Biophysics is the application of physics and physical chemistry to biological systems. The field is often confined within the molecular biology realm, but it is equally valid at macroscopic scales when considering aspects of organism transport on land, in the atmosphere and in water.

Molecular biophysics addresses cellular physical chemistry such as interactions between DNA, RNA and protein biosynthesis, including regulation of these functions. Moreover, within this province are organism tissue studies including osmotic motion at the root/ soil interface;  stomatal gas exchange in plants; alveoli gas exchange in animals; and electromagnetic aspects of neuron. Technology used in molecular biophysics includes electron microscopy, x-ray crystallography, nuclear magnetic resonance and polarized light spectroscopy.

At a macroscopic level, biophysics is concerned with quantification of organism morphology and fitness. Thus, measurement of animal movement (velocity and acceleration) and body mass are fundamental in assessing fitness. Seed dispersal is concerned with the ability of seeds to achieve significant airborne buoyancy and range. The entire subject of animal flight is a valid subject of biophysics; moreover, the subjects of organism fluid buoyancy and swimming fitness are central in analyzing aquatic organism fitness.