Background Information

The Daphnia is in a class of animals called the crustacean class. This class also includes Crayfish. The Daphnia is barely visible to the naked eye, but it is very small, so you would not be able to examine it without a microscope. It has two long antennae; they are longer than their bodies. They use the antennae to jump from place to place, and to thrust themselves, therefore earning their name, water flea. There are many different types of Daphnia's, but we will be using the "Daphnia Magna" for our experiment. We chose the Daphnia because it's heart is visible, so we will be able to time the heart rate and compare it to a human's. In the animation above, you can see how visible the daphnia's heart rate is. When it gets hypothermia, its heart rate will grow rapidly, just like a human's. The Daphnia's main purpose is fish food, because their reproduction rate is extremely high, and they keep aquariums clean.

Hypothermia is a temperature-related disorder. Hypothermia is found usually when the shell of the body (skin) is shrunken to a 10% of a 70% kg mass. When this occurs there is nothing except for the core (inside of the body). There are four stages of hypothermia, impeding hypothermia, mild hypothermia, moderate hypothermia, and severe hypothermia. Impeding hypothermia is usually when the core of the body drops in temperature by 1-degree (97.6). When this happens the shell (skin) becomes numb and pale and muscles become tense causing them to spasm (shiver). Mild hypothermia is the first time when the human becomes a victim of hypothermia. Now the core temperature has dropped around two to three degrees (96.5-95.5). When this happens, the coldness becomes painful and the human becomes very uncoordinated. Moderate hypothermia is very bad and when this happens, a human must apply heat to various places around the body. Severe hypothermia is the worst of all of them causing the human to going into a state of unconsciousness. When this happens, the area in the body that produces heat goes into a state of thermogenisis. Some warning signs that a human has hypothermia are slurred speech, clumsiness, abnormal behavior, tiredness, disturbed vision, and usually results with collapsing.

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