Wetlands are repositories of unique biodiversity. Wetlandorganisms are well adapted to their habitat, lying at theinterface of aquatic and terrestrial environments. In order tounderstand their adaptations in a better way, it is essential tograsp the basic properties of the medium in which variousorganisms live. This is attempted here by first examining theproperties of the two contrasting environments, terrestrialand aquatic. We focus primarily on locomotion, touchingupon related life processes like respiration, body size andmaintaining body balance by employing basic principles ofbiology and physics.