The Shape of Life: An Underappreciated Video Series


Nature videos such as the Blue Planet specials and David Attenborough's many fine series are rightly appreciated for their excellence and interest. A series that is, in my opinion, regrettably overlooked is The Shape of Life: Animal Life as You've Never Seen it Before, produced in 2001 by Sea Studios Foundation (http://www.seastudios.com/). It is available in DVD format, and occasionally shows up on PBS at 4 a.m., but hardly anyone I know has actually seen it. Perhaps this is because it is more science-based than the typical nature series, exploring details of anatomy, paleontology, and genetics that are usually overlooked in nature programming.


Based on a book of the same name by evolutionary biologist Rudy Raff (Raff, 1996), Shape explores the eight major animal phyla into which biologists classify the majority of living organisms: sponges, cnidarians (jellyfish, hydras, and anemones), flatworms, segmented worms, arthropods (crustaceans, insects, spiders, and so on) mollusks, echinoderms (sea stars, urchins, sea cucumbers, and crinoids), and chordates (vertebrates like us, and our nearest invertebrate relatives). Each phylum has a distinct organization ("body plan") that characterizes all its members. Fossil evidence indicates that these distinct plans (around 35 in total) have existed for at least half-a-billion years, and formed the basis for the great diversity of life we observe on earth today. Despite several periods of mass extinction since that time, no new phyla have appeared. All the disparate organisms that arose following the mass extinctions evolved from one of the existing phyla and retained their basic design. This is quite remarkable. No phylum is either better or worse, higher or lower, than any other. They are independent, highly successful, solutions to the problems of living on earth.


The eight Shape of Life programs each examine one of the major animal phyla and the aspects of its body plan that make it both unique and successful, using stunning photography of living representatives and high-quality computer animations. Among the highlights are a computer-generated roller-coaster ride through the body of a sponge, and video footage of sea anemones fighting over territory; the slow-motion social behavior of sea stars through time-lapse photography; and a rock crab trying to break open a leafy hornmouth snail and failing, showing why its shell-leaves are such an important defensive adaptation. There is also an ingenious demonstration of how the swimming movements of jellyfish (sea jellies) contribute to their feeding. You also get to meet a variety of research scientists, from developmental biologists to geneticists and paleontologists, and to hear them rhapsodize their favorite organisms. Yes, even sponges and worms have their ardent admirers!


Uniting the eight episodes is the theme that the phyla are united by evolution from a common ancestor, a currently unknown proto-sponge that existed more than half-a-billion years ago; and that some of the simpler phyla first "invented" features such as multicellularity, muscles and nerves, and a brain and directional sense organs, that were then inherited by the more complex phyla. The specific details of the relationship between the phyla is left unspecified, because there is currently no scientific consensus on how they are related, and how one might have evolved into another (Nielsen, 2001; Valentine, 2004). Because the focus of the series is on the adaptive aspects of the body plans, the evolutionary theory underlying the program is not explained in great detail. The Shape of Life could usefully be viewed in conjunction with the PBS series Evolution: A Journey into Where We're From and Where We're Going, particularly episode 2: Great Transformations, which does explain the theory in greater detail.


Although science-based, The Shape of Life contains extensive footage of organisms in nature, and maintains the high production standards of the best nature programs. Many of the organisms shown, or ones much like them, can be seen along the Oregon coast. The science content is not overwhelmingly technical, so no fan of nature programs should feel reluctant to view it. The Shape of Life is anything but boring, and the ideas and themes it presents are important to understanding the world we live in.


Terry Morse

January 2005


Availability


The Shape of Life videos can be purchased from PBS (http://www.shoppbs.org/home/index.jsp) or from on-line booksellers, such as amazon.com. The 115 page companion book is currently out of stock on the PBS website, but is available from on-line booksellers. There is also a Shape of Life website (http://www.pbs.org/kcet/shapeoflife/) with supplemental information, activities, and teacher resources.


The Evolution videos and a companion book are also available from CRSN and PBS. A website with supplemental information and resources for teachers and students can be found at http://www.pbs.org/wgbh/evolution/.


References


Nielsen, Claus. 2001. Animal Evolution: Interrelationships of the Living Phyla, 2nd ed.


Raff, Rudolf A. 1996. The Shape of Life: Genes, Development, and the Evolution of Animal Form. Chicago: University of Chicago Press


Valentine, James W. 2004. On the Origin of Phyla. Chicago: University of Chicago Press.


Additional sources, many less technical than the ones mentioned here, are listed at http://home.teleport.com/~tmorse/Pages/Macroevol.html.