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11/13/13

11/13/13. AIM: How was fingerprinting developed in forensic science? DO NOW: Are fingerprints individual or class evidence? EXPLAIN YOUR ANSWER. HOMEWORK: Textbook read 72-73 and 76-77(Anatomy of a fingerprint). What are friction ridges and where are they found?.

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11/13/13

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  1. 11/13/13 • AIM: How was fingerprinting developed in forensic science? • DO NOW: Are fingerprints individual or class evidence? EXPLAIN YOUR ANSWER. • HOMEWORK: Textbook read 72-73 and 76-77(Anatomy of a fingerprint). What are friction ridges and where are they found?

  2. DactyloscopyThe study of fingerprints Historically • William Herschel—required Indians to put their fingerprints on contracts, and also as a means of identifying prisoners • Henry Faulds—claimed that fingerprints did not change over time and that they could be classified for identification • Alphonse Bertillon—proposed body measurements as a means of identification; termed anthropometry • Francis Galton—developed a primary classification scheme based on loops, arches and whorls. • Edward Richard Henry—in collaboration with Galton instituted a numerical classification system • Juan Vucetich—developed a fingerprint classification based on Galton’s that is used in Spanish-speaking countries

  3. William and Will west

  4. Fingerprinting Recording or Making Prints • rolling inked prints • primary identification number Lifting Prints • Black, white and fluorescent powder • Chemicals—ninhydrin, iodine, silver nitrate, cyanoacrylate Other Types of Prints • Palm, lip, teeth, eye, ear, voice, shoe and footprints

  5. What is a fingerprint? • Skin has an outer layer (epidermis) which has ridges projecting inward, and an inner layer (dermis) which has projections pressing into the spaces between ridges • A fingerprint is a pattern made by the friction ridges, which is left behind due to sweat and oil that sticks to them. • Fingerprints form during the fetal stage of development.

  6. http://www.smithsonianmag.com/video/Where-Do-Fingerprints-Come-From.htmlhttp://www.smithsonianmag.com/video/Where-Do-Fingerprints-Come-From.html

  7. When do they form? • In early embryonic development & remain constant

  8. What determines fingerprints? • DNA - Genes • & environmental forces: pressures within the womb and contact with the amniotic fluid

  9. Formation of fingerprints • Skin layer growth • 3-4 month • Middle layer of skin buckles and folds creating the first ridges • Creation of ridges • fetus touches surrounding structures, exact position in the womb and the density of the womb's amniotic fluid determine how every individual ridge will form • Ridge patterns: 6 months • The ridges on a fetus's fingertips have formed three main patterns categorized as arches, loops and whorls • Fingerprint characteristics • two common characteristics found in every fingerprint: ridge end and bifurcation • The sequences of ridge end and bifurcation characteristics are different in every fingerprint

  10. Anatomy of Fingerprints • Epidermis • Outer layer of the skin • Dermis • Inner layer of the skin • Dermal papillae • Layer of cells between the epidermis and dermis • Responsible for determining the form and pattern of the ridges on the surface of the skin

  11. Fundamental Principlesof Fingerprints • A fingerprint is an individual characteristic. • A fingerprint will remain unchanged during an individual’s lifetime. • Fingerprints have general characteristic ridge patterns that permit them to be systematically classified.

  12. Thursday 11/14/13 • AIM: How are imprints individual pieces of evidence? • DO NOW: Explain how fingerprints are formed • HOMEWORK: Textbook read pages 79-80. Answer questions 6-10 on page 100 • Wednesday hw: Textbook read 72-73 and 76-77(Anatomy of a fingerprint). What are friction ridges and where are they found?

  13. DONOW ANSWER • DNA controls formation of epidermis and dermis • The pressure on the amniotic fluid finalizes the ridge pattern

  14. Fingerprint Ridges • Give skin traction for picking up items. • The fine lines curve, circle, and arch. • Valleys - grooves or furrows • Hills - friction ridges

  15. Fingerprint principle 1 • A fingerprint is an individual characteristic • no two fingers have yet been found to posses identical ridge characteristics

  16. Principle 2 • Fingerprints have general ridge patterns that permit them to be systematically classified

  17. Fingerprint Pattern • Pores on the ridges • Discharge perspiration from the sweat glands • Sweat mixed with oil can leave a latent invisible fingerprint

  18. Other Prints • Ears—shape, length and width • Voice—electronic pulses measured on a spectrograph • Foot—size of foot and toes; friction ridges on the foot • Shoes—can be compared and identified by type of shoe, brand, size, year of purchase, and wear pattern. Kendall/Hunt Publishing Company

  19. Other Prints Palm—friction ridges can be identified and may be used against suspects.

  20. Other Prints Footprints are taken at birth as a means of identification of infants.

  21. Other Prints Lips—display several common patterns • Short vertical lines • Short horizontal lines • Crosshatching • Branching grooves

  22. Other Prints Teeth—bite marks are unique and can be used to identify suspects. These imprints were placed in gum and could be matched to crime scene evidence.

  23. Other Prints The blood vessel patterns in the eye may be unique to individuals. They are used today for various security purposes.

  24. Friday 11/15/13 • AIM: how are fingerprints identified? • DO NOW: List the three major characteristics used to identify fingerprints. • Explain why each of your ten fingerprints are different.

  25. Characteristics of fingerprints

  26. Arch An arch has friction ridges that enter on one side of the finger and cross to the other side while rising upward in the middle. Types • Plain- the arch is mild • Tented- the arch is spiked upward

  27. Plain arch

  28. Tented arch

  29. Loop A loop must have one or more ridges entering and exiting from the same side it began. Loops must have one delta (a“Y” pattern from diverging ridges) Types • Radial--opens toward the thumb • Ulnar--opens toward the “pinky” (little finger) Which type of loop is this, if on the right hand? Left hand? deltaΔ

  30. Whorl A Whorl has a minimum of 2 deltas. Types • Plain- 2 symmetric deltas and a complete ridge circuit (circular in pattern) • Central Pocket- 2 asymmetric deltas, one side appears to be stretched • Double Loop- 2 loops and 2 deltas • Accidental- a whorl that does not fit the 3 above pattern types Plain whorl

  31. Central Pocket Whorl

  32. Double Loop (whorl)

  33. Accidental whorl

  34. http://on.aol.com/video/how-to-determine-fingerprint-patterns-72416331http://on.aol.com/video/how-to-determine-fingerprint-patterns-72416331 Kendall/Hunt Publishing Company

  35. White lines in ridge patterns represent diet pattern. • Many white lines indicate celiac disease

  36. Determining fetal environment • The more symmetrical your fingerprints the more stable the amniotic environment Kendall/Hunt Publishing Company

  37. Monday 11/18/13 • AIM: how are fingerprints analyzed? • DO NOW: 1- What are the 3 general fingerprint patterns? 2-Explain the roll of the delta in fingerprint identification HOMEWORK: Using the class information, create a bar graph of the % of fingerprint patterns 2- Do the classroom % match the national average? Kendall/Hunt Publishing Company

  38. Loops • Must have one delta

  39. Whorls: 2 deltas

  40. Arches NO deltas

  41. Human population fingerprint distribution • Loops: 65% • Whorls: 30% • Arches: 5%

  42. FINGERPRINT IDENTIFICATION • Table 4.2 Frequency of fingerprints • Loops Whorls Arches • Ulnar radial plain other plain tented • 60% 5% 20% 10% 4% 1% • loops = 65% whorl=30% arches =5%

  43. On your computer paper

  44. Thursday 11/21/13 • AIM: how are fingerprints compared? HOMEWORK:Textbookpg 100 questions 3-10. write out the question followed by the answer

  45. Identify each fingerprint pattern. ? A B Right Hand Left Hand C Right Hand E D Right Hand Left Hand

  46. Fingerprint Identification • The uniqueness of a fingerprint can be determined by the pattern of ridges and valleys as well as the minutiae points. • Minutiae points are local ridge characteristics that occur at either a ridge bifurcation or a ridge ending.

  47. Ridge Characteristics Minutiae—characteristics of ridge patterns • Ridge ending • Short ridge • Dot or fragment • Bifurcation • Double bifurcation • Trifurcation • Bridge • Island • Enclosure • Spur Kendall/Hunt Publishing Company

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