Figure 5

The "trees" and "sponges" theme in biological organization. A) A California oak tree; B, C) Paragorgia corals (coral images courtesy of the National Oceanic and Atmospheric Administration (NOAA) [158]); D) Bronchial tree of the human lung (left half of the cast) and the airways with the pulmonary arteries and veins (right half of the cast) (image courtesy of the author of the cast, Dr. Walter Weber, Institute of Anatomy, University of Bern); E) Arterial system of the human lung (image courtesy of Julius H. Comroe, Jr. [159]); F) White sea sponge (image courtesy of NOAA [160]); G) The freshwater sponge, Spongilla lacustris (image courtesy of Kirt L. Onthank, Washington State University, WA); H) Coral Favites abdita (close up) (kindly provided by Hunterian Museum, ^©Hunterian Museum and Art Gallery, University of Glasgow); I) Scanning electron micrograph of alveolar tissue (image courtesy of Prof. Peter Gehr, Institute of Anatomy, University of Bern); J) Stereo pair of high-voltage electron micrographs showing the structure of the cytomatrix in a cultured NRK cell after rapid freezing (-185°C) and drying from the frozen state (-95°C) (reproduced with permission, ^©Porter, 1984. Originally published in The Journal of Cell Biology. 99: 3s–12s, [130]).