"Turner shows why drawing the boundary of an organism's physiology at the skin of the animal is arbitrary. Since the structures animals build undoubtedly do physiological work, capturing and channeling chemical and physical energy, Turner argues that such structures are more properly regarded not as frozen behaviors but as external organs of physiology and even extensions of the animal's phenotype. By challenging dearly held assumptions, a fascinating new view of the living world is opened to us, with implications for our understanding of physiology, the environment, and the remarkable structures animals build."--BOOK JACKET.