Euglena Gracilis Essay Example | Topics and Well Written Essays - 750 words

Euglena Gracilis - Essay Example Euglena Gracilis, the name comes from the Greek words eus and glne, i.e. good eyeball, which refers to the light-sensitive eyespot. Euglena gracilis uses its eyespot to locate light. This is a minute single-celled nutrient-rich freshwater organism of the genus Euglena, having the presence of chlorophyll, a reddish eyespot, and a single anterior flagellum. Euglena gracilis is just one of the many species of Euglena. Euglenas have spindle-shaped bodies, ranging in size from 1/1000 to 1/100 of an inch (0.025 to 0.254 millimeter) long. Most of the species are green in colour as they contain chlorophyll. Euglena produce food through photosynthesis for themselves, and also serve as primary producers for aquatic ecosystems. Some of the species also eat tiny particles of living matter. Euglena are interesting because they are a sort of combination of plant and animal. One the one hand they can make their own food like a plant, but they can also eat other things, like an animal. They can also swim and move. Scientists argued for years about which Kingdom to put them in, Animal or Plant Right now they are in neither; most scientists put them in the Protist Kingdom with other microscopic organisms, such as amoeba and paramecium. Three membranes surround the complex chloroplasts of Euglena. This is unlike chloroplasts of higher plants and most green algae, which are surrounded by two membranes. The additional membranes present a barrier to the import of chloroplast precursor proteins. Traditionally, the genus Euglena has been divided into several groups or subgenera depending mainly on morphological features of the chloroplast and paramylon and on cell rigidity. Euglena Gracilis also has a flagellum, a long hair-like thing, which is used by Euglena to swim. In this experiment we studied the growth of Euglena over a three week period. We took three jars and put the Euglena in each of them. We put rice in one jar and kept it in the dark. So this Euglena got its nutrients solely from the rice. Euglena in another jar was placed in the light with no rice, and this Euglena got its nutrients solely from the light. In the third jar we put rice and also placed this one in the light, so that this Euglena could get nutrients from both light and rice. Each week we checked on the Euglena jars to see which had the greatest exponential growth; From the experiment, we found that the Euglena in the light only did the best (results are summarized in table-1). Table-1: Growth pattern of Euglena over a three week period Jar-1 Euglena with Rice only (growth-cells per field) Jar-2 Euglena with Light only (growth-cells per field) Jar-3 Euglena with Rice and Light (growth-cells per field) Week-1 28 20 40 Week-2 22 31 35 Week-3 24 44 21 Conclusion It is amply clear that Euglena gracilis do behave like plants as well as animals, because when Euglena gracilis doesn't have enough light to make its own food, it looks for other things to eat. In this case rice supported the growth of Euglena. References: 1. Euglena, available online at http://www.fcps.k12.va.us/StratfordLandingES/Ecology/mpages/euglena.htm (Oct 24, 2006). 2. Woongghi Shin and Richard E. Triemer, "Phylogenetic analysis of the genus euglena (euglenophyceae) with particular reference to the type species euglena viridis", 759-770, available online