>Such a condition obviously does not exist on Earth, so this feature could not have arisen via environmental pressures, at least not directly. Your premise doe

>Such a condition obviously does not exist on Earth, so this feature could not have arisen via environmental pressures, at least not directly. Your premise does not justify your conclusion. Reword your final sentence to read: Such a condition obviously does not exist on Earth, so this feature could not have arisen on Earth via environmental pressures, at least not directly.