Central pocket loop

Fingerprint taken from right hand. Hold up your fingers to show the answer: 1. Plain arch 2. Tented arch 3. Radial loop 4. Ulnar loop 5. Central pocket loop

Fingerprint taken from right hand. Hold up your fingers to show the answer: 1. Plain arch 2. Tented arch 3. Radial loop 4. Ulnar loop 5. Central pocket loop

Fingerprint taken from right hand. Hold up your fingers to show the answer: 1. Plain whorl 2. Central pocket loop 3. Double loop whorl 4. Accidental loop whorl 5. Radial loop

Fingerprint taken from right hand. Hold up your fingers to show the answer: 1. Plain whorl 2. Central pocket loop 3. Double loop whorl 4. Accidental loop whorl 5. Radial loop

Fingerprint taken from right hand. Hold up your fingers to show the answer: 1. Plain whorl 2. Central pocket loop 3. Double loop whorl 4. Accidental loop whorl 5. Radial loop

Fingerprint taken from right hand. Hold up your fingers to show the answer: 1. Plain whorl 2. Central pocket loop 3. Double loop whorl 4. Accidental loop whorl 5. Radial loop

You Do: Make a table of the fingerprints on the figure 12 handout. Identify the overall pattern of each print. Then, see if any prints match. Some will have multiple matches, others will have none. Letter Pattern Matches