Down To Earth December 31, 2001 55 THE EVOLUTION EXPLOSION: HOW HUMANS CAUSE RAPID EVOLUTIONARY CHANGE· Stephen R Palumbi·W W Norton & Company·New York·pp288·US $24.99
harvard scientists have a place in the sun when it comes to biology. And with mentors like E O Wilson, the university faculty has a particularly tough act to follow. Stephen Palumbi a professor of biology and a relative newcomer to Harvard has, however, overcome any such limitation to produce a brilliant follow-up to Wilson's work. The book convinces that evolution is a fact, not a theory: a process that may manifest its effect in a few generations rather than spanning millions of years. By manipulating genes and rewriting the laws of natural selection, human actions have accelerated the evolutionary game. This is particularly evident among the species that live close to us, the animals we domesticate or devour, the pests that share the food we grow, and the microbes that surprise us by rapidly changing the very nature of the disease they cause.
Last few decades have made it amply clear that evolution can take place much more rapidly than Darwin ever imagined. Ever since penicillin was introduced in 1943 and declared a silver bullet, humans have haphazardly used antibacterial agents in soaps, face washes, cosmetics and even drugs, unaware that the war against bacteria was only just beginning. For most part, therefore, the author talks on the microbial evolution: the aids virus, the bacteria that cause tuberculosis and others responsible for some common infections.
The book begins with a trip to Hawaii to secure some rare snails for captive breeding - a process that entails an evolutionary pattern that is different from the one taking place in a natural habitat. Study of this human-driven evolution enables Palumbi to look into the wider issue of bacterial resistance to antibiotics. It is observed that antibodies are not enough to contain the bacteria that invade our bodies and ultimately evolve to prosper. These strains of bacteria arise only a few years after a new antibiotic is released and vary from one to 36 in number. According to Palumbi, using multiple antibiotics can be an effective strategy in tackling this problem. More dreadful, however, is the impact of the aids virus which is also mutating with time to develop resistance to the latest cocktail of drugs. The evolution of the aids virus becomes the focal point of this engaging work as the microbe is changing its form with amazing alacrity to defeat all human endeavours aimed at countering its attack. Palumbi also talks of pests that have evolved to survive pesticides of many kinds. Discussion of these creatures is pertinent here as they threaten crops around the world in a time of ever-increasing scarcity. The author shows how it is not enough to spray our fields with pesticides or virulent micro-organisms (biopesticides). Inevitably, the pests will evolve to flourish in the new pesticide-filled environment just as antibiotics are not enough to contain the bacteria that strike human bodies.
In other words, at the centre of this change is the "evolutionary engine" that is continually at work, adjusting organisms to their environments. Change the environment of an organism and the organism changes to keep itself fit a never-ending phenomenon that frustrates human efforts to eradicate harmful pests and deadly diseases. Human efforts to combat the scourges of field and body are now seen as just one half of the predator-prey, parasite-host phenomenon of co-evolution. All this, Palumbi writes, is "evolution with teeth". Whether we can survive our own power to reshape the earth remains an open question. But, he concludes, ideas evolve too, so that we can hope against hope to think our way back to more or less normal cycles of evolutionary change.
Well-written and provocative, the book makes for a useful start in new evolution syndrome. En route to bringing us up to speed on rapid evolutionary change, Palumbi sets some sort of record for the use of colourful language.
Anyone seeking an eloquent explanation of recent evolution as it relates to human impact from the use of herbicides, pesticides and antibiotics to aids treatment and genetic manipulation should find "The Evolution Explosion" a worthwhile read.
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