Bellringer • What do you think entomology is? Objective • Learn what entomology is and what the three types of entomology are. Forensic Entomology Entomology • What is entomology? • Entomology is the scientific study of insects!!! • EWWWW GROSS!!!! Background check • People come from all different backgrounds, so let’s see who knows what about insects. • On page 370 of the textbook take the quiz and test your knowledge of the insect world. (1-14) • Record your answers in your notes and in complete sentences so you can refer back later. Taxonomy • Taxonomy is the classification of things in an orderly way that indicates natural relationships. • This is how we sort different living creatures. Steps of Taxonomy • Largest (most general) category is Kingdom. The smallest (most specific) category is Species. Example What does this have to do with forensics? • Forensic Entomology is the use of insects and other arthropods to aid in legal investigations. • Arthropods are animals characterized by jointed legs, a segmented body, and a hard, nonliving exoskeleton. Bellringer • What are the three areas of entomology that forensic scientists are concerned with? Objective • Know the three processes of death The 3 general areas of forensic entomology • Urban entomology • Insect damage to structures • Stored products entomology • Insects infesting foodstuffs • Medicolegal entomology • Insects that inhabit human remains Forensic Entomology • Forensic scientists are mostly concerned with medicolegal entomology. • They commonly use it to the determine postmortem interval associated with the time of death. • Postmortem Interval is the time elapsed since a person has died. Check point • What is forensic entomology? • What are the three types of entomology? First • Before we can study how insects take over a person’s body once they are dead we must learn and understand the processes that happen after a person dies. The process of Death • First off, death is a process and not an event. • Cause of death is not the process of death. • Different tissues and organisms in a living body die at different rates. Determining the time of death • Most accurate if the body is found within the first 24 hours. • Use the three indicators • Algor mortis • Livor mortis • Rigor mortis • After these time periods have passed other methods must be used instead. • Estimations based on the environment and the scene. Algor mortis • Algor mortis refers to the cooling rate of the body after death. • Immediately upon death, the body can no longer metabolically maintain its temperature of 98.6 degrees Fahrenheit and begins to equalize its temperature to that of its environment. • Measuring the internal body temperature can give you some indication of the time of death. Newton’s Law of cooling • Newton was one of the best physicist ever. • Wrote an equation to predict the rate of change in the temperature of a body using the starting body temp and the air temp. Glaister Equation • Newton’s method doesn’t work well for dead bodies. • The Glaister Equation is used from 1 to 36 hours after death, but is most accurate within the first 12 hours. • 𝐻𝑜𝑢𝑟𝑠 𝑠𝑖𝑛𝑐𝑒 𝑑𝑒𝑎𝑡ℎ = 98.4℉−𝑖𝑛𝑡𝑒𝑟𝑛𝑎𝑙 𝑏𝑜𝑑𝑦 𝑡𝑒𝑚𝑝𝑒𝑟𝑎𝑡𝑢𝑟𝑒 1.5 Glaister Equation • Generally a body cools about 1 to 1.5 degrees Fahrenheit per hour until it reaches ambient temperature. • The temperature of the environment, type of clothing on the body, wetness of the clothing, air movement, # of layers of clothing, and other conditions must be taken into consideration. • Also, the greater the ratio of surface area to mass, as with children or smaller adults, the faster the body cools. Livor mortis • Livor mortis refers to the pooling of blood in the body due to gravity after the heart stops. • It appears on the skin as a purplish-red discoloration (like a bruise) and can give an indication of the position of the body at the time of death. Livor mortis • It begins within a half hour after death and is most evident within the first 12 hours • After 12 hours the discoloration will not move regardless of how the body is repositioned • This fact is useful when determining whether a body has been moved after death Rigor mortis • Rigor mortis is a stiffness in the muscles that occurs shortly after death. • Immediately upon death muscles begin to relax, but then some enzymes in your muscles begin to act and cause your muscles to become more rigid. Rigor mortis • Rigor mortis begins in the smaller muscles so it’s first observed in the face, neck and jaw. • The noticeable stiffness of rigor mortis can occur within a few hours after death and is gone within approximately 30 hours, leaving the body limp. Rigor mortis • Rigor mortis begins to disappear in the same order in which it began. • Rigor mortis is affected by the environmental conditions such as temperature, dehydration, condition of muscles, and their use prior to death • There are uncertainties in determining the time of death from rigor mortis Estimating Time of Death Temperature of Body Stiffness of Body Time Since Death Warm Not stiff Warm Stiff Cold Stiff Cold Not stiff Not dead more than 3 hours Dead between 3 and 8 hours Dead between 8 and 36 hours Dead for more than 36 hours Checkpoint • What are algor mortis, livor mortis, and rigor mortis? Reading Activity • Read pages 380 and 381 and then answer the following questions 1. What is autolysis and when is it first observed? 2. What is putrefaction and why is it so smelly? 3. What is mummification and why doesn’t it happen to every dead body? 4. What is digenesis? 5. What variables have the largest effect on the rate of decomposition? 6. How long would it take a body to become a skeleton if it was out in 45 degree Celsius weather? Case Study • Is it possible to stop a body from decomposing at all? • Read the case study on pages 381 to 382. “Colonel William Shy” • How was this possible? Tomorrow • Life cycle of Insects and the Insects of Death Bellringer •What is algor mortis and how is it different from livor mortis? Objective • Finish learning about the process of death • Learn how the life cycle of insects is used by forensic scientists to determine the time of death of a dead body. How’d we learn this? • Texas Body Farm: Caution…this is super gross!! • https://www.youtube.com/watch?v=OFJrow7yaec • What are the four steps of death in the video? Reading Activity • Read pages 380 and 381 and then answer the following questions 1. What is autolysis and when is it first observed? 2. What is putrefaction and why is it so smelly? 3. What is mummification and why doesn’t it happen to every dead body? 4. What is diagenesis? 5. What variables have the largest effect on the rate of decomposition? 6. How long would it take a body to become a skeleton if it was out in 45 degree Celsius weather? Decomposing Whale • Remember the process of death is not one step. • As a formerly living thing decomposes gasses are released inside the body which can create very large amounts of pressure. • Warning this video is disgusting…like really really gross… • https://www.youtube.com/watch?v=d2CfYOJ5oxk Objective • Use the life cycle of insects to solve crimes Life Cycle of Insects • Knowing the life cycle of insects can help forensic scientists determine how long they have been infesting a body. 1. 2. 3. 4. Egg – 12 hours Larva (maggot) – 4 days Pupa (Dark hard shell) – 3 days Winged Adult (Flies) – 12-24 hours Life Cycle of Insects • Two bodies are found in the same area. Which body has been dead longer? A. One that is found with flies on it but no signs of anything else. B. One that is found with flies on it and with empty pupae. Insects of Death Reading • Read pages 384 to 385, and then answer these questions. 1. What are the two most common insects found on corpses? 2. How many species of flies live on Earth? 3. In what order do flies arrive at a dead body? 4. Where do flies lay their eggs on a body? 5. Once fly eggs hatch what do they eat? 6. How do maggots raise the dead body’s temperature? 7. Where does most of the body's mass go? 8. Who takes over once the body dries out? 9. What percent of the original body weight is left behind by the end of the decay stage of decomposition by the insects? Body In The Basement • Read all of page 386 and then answer the following questions: 1. Why were specimens collected at the scene raised in the laboratory? 2. Why was data on climatic conditions gathered? Bellringer – Start New 1. What is algor, livor, and rigor mortis? 2. Fill in the chart: Temperature of Stiffness of Body Body Warm Time Since Death Not dead more Dead between Cold Stiff Dead between Not stiff Dead for more 3. What can you infer from find fly eggs on a dead body, but not finding hatched eggs. About 12 hours dead* Temperature of Body Stiffness of Body Time Since Death Warm Not stiff Warm Stiff Cold Stiff Cold Not stiff Not dead more than 3 hours Dead between 3 and 8 hours Dead between 8 and 36 hours Dead for more than 36 hours Objective • Answer questions to entomology video Quiz on Friday Scripts Preserving Body Parts! • Parts without muscles such as fingers can be preserved for many hours, while major muscle containing parts such as arms need to be re-attached and revascularized within 6-8 hours to have a viable limb. • Parts should be wrapped with moistened gauze and placed inside a clean or sterile bag floating in ice water. Forensic Entomology Video 1. After how many hours is entomology usually the best option to estimate the time of death of a body? 2. A sampling of which insects, and in what stages, should be taken back to the lab? 3. Why do forensic scientists preserve half of the larva they take back to the lab and keep half alive? 4. What other information does an entomologist need to know about the death site? 5. What two things do forensic scientists use to figure out the exact temperature of the crime scene for the time the body was there? Forensic Entomology • Part One: • https://www.youtube.com/watch?v=VeOt ScDxq6s • Part Two: • https://www.youtube.com/watch?v=Ov1t UK8r6sM Bellringer • What is algor mortis and how does it help forensic scientists determine the time of death? Objective • Be prepared for the quiz on Friday Quiz on Friday Answers 1. 72 hours 2. All insects found and in all stages 3. Preserve half so they know what it looked like when it was picked up (evidence). Keep half living so they can calculate how old it is and what specific species it is 4. Temperature, environment, clothing, etc. 5. Local weather information and temperature data collected at the sight for a couple of weeks after the body is found. Scripts Fingers • Fingers do not contain muscles (other than arrector pili). The muscles that move the finger joints are in the palm and forearm. The long tendons that deliver motion from the forearm muscles may be observed to move under the skin at the wrist and on the back of the hand. Other Uses of Insects • Maggots love wounds, so maggots can help point them out! • Insects can help place a suspect at the scene of a crime. • The suspect has a bite from a bug that is only from a certain area, but the suspect denies being there. • Contraband trafficking can sometimes be traced by identifying trapped insects that were not intended to be shipped. Other Uses of Insects • The species of insects plastered on an automobile radiator allowed investigators to refute a suspect’s alibi. • The presence of drugs in a body can sometimes be detected by harvesting and testing the feeding maggots. • In civil cases, insects found in stored food products or clothing can cause considerable discomfort as well as monetary loses. • Insects can also damage buildings • Termites and carpenter ants Case Studies • Read the case studies on page 402-403, then answer the following question: 1. How reliable can insects really be when determining the time of death of a body? Why should or shouldn’t it be used to convict someone of murder? Give three scientifically sound arguments to back up your opinion. Review Sheet Bellringer • What are two uses of insects found at a crime scene that do not have to do with estimating the time of death of the victim? Objectives • Prove you know the ins and outs of entomology. POP Test!!! • You may use your notes. • If I even think you’re cheating this time I will take your whole test and throw it out…that means you get a zero.