Tardigrade Research Paper

Introduction

Tardigrada, aka the Tardigrade is potentially the toughest animal on earth. They can be found almost anywhere - the top of the himalayas, japanese hot springs, deep ocean trenches, from polar regions to the equator. They make their homes in dunes, beaches, soil, lichens, mosses and marine and freshwater sediments. These tiny 1mm long extremophiles have been found to withstand the pressures of the deepest ocean trenches, mass amounts of radiation, and being heated to 150 degrees fahrenheit to being frozen to near absolute zero.

Conditions of Environment

The deep sea has many factors that make it difficult to live in. These being the amount of sunlight, or lack thereof, making photosynthesis impossible, the extreme pressures,

They have stylets which allow them to pierce plant cells and animal body walls. They have a sucking pharyngeal bulb which allows them to ingest food. They are also known to eat entire live organisms. Female Tardigrades will lay 1-30 eggs at a time, and these eggs are light enough to be carried by other animals for great distances, spreading the population. Fertilization can occur through a gonopore or the male can deposit his sperm on the eggs after they have been laid. Tardigrades can reversibly suspend their metabolism, slowing it to 0.01% of their normal rate. This deathlike state enables them to survive without

In the 1920's P. G. Rahm discovered tardigrades were able to withstand being heated for a few minutes in 151 degrees Celsius and survive being chilled for days in temperatures up to minus 200 degrees Celsius. While in this state the organisms are also resistant to radiation, Raul M. May from the University of Paris found that 570,00 roentgens were required to kill 50% of exposed tardigrades (only 500 roentgens would be fatal to a human). Water bears are also resistant to vacuums. Specimens exposed to high vacuum and electron bombardment in a SEM for 0.5 hours were then revived and survived for a few minutes before dying. Why are organisms in the cryptobiotic state able to withstand extreme conditions? Crowe (1971) hypothesized that the importance of water, heat, and oxygen in destructive reactions may explain why the lack of at least one of these characters in animals in cryptobiosis provides resistance to such cellular