Biology Distilled Minimize Boom-And-Bust Cycles of Species Outbreaks and Ecosystem Imbalances

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“Serengeti Rules”), which he shows are appli- cable both to the restoration of ecosystems and to the management of the biosphere. The same rule may carry different names in different biological contexts. The double- negative logic rule, for instance, enables a given gene product to feed back to slow down its own synthesis. In an ecosystem the same rule, known as top-down regulation, NHPA/PHOTOSHOT VINCE BURTON/ applies when the abundance of a predator (such as lynx) limits the rise in the popu- lation of prey (such as snowshoe hares). This is why, in Yellowstone National Park in Wyoming, the reintroduction of wolves has resulted in non-intuitive changes in hydrology and forest cover: wolves prey on elk, which disproportionately feed on streamside willows and tree seedlings. It is also why ecologists can continue to manage the Serengeti, and have been able to ‘rebuild’ a functioning ecosystem from scratch in Gorongosa National Park, Mozambique. Carroll argues that the rules regulat- Interactions between predators and prey, such as lynxes and hares, can be modelled with biological rules. ing human bodily functions — which have improved medical care and driven drug dis- ECOLOGY covery — can be applied to ecosystems, to guide conservation and restoration, and to heal our ailing planet. His Serengeti Rules encapsulate the checks and balances that Biology distilled minimize boom-and-bust cycles of species outbreaks and ecosystem imbalances. Eco- Brian J. Enquist reflects on a blueprint to guide logical systems that are missing key regula- the recovery of life on Earth. tory players, such as predators, can collapse; if they are overtaken by organisms spread by human activities, such as the kudzu vine, a an biology become as predictive as the unification of biology ‘cancer-like’ growth of that species can result. physical sciences? And could it guide that has occurred in Some of Carroll’s recommendations are us in feeding the planet and reversing the shadows of more still being debated (see R. D. Grubbs et al. Cecosystem degradation, climate change and well known work such Sci. Rep. 6, 20970; 2016). Other pertinent species extinction? These are the overarching as that by Charles Dar- work, such as findings by evolutionary ecol- questions that organize evolutionary biolo- win, James Watson ogist Daniel Janzen on forest restoration, is gist Sean Carroll’s The Serengeti Rules — a and Francis Crick. already commonly used in conservation. compelling read filled with big, bold ideas. Through compel- Nonetheless, I suspect that many will find Biology is complicated. A cursory look at ling storytelling, key new insights and inspiration here. a diagram of the biochemical pathways in a insights of distant, The Serengeti Carroll has made a strikingly clear case that cell or interactions between predators and isolated biologists are Rules: The Quest ecology is a science on a par with molecular prey in an ecosystem reveals myriad net- brought to life. to Discover How biology and genetics. In many ways, this book works. Indeed, following the cascading effect Carroll finds the Life Works and is a homage to Charles Elton, who helped to Why It Matters of genes on a phenotype in or between indi- common thread in SEAN B. CARROLL define ecology as the study of species inter- viduals suggests that biological processes are discoveries in anat- Princeton University actions in a ‘trophic’ network shaped by the almost unfathomably complex and idiosyn- omy, physiology, gene Press: 2016. environment (see E. Marris Nature 459, 327– cratic. Over the past two decades, those study- regulation and cancer 328; 2009). Building on his vision, Carroll ing such systems have argued that most can be research. He does so by way of Nobel-prize- provides a passionate motto for the twenty- described as a network of interactions. How- winning molecular biologist Jacques Monod, first century: “better living through ecology”. ever, this analogy, although powerful, does Janet Rowley, ‘mother of chromosome genet- Are the Serengeti Rules a panacea? No, not necessarily tell us about the resilience of a ics’, and ecologists such as Tony Sinclair, but Carroll convincingly reveals them to be given system. Nor does it reveal the generali- who has helped to parse the ecology of the a sturdy foundation for the future of biology, ties of the natural world and the regulation of Serengeti region in Tanzania and Kenya. for human well-being, and for conservation genes, populations and ecosystems. Carroll distills this body of knowledge and management. ■ Carroll tells a richer story. He dispels the into principles. He argues that at all scales of idea that biology is organization, biology is regulated through Brian J. Enquist is in the department of too complex to gen- NATURE.COM axioms of interactions in networks — from ecology and evolutionary biology at the eralize or to become For more on science the number of molecules in our bodies to University of Arizona in Tucson, and is an the basis of a predic- in culture see: the numbers and kind of animals and plants external professor at the Santa Fe Institute in tive science. The book nature.com/ in and across ecosystems. He boils all of New Mexico. is really about the booksandarts biology down to six rules of regulation (his e-mail: [email protected]