In the teaching course of Physiology (from Greek φύσις, physis, "nature, origin"; and -λογία, -logia) the mechanical, physical, and biochemical functions of living organisms will be investigated. Physiology has traditionally been divided between plant physiology and animal physiology but the principles of physiology are universal, no matter what particular organism is being studied. The field of animal physiology, in particular, extends the tools and methods of human physiology to non-human animal species. The teaching course of Physiology will concentrate on understanding how physiological traits changed throughout the evolutionary history of animals.