This research project focuses on the physiological requirements for invasions of the marine realm in vertebrates. Such invasions are relatively uncommon, most likely due to the differences in the physical and chemical conditions on land versus in water. Such differences require or favor different solutions to physiological challenges such as dehydration, thermoregulation, and salt balance as well as to other functions such as reproduction and locomotion. I have studied several distantly related animal groups that have each made independent marine invasions to determine the ways in which various vertebrates have overcome these challenges, mostly focusing on the role of body size.
This research has revealed the strict demands of the aquatic medium that have caused a variety of adaptions by tetrapods before and during their aquatic invasions. In most cases, one or many key innovations are required in order to make such invasions possible. Further, these findings suggest that broad-scale patterns of morphological evolution within higher taxa are often determined more by physiological constraints than by ecological interactions such as competition or sudden environmental fluctuations such as climate change.