The Long and the Short of It: The Science of Life Span and Aging

"Potatoes live longer than kings," sighs ecologist Silvertown (An Orchard Invisible) in this whimsical book on aging. Aging is a complex topic, but the author mixes art, science, and humor to brew a highly readable concoction, presenting one aging theory after another. For instance, the "rate of living" hypothesis%E2%80%94live fast, die young%E2%80%94may be defunct, but Silvertown instills awe for the science that tried to make it work: researchers gauged the metabolism of water fleas by simply capturing them in jars, and counting the visible heartbeats in their near-transparent bodies. He also asks why postmenopausal women live longer than men. The latest studies say that in certain periods of human history, grandmothers who stopped reproducing channeled their energies and became useful secondary caregivers. But grandfathers who reproduced their entire lives apparently didn't feel pressured to become otherwise useful%E2%80%94and went "redundant." Indeed, reproduction comes with longevity tradeoffs throughout nature. But the ultimate answer to why we die likely has to do with Nobel Prize%E2%80%93winning immunologist Peter Medawar's casual observation that the aged make diminishing contributions to future generations. Silvertown's engaging tour through this enigmatic science ends wondering whether stem cell research will let us sidestep aging altogether. Who knows? (Nov.)