Tardigrades are so tough, they can survive outer space
So this is interesting:    It's not just the harsh environs of outer space that         
    tardigrades can survive in. The little critters seem adept 
    at living in some of the harshest regions of Earth. They
    have been discovered 5546m (18,196ft) up a mountain in the 
    Himalayas, in Japanese hot springs, at the bottom of the 
    ocean and in Antarctica. They can withstand huge amounts  
    of radiation, being heated to 150 °C, and being frozen
    almost to absolute zero.

I'm having a hard time seeing how the ability to survive in such high and low temperatures arose via natural selection, especially the ability to survive at near absolute zero while in the tun state. Such a condition obviously does not exist on Earth, so this feature could not have arisen via environmental pressures, at least not directly.