Forensic Science By: Garrett Dekan
A forensic scientist is a someone who uses their scientific training to help convict people who have committed crimes. They’ll assess the evidence at the crime scene and then present it in court.
Types of Forensic Scientists: • Forensic Anthropologists—analyzes human remains • Forensic Odontologists—examine teeth carefully • Forensic Pathologists—determines cause of death • Forensic Toxicologists—help with cases of poisoning and drug use • Forensic Entomologists—Studies insect evidence • There are also computer/digital specialists and pychologists
Determining Age: A forensic scientist first must collect the evidence without contaminating it. After collecting it they must analyze it. For example, forensic anthropologists will examine the remains of the body. They will check the growth rate of the bones. Ossification (bones become larger, thicker, and fuse together in teenage years) is a good guide to how old a child is. The collarbone is the last thing to finish growing at 28 years old, so it can also help to determine age. Anthropologists look for spikes on the vertebrae, the wearing of teeth, and joints with arthritis in elderly victims.
Determining Gender: Forensic scientists also try to determine gender. When they are determining gender they look at the skull and hip bones. When looking at the skull, they look at the ridges above the eyes, the bone just below the ear, and the occiput (bone at the lower back of the skull). They also look for the width of the hips because men’s hips are narrower than women’s because women’s were made for bearing babies.
Determining Height: Forensic anthropologists attempt to recreate the skeleton fromthe remains of the bones to determine the height. After recreating the skeleton, they must add four inches to the height for the missing tissue and muscle. They use longer bones to help estimate the height. For example, the height of a person is usually two and two thirds the length of the femur. However, height does also depend on the race and gender so it isn’t completely reliable.
Defects and Injuries: Some infectious diseases, poor diet, cancer, and birth defects, like spina bifida, can be seen in bones. Broken and mended bones are easily detected. Arthritis can occur from hard labor. Violent deaths can leave clues. Some examples are, a bullet wound leaves a round hole, a sharp weapon leaves chips in the bone, and fractures would indicate violence as well. Some fractures, however, can occur after the death, so the anthropologists have to be careful.
Fingerprints: There are three types of fingerprints. The first is visible fingerprints, which are visible. Visible fingerprints are prints left in grease, blood, ink, or other colored substances. Plastic fingerprints are also visible. They are prints left in soft substances like clay, wax, or soap. The last type of fingerprint is a latent fingerprint. Latent fingerprints are invisible fingerprints that are left by our body’s oils and greases. Fingerprint patterns are classified in three basic types: arches, whorls, and loops. Loops are lines that start on one side of the finger, loop around and then leave on the same side of the fingerprint as it started. Arches are prints that start at one side of the finger, make hills, then end at the other side of the finger. Whorl fingerprints are prints that make circles and don’t start or end on a certain side of the finger. Fingerprints, as you know, are different in every person. Fingerprints aren’t different because of the shape or pattern, but because of the ridge structure. About 200 million fingerprints are in the FBI Identification Division. Modern computer technology can be used to find a potential suspect in minutes. Loop Arch Whorl
DNA: DNA is made of guanine, cytosine, thymine, and adenine. You could describe DNA as a ladder that is curled around continuously with some 3 billion rungs attached to it. These rungs are arranged differently for everyone. A small part of the DNA strand is used for a person’s appearance, the rest of it is “junk”, but this “junk” sometimes helps a forensic scientist determine a person’s identity. The “junk” consists of small sequences of the base chemical called short tandem repeats or STRs. These STRs continually repeat from end to end. The number of times the STR repeats changes noticeably from person to person. Usually the STR only needs to be counted to thirteen before a match is made. Forensic scientists separate a DNA strand from the nucleus by using a mixture of chloroform and phenol. This typically isn’t enough DNA to analyze, so it is artificially increased by polymerase chain reaction or PCR. This method multiplies the DNA so it is big enough to be analyzed and used as evidence.
Court: DNA evidence can be very convincing if there is enough non-DNA evidence to support it. If, however, there is little to no additional evidence, then DNA evidence is basically useless, because of mistakes such as contamination. Analyzing DNA will hopefully progress more in the distant future. They’re hoping one day a single drop of blood will be able to determine the height, race, and maybe even the facial structure of that suspect. This will allow DNA evidence to be used as more reliable evidence in court.