Lab Report

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  • Topic: Cell, Microorganism, Bacteria
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  • Published : March 29, 2009
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Observing and Analyzing the Behaviors of Daphnia, Pill Bugs, Amoeba and Uglena Under Certain Experimental Conditions Testing Reactions to Gravity, Light and Food Jacob Kluth and Kelsey Jankowski


This lab has introduced the use of daphnia, pill bugs, amoeba and Uglena. We the AP Biology students were first introduced to the test subjects to test his or her capability of handling living organisms for upcoming science experiments. The AP Biology students were asked to create original experiments for all test subjects testing reactions to gravity, light intensity and reaction to food.

Daphnia, or Daphnia magna, are microscopic organisms in which the students created an original lab to test the reactions. These organisms come from the group daphniiade, which is also a part of the Cladocera, a group related to freshwater shrimp. Daphnia acquired is common name due to the erratic movements. Daphnia are small crustaceans that are also daphnids. These water fleas (as they are commonly referred as) closely resemble household fleas. Being arthropods, both share ancestry. Daphnids collect particles floating in water such as phytoplankton, vegetation and decaying organic material. These creatures reproduce by parthenogenicty or asexually. The offspring are identical to the parents and any difference in physical status is created from environmental conditions. Parthenogenesis appears to have evolved to let daphnids to obtain more food and temperature. Daphnia develop embryos that are often visible in the female’s body without the assistance of a microscope. These females can start reproducing as early as four days old and in intervals as often as tree days. This means that female daphnia can reproduce up to twenty-five times during her lifetime, though usually the number of offspring is far fewer. Daphnids have three main body parts, like most insects, the head, the thorax and the abdomen. In the head there is the brain, intestine, digestive caecum, compound eye, fornix and first antenna. The thorax includes the heart and shell gland among other organs. The abdomen includes the brood chamber and the ovary. Daphnia were use in this experiment because the organisms are easy to observe and daphnia respond quickly to changes in stimuli.

Pill bugs belong to the phylum arthropoda, the class malacostraca and the order isopoda. The pill bug’s anatomy includes the head, the thorax and the abdomen. Each pill bug has one major pair of antennae and one subtle pair, simple eyes, fourteen legs, seven segments on the thorax, paired appendages on the end of the abdomen called uropods and the color varies from dark gray to white both with and without patterns. The difference between females and males are that females have leaf-like structures attached to the base of each leg. These structures are what the females use to hold the eggs and embryos. Young pill bugs are identified by smaller size, different proportion and sexual underdevelopment. These isopods’ diets include decaying vegetation and other animals. Some may eat plants as well. Isopods actually breathe with gills, so the creatures are limited to moist conditions, such as under rocks or in soil. The pill bug’s predators consist of vertebrates and invertebrates. One behavioral trait includes rolling up into a ball when it feels as though it is in danger. Isopods have both positive and negative effects on the environments- they contribute minimal soil improvements and it is a food source to other organisms, but they can damage plants. Pill bugs were good for this experiment because they are easily identified and can be observed easily when different environmental factors are introduced.

The Amoeba is a tiny, animal-like, unicellular organism in the Protist Kingdom. Amoeba range in size from .25 mm to 2.5 mm. Amoeba live in fresh water (like ponds and puddles), in salt water, in wet soil and in animals (including people). Despite having various habitats, Amoebas are hard...
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