Daphnia

             Homeostasis is when homeothermic organisms maintain a relatively constant body temperature. Organisms do this by using receptors in the brain to detect the temperature of the blood that passes through it. When the temperature of the blood rises a message is sent to the nervous system to stimulate sweat glands in your skin. This is a cooling effect and the body temperature falls. A decrease in body temperature also will result in a decrease of sweating or an increase in activity or shivering to try and increase the body's temperature (Campbell et al, 2003).
             II. Hypothesis.
             The increase in water temperature will increase heart rate of the Daphnia and the decrease in water temperature will decrease the heart rate of the Daphnia.
             Adding epinephrine to the water will increase the heart rate of the Daphnia. .
             III. Materials and Methods.
             Using a microscope the heart rate of a Daphnia is measured. Three .
             different sets are taken, each in fifteen-second intervals, for room temperature water, zero degrees Celsius water, and forty-five degree Celsius water. Then epinephrine is added and the heart rate is taken the same way, before epinephrine, after epinephrine, and with epinephrine. All of the results for each different time are then averaged together. For a complete description of the materials and methods used see the General Biology Study Guide (Erdahl et al, 2004).
             IV. Results.
             HEART RATE VS TEMPERATURE EXPERIMENT.
             Temperature: Trial 1 Trial 2 Trial 3 Average.
             0 28 28 28 28.
             22 25 34 33 31.
             45 40 37 41 39.
             The heart rate for the Daphnia at zero degrees Celsius was twenty-eight beats per fifteen seconds. At twenty-two degrees Celsius the heart rate was thirty-one beats per fifteen seconds. At forty-five degrees Celsius the heart rate was thirty-nine beats per fifteen seconds.
             EFFECT OF EPINEPHRINE ON HEART RATE.
             Trial 1 Trial 2 Trial 3 Average.
             Before Epinephrine 33 34 32 33.
             With Epinephrine 58 50 58 55.