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No. 14: Winter 1981 Supplement

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Worms with inside-out stomachs

The recently discovered tube worms, living near the hot water vents on the ocean bottom off the Galapagos, have no mouths or guts. Their bodies are covered with thousands of feathery tentacles, each packed with blood vessels. Apparently, the tube worms extract nutrients directly from the sea water and expel wastes the same way -- having in effect external stomachs. These worms, which may be many feet long, contain enzymes that permit them to extract carbon dioxide from the seawater and fix it much like plants do during photosynthesis. George Somero, at Scripps, estimates that the enzyme levels in the worms are similar to those in a spinach leaf.

(Anonymous; "15-Foot Sea Worm Has Plant Qualities," San Diego Evening Tribune, May 22, 1980. UPI dispatch)

Comment. This curious biological anomaly developed in an ecological niche where the primary energy source for sustaining life is geothermal rather than solar. How did this remarkable situation arise? Do the tube worms have relatives in the fossil record showing a step-by-step development of inside-out stomachs?

From Science Frontiers #14, Winter 1981. 1981-2000 William R. Corliss