Daphnia pulex are tiny aquatic crustaceans which have a translucent body which allows us to observe their internal organs in thorough detail. Daphnia is alleged to be a substitute of a human being in this experiment to examine the effects of chemicals on a heart of beings or other species for that matter . This will be measured by the heart rate as the heart rate is the contraction in one complete cardiac cycle. Furthermore Daphnia pulex is the most common species of water flea, an organism which can be found in almost every permanent, eutrophic water body. Generally Daphnia are freshwater organisms. In this experiment the Daphnia will be observed, checking the heart and circulatory system under low power magnification. Daphnia can be found
