Tardigrades and rotifers are microscopic animals that are able to survive various extreme stressors. We are examining the effect of temperature change on the survival rate of these organisms. This will allow provide evidence indicating whether these two taxa developed cryptobiosis individually, or if it was inherited from a common ancestor.
In order to test our predictions on the development of cryptobiosis, we are taking 80 samples of each taxa from trees in various locations on the Michigan State campus. Lichen and moss will be scraped from trees and placed into a sealed envelope. The moss and lichen samples will be soaked in water, and then steeped to allow us to collect tardigrades and rotifers. 40 tardigrades and 40 rotifers will be placed directly into the freezer and then examined for survival, and 40 of each taxa will be placed in the fridge and then into the freezer. This will allow us to determine how the rate of freezing affects survival.
The rate of temperature change does not have a significant effect on the survival rates of both taxa. There is no significant difference between survivors from each taxa. This evidence supports the hypothesis that both tardigrades and rotifers inherited the ability to perform cryptobiosis from the same common ancestor. Conclusively, there is no significant difference between how tardigrades and rotifer are affected by these different freezing conditions. The next step would be to compare cryptobiosis in these two taxa with other variables being changed.