Common senses

How does the human eye absorb vivid colour? C. U.M. Smith examines the biology of vision and the other major senses of hearing, smell, taste and touch in Biology of Sensory Systems . He reminds readers that while other organisms may not share with us the delights of Tate Modern, they live in their own very sensory world. Consider how vital it is for an insect to detect the direction of movement of its predator or for a deep-sea fish to find its way in the dimly lit oceans.

Smith begins by reviewing the building blocks and general features of sensory systems. Together with a very useful account of the evolutionary classification of organisms, this sets the scene for what follows.

In "Mechanosensitivity" the molecular genetics of C. elegans touch receptors is juxtaposed with the tactile receptors on mammalian skin; and the development of the tympanic organs (ears) of insects is outlined before turning to the evolution of the vertebrate ear, and the anatomy and physiology of the mammalian cochlea and auditory pathways. "Chemosensitivity" begins with a look at chemotactic movement in the bacterium E. coli . Chapters on taste and smell deal primarily with the cell and molecular biology of mammalian taste buds and odorant receptors but include short accounts of insect gustatory sensilla and the multiplicity of olfactory receptors revealed by Drosophila molecular genetics.

About a third of the book is devoted to photosensitivity. There is an engaging description of the variety of eye designs found in invertebrate phyla -from the pinhole eyes of some cephalopod molluscs to the compound eyes of arthropods. The in-depth coverage of the embryology and physiology of the human eye is followed by "variations on a theme" -how the eyes of other vertebrates are adapted to the lifestyles of their owners. Finally, there are chapters on thermo-sensation and pain, and a brief look at lesser-known senses.

The emphasis on comparative biology and evolution is one of the distinguishing features of this self-contained book. The other is the inclusion of a philosophical context. Philosophers' views of sensory modalities are alluded to throughout the text and brought together in the closing chapter that reviews the relationship between sensory neuroscience and philosophy. For undergraduates (and their tutors) taking courses in neuroscience, physiology, zoology, neuropsychology and evolutionary biology, this is an informative and thought-provoking text that incorporates questions to aid self-study. The book may also find a place on the shelves of postgraduates working, or simply interested, in the broad field of sensory biology.

Pauline Phelan is lecturer in cell biology, University of Kent at Canterbury.