Date of Award

7-21-2005

Type

Thesis

Major

Biology

Department

Biology

First Advisor

Arthur Cleveland

Abstract

The process of cryptobiosis is characterized by a complete state of body water dehydration and undetectable metabolic activity, which allows tardigrades {Hypsibius) to escape environmental stress when conditions become unfavorable. In our research, Hypsibius was tested in a laboratory under pH levels of 3 to 10 and a salinity concentration gradient. In the pH experiment, we placed tardigrades in petri dishes with agar solution in an experimental pH and measured the average distance traveled. We expected them to respond favorably to a neutral pH of 7 which is common in most living organisms by showing increased movement. In the salinity experiment we placed the tardigrades in various salt concentrations and measured the number of organisms that were dead, alive and those that transitioned into cryptobiosis. We predicted that tardigrades will enter cryptobiosis in order to maximize their fitness under the most extreme conditions. Results obtained were significant in the salinity experiment, showing that as environmental conditions became more extreme, the rate of transition into cryptobiosis increased accordingly. These findings supported the proposed hypothesis that tardigrades will enter cryptobiosis in order to increase their survival rate in harsh environments, which will otherwise cause death. In contrast, the results in the pH range experiment were not significant. Tardigrades responded favorably and demonstrated increased movement in the pH range of 6 to 8, which leads us to conclude that they may be found in these types of soils.

Comments

Honors Thesis

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