Tardigrades

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The protozoan commonly known as the “water bear” is an extremophile that has engaged many in the scientific community. The Tardigrade is an invertebrate that has eight legs and comes in many shapes and sizes. This group has many adaptations such as cryptobiosis that allows it to survive in extreme environments. The Tardigrade can be found from land, to water, to sulfur springs, and to over 25 species found in the frozen tundra of Antarctica (Miller et al, 2001). To understand these creatures this paper will summarize the taxonomy, reproduction, food, and protective genetics, of the Tardigrades. The first section to this paper will examine is how these creatures are divided taxonomically. The “water bear” is a common name for a group of a little over 100 genera of protozoans grouped under the Phylum Tardigrada and is a relative of the Phylum Arthropoda. The phylum Tardigrada contains over 1000 species, and is grouped into three classes. There are two main classes the Heterotarigrada ad the Eutardigrada. The last is the Mesotardigrada and contains only one species, that was discovered in a sulfur spring in Japan 1937, and has not been seen since. “Water bears” are, as with most species, separated into groups by characteristics and more recently molecular genetic methods. The Heterotarigrada are known mainly for their hair like tufts on appendages and hard-undivided flattened scales. The Eutardigrada are known as “naked tardigrades” because they lack the hard scales or have several separate plates. Tardigrades are then divide further into orders by comparing groups for cuticle appearance, feeding tube, claws, and other defining features (Michalczyk, 2014). The tardigrade, due to the possibility of its habitat constantly changing,... ... middle of paper ... ...is first made through a biochemical pathway of using lipids and glyoxylating them. The trehalose allows the cells to be reduced to less than two percent water content. Trehalose is found in lower plants and protozoans and is comparable to sucrose in higher organisms. The most recent evidence shows that trehalose molecules interact with macromolecules and membranes of the cell and stabilize them during low water periods. Experiments have shown that cells membranes dried with trehalose once rehydrated resume normal functions. This is contrary to those without trehalose where biological functionality is lost. It is also believed that trehalose could be use in place of bulk water. These protective qualities allow for tardigrades to be revived many years after desiccation. In one case tardigrades were revived from a moss sample that was over 120 years old. (Crowe, 2014)
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