One of the first things that happens after death is that the temperature in the body starts to drop. Before the temperature in the body core drops, a temperature gradient must be established from the outside to the core. After this gradient has become established the body temperature will drop with a theoretically predictably rate. This fact can be used to estimate time of death. Even if one succeeds in predicting when the temperature of the body core was 37 degrees Celsius, one has to remember that the time it takes to form the temperature gradient will vary from individual to individual, and will vary from almost no time, to over two hours. After the onset of putrefaction (about two days after death) the body temperature will increase again, due to the metabolic activity of the bacteria and other decomposing organisms. Rigor mortis is a well known phenomenon, and is due to a complex chemical reaction in the body. In the living body muscles can function both aerobic and anaerobic. In the dead body muscle cells can only function anaerobically. When muscle cells work anaerobically the end product is lactic acid. In the living body, lactic acid can be converted back, by means of excessive oxygen uptake after an anaerobic exercise.
The Term Paper on Reptiles Body Temperature
REPTILES: Reptile is a common name applied to the members of the Vertebrate class. This class includes snakes, lizards, turtles, crocodiles, and tuatara and other extinct species. Among all of the existing reptiles there are 2, 500 species of snakes; 2, 500 species of lizards; about 250 species of turtles; 22 species of crocodilians, and two species of tuataras. They are distributed throughout the ...
In the dead body this can not happen, and the breakdown of glycogen in the muscles leads irreversebly to high levels of lactic acid in the muscles. This leads to a complex reaction where actin and myosin fuses to form a gel. This gel is responsible for the stiffness felt in the body. This stiffness will not be over before decomposition begins. As rigor mortis is due to a chemical reaction, the reaction time is due to temperature and the initial concentrations of lactic acid. High metabolic activity in the time just before death, for example when running, leads to higher levels of lactic acid, and shorter time for the rigor mortis to develop. Higher environmental temperature also leads to a shorter reaction time. In temperate regions the following rules of thumb can be used in estimating death, but must be used with caution: Temperature of body Stiffness of body Time since death Warm Not stiff Not dead more than three hours Warm Stiff Dead between 3 to 8 hours Cold Stiff Dead between 8 to 36 hours Cold Not stiff Dead in more than 36 hours Rigor mortis should never be the only basis for estimating time of death. After death, a lot of internal organisms in the intestine will become very active.
Escherishia coli and others will start multiplying, and the decomposition begins. First the intestine and the blood will be attacked, and when gas formation and other things leads to rupture of the intestine other organs will be attacked. Organs starts decomposing at different times after death, and may also be used in estimating time of death. The decomposition of a body can be divided into several stages, even if the duration of each stage will vary a lot: Initial Decay The cadaver appears fresh externally but is decomposing internally due to the activities of bacteria, protozoa and nematodes present in the animal before death Putrefaction The cadaver is swollen by gas produces internally, accompanied by odour of decaying flesh Black putrefaction Flesh of creamy consistence with exposed parts black. Body collapses as gases escapes. Odour of decay very strong Butyric fermentation Cadaver drying out. Some flesh remains at first, and cheesy odour develops. Ventral surface mouldy from fermentation Dry decay Cadaver almost dry; slow rate of decay In the rest of this document we will focus on the telltale signs that insects can provide in the investigation of suspicous deaths. After the initial decay, and the body begins to smell, different types of insects are attracted to the dead body.
The Essay on Writers Life Line Time Death
A Comparison Between Shakespeare? s Sonnet 73 AndA Comparison Between Shakespeare? s Sonnet 73 And William Shakespeare, who lived during the second half of the 16 th century and the early 17 th century, wrote sonnets 73 and 12, both fourteen-line poems written to an anonymous lover. Similarly, the sonnets discuss the themes of time, love, and finally death. Both sonnets use A BAB rhyme, meaning ...
The insects that usually arrives first is the Diptera, in particular the blow flies or Calliphoridae and the flesh flies or Sarcophagidae. The females will lay their eggs on the body, especially around the natural orifices such as the nose, eyes(2), ears(2), anus, penis and vagina. If the body has wounds the eggs are also laid in such. Flesh flies do not lay eggs, but deposits larvae instead. After some short time, depending on species, the egg hatches into a small larvae. This larvae lives on the dead tissue and grows fast. After a little time the larva molts, and reaches the second larval instar. Then it eats very much, and it molts to its third instar. When the larvae is fully grown it becomes restless and begins to wander. It is now in its prepupal stage. The prepupae then molts into a pupae, but keeps the third larval instars skin, which becomes the so-called puparium. Typically it takes between one week and two weeks from the egg to the pupae stage. The exact time depends on the species and the temperature in the surroundings. A table of life histories to some species of blow flies and flesh flies are available here, and an illustration of the blowfly life cycle is available here.
The theory behind estimating time of death, or rather the post mortem interval (PMI for short) with the help of insects are very simple: since insects arrive on the body soon after death, estimating the age of the insects will also lead to an estimation of the time of death. How to estimate age of blowfly eggs, larvae, pupae and adults When blow flies oviposit, their eggs has come very short in their embryonic development. The eggs are approximate 2 mm in length. During the first eight hours or so there is little signs of development. This changes after that, and one can see the larvae through the chorion of the egg at the end of the egg stage. The egg stage typically lasts a day or so. The blowfly has three instars of larvae. The first instar is approximately 5 mm long after 1.8 days, the second instar is approximately 10 mm long after 2.5 days, the third instar is approximately 17 mm long after 4-5 days. Identifying the right instar is the easiest part, and is done relatively easy based on size of larvae, the size of the larva’s mouth parts and morphology of the posterior spiracles. The time it takes to reach the different instars depends very much on microclimate, i.e. temperature and humidity.
The Term Paper on Chicken Hatching Eggs Egg Day
Experiment: Chicken Hatching Background Information Some facts about chickens A chicken is a bird. One of the features that differentiate it from most other birds is that it has a comb and two wattles. The comb is the red appendage atop the head, and the wattles are the two appendages under the chin. These are secondary sexual characteristics and are much more prominent in the male. The comb is ...
At the end of the third instar the larva becomes restless and starts to move away from the body. The crop will gradually be emptied for blood, and the fat body will gradually obscure the internal features of the larvae. We say that the larva has become a prepupa. The prepupa is about 12 mm long, and is seen 8-12 days after oviposition. The prepupa gradually becomes a pupa, which darkens with age. The pupa which are about 9 mm in length are seen 18-24 days after oviposition. The presence of empty puparia should therefore tell the forensic entomologist that the person in question has been dead in more than approximately 20 days. Identification can be done based on the remaining mouth parts of the third instar larvae. A more precise way to determine age of larvae and eggs is the use of rearing. For example: the body is found with masses of eggs on it, none have hatched. How long time is it since the eggs was oviposited? Note the time of the discovery, note the time when the first 1. instar larvae occur. Subtract the first occurrence time with the discovery time, call this time A. Rear the blow flies to adults, let them mate, let them lay eggs on raw beef liver under conditions similar to the crime scene, take the time from oviposition to the first occurrence of 1.
instar larvae. Call this time B. By subtracting B-A, one gets C, which is an estimate of the time since oviposition to discovery. Similar calculations can be done for other instars as well. If one has good base-line data from before under different temperatures and for different species, one only needs to rear the flies to a stage where they can be identified, and that is the third stage or the adult stage. One important biological phenomenon that occurs on cadavers are a succession of organisms that thrive on the different parts. E.g. beetles that specialize on bone, will have to wait until bone is exposed. Predatory rove beetles or parasites that feed on maggots will have to wait until the blow flies arrive and lay their eggs. The succession on cadavers happens in a fairly predictable sequence and can be used in estimating time of death if the body has been lying around for some time. Here is a table over a succession experiment on guinea pigs performed by Bornemizza in 1957. There are several things to note about this table: The first groups to arrive is blow flies, followed shortly by staphylinids. As putrefaction develops, more groups arrive at the scene, with most groups present just before the body is drying out due to seepage of liquids.
The Essay on The Groundhog Speaker Death Dead
The Groundhog In Richard Eberhart s poem The Groundhog, the speaker analyzes the death of a groundhog. The groundhog, described as lying dead and maggots eating away at its flesh, is used by the speaker to show an understanding of life. Through the metamorphosis of the dead groundhog, the speaker portrays death and its cruelty. The speaker, once filled with happiness, transforms into a state of ...
After the body is drying out, dermestids, tineids and certain mites will be the dominant animal groups on the body, and blow flies will gradually vanish. Note also how the fauna changes in the soil. This can also be used to estimate time since death. Succession data can be incorporated in a database, and when the forensic entomologist investigates a case, he can use the taxa found on the body as input, and get an estimate of the time of death as output. The hypothetical table above shows the presence (1) and absence(0) of five different taxa (A, B, C, D and E) over ten days. The tabulated data is usually obtained from decay studies done on pigs or other animals. Let’s say the investigator finds taxa C, D and E on the remains. From the table above, we can see that taxa C occurs on the cadaver from day 5 to day 10, and taxa D from day 7 to day 9, and taxa E from day 9 to day 10. By studying the overlap, the entomologist estimate the PMI to be about 9 days. Several insects are specialized in living in very decayed dead bodies. One example is the cheese skipper, Piophila casei, where the larvae usually occurs 3-6 months after death. The cheese skipper is a well known pest of cheese and bacon worldwide, and has a cosmopolitan distribution.
Adult cheese skippers may occur early after death, but larvae occurs later. The earliest observation on human remains are when the body is two months, and this was under excellent summer conditions. In 1898, Potter examined 150 graves, and found remains of P. casei in ten of them. These graves were from three to ten years old and three to six feet deep. In temperate regions dead bodies often appear in spring, after the snow is gone. The forensic entomologist and the forensic pathologist must then try to determine whether the death occurred during the winter or before the snow set in. If the death occurred before November, it is possible to find dead insects in and on the body. By analyzing the dead insect fauna, and estimating when the insects probably died (this can be found by looking at meteorological records).
The Essay on True Philosopher Body Death Socrates
George Waszczuk 9/25/2000 Wed: 6: 30-9: 30 pm Phaedo Summary Socrates stands now before his disciples telling them he is not afraid of dying because he says death is what the true philosopher waits for all his life. The philosopher must have lived a good life, and when death is presented upon him, he should take the opportunity. Socrates formed a conclusion that: "That the real philosopher has ...
Another hint is when the different adults stop flying before the winter. For example: here in Norway, we have had some cases where the bodies have been found in the spring. In one case we found dead third stage blow fly larvae in the back of the mouth. The blow fly larva was of an species that is flying from May to October. It was from this concluded that the eggs probably was laid during October, and since it was relatively few larvae, probably late in October. In another case, we found several live insects on a dead body, and also many dead third stage larvae. The dead larvae was found on the stomach, the arms, the shoulders, and inside the head. We concluded that the live insects had colonized the dead body in the spring, and that the dead larvae had died during the winter. Based on the widespread occurrence of the larvae, we had to say it was likely that the body was colonized before October, probably in September. If the death occurred in the winter things become difficult in outdoor settings, as very few insects are active in the winter. It is reported that larvae of the winter gnat, Trichocera sp. can develop on carrion in the winter. By estimating the age of these larvae, if present, it could be possible to estimate the PMI.
Poison can be traced in blood, urine, stomach contents, hair and nails. One other important source is maggots occuring on a corpse. After a while it will be impossible to sample stomach contents, urine and blood from the dead body, but it will still be possible to sample from maggots, empty puparia or larval skin cast. The following list of chemicals has to my knowledge been traced in maggots: Many of these chemicals will also influence the life-cycle of the maggot. For example will high dosages of cocain accelerate the development of some sarcophagids. Malathion, an insecticide, is commonly used in suicide, and is usually taken orally. Presence of malathion in the mouth may lead to a delay in the colonisation of the mouth. Presence of amitriptyline, an antidepressant, can prolong the developmental time with up to 77 hours, at least in one species of Sarcophagidae. Knowledge of drug use in the victim is therefore important not only in finding the death cause, but also in estimating the time of death. The sites of blowfly infestation on the corpse may be important in determining the cause of death, or at least in reconstruction of events prior to death. For example: if there have been trauma or mutilation of the body prior to death, this may lead to heavy infestation of other body parts than the usual sites when the victim is not mutilated.
The Essay on Dead Man Walking
Imagine yourself convicted for a crime and sentenced to death. Imagine the hate in the society towards you. What kind of a soul would you have? How would you feel about the thought knowing when you are going to die and in what way? How will you react? Who will help you out? In the novel Dead Man Walking, Sister Helen Prejean, was asked to correspond with Pat Sonnier, a man sentenced to die by ...
Under a knife attack, it is usual to guard oneself with arms in front of thorax and head. This may lead to injury on the lower part of the arm. After death, blowfly may oviposit in these wounds. The usual sites of oviposition on dead humans are natural openings. Even here there is preference. Blowflies will most often lay their eggs in the facial region, and more seldom in the genitoanal region. If there is a sexual assault prior to death, leading to bleeding in the genitoanal region, blowflies will be more likely to oviposit in these regions. Therefore, if there is observed blowfly activity in the genitoanal region, one can start to suspect a sexual crime. This must of course be corroborated with other evidence as well. The interpretation of maggots in the anogenital region becomes very fuzzy after a few (4-5) days, as eggs will be oviposited in this region during the course of decay in the natural course of decomposition.
