The Tree-of-Life is a fictional plant (the ancestor of yams, with similar appearance and taste) in Larry Niven's Known Space universe, for which all Hominids have an in-built genetic craving. Consumption of Tree-of-Life makes human-related species turn into Pak Protectors, as a result of a symbiotic virus that grows in the root; however, the virus requires enough Thallium to develop, which is why it failed to grow on Earth. To those too young to develop into Protectors, Tree of Life smells repugnant, while the virus is fatal to those too old.
Search for life's beginnings: origin of life.(ORIGIN OF LIFE)(Genesis The Scientific Quest for Life's Origin)(Book review)
May 26, 2006; Genesis The Scientific Quest for Life's Origin by Robert Hazen Joseph Henry Press, Washington, DC, 2005. 359 pp. $27.95, C$37.95....