© 1999 Macmillan Magazines Ltd

Children of Prometheus: TheAccelerating Pace of HumanEvolutionby Christopher WillsPerseus: 1998. 310 pp. $25

Adrienne Zihlman

Books about human evolution tend to fallinto two categories: they either emphasizehow much like the apes we are in terms of ourmurderous, hierarchical or sexual behav-iour, or they elaborate the contrast betweenhairy, jungle-bound quadrupeds and ourbrainy upright selves. Christopher Wills, amolecular researcher, takes the second tack.In his view, we children of Prometheus havestolen fire, language and high technologyfrom the gods of things-as-they-are and haveevolved, and we continue to evolve so rapidlythat we have left our relatives, the chim-panzees, gorillas and orang-utans, in theDarwinian dust.

Although Wills acknowledges that humanand chimpanzee DNA are 98% identical, heis even more impressed by the degree towhich “our big-brained, clever-handed,highly social, language-speaking selves” haveoutpaced our hirsute relatives in the homi-noid Olympiad.

In support of his thesis that the rate ofhuman evolutionary change is accelerating,Wills recounts a number of case studies: howthe Tibetans have acquired physiologicaladaptations to high altitudes; how humanhaemoglobin variants confer resistance tomalaria; and even how one’s position in thehierarchy of the British Civil Service affectslongevity. He profiles the changing characterof Europe, with declining birth rates and ris-ing immigration that will mix gene pools andlead to increased diversity.

Turning from the human present to itspast, Wills reviews the latest versions of thehuman fossil record and concludes that thestory of the extinct and presumably less suc-cessful Neanderthals represents “the roadnot taken” by our own species. This judge-ment may be a trifle premature, as the Nean-derthals inhabited Europe and the MiddleEast for several hundred thousand years andHomo sapiens has been around for no morethan 200,000 to date. The extensive morpho-logical differences between Neanderthalsand modern humans is barely mentioned,but the DNA comparison reported last yearis recounted in entertaining detail.

Examining the earlier fossil record withan eye to ‘molecular-clock’ timing of thehuman–chimpanzee divergence to aboutfive million years ago, Wills ‘predicts’, as oth-ers have done, that the earliest hominids willbe chimp-like, and in fact australopithecinesvery much resemble bipedal chimpanzees.

Wills unquestioningly accepts Tim White’sclaim that his 4.4-million-year-old Ardip-ithecus ramidus is the earliest-knownhominid, although the lack of published evi-dence for the fossil’s bipedality has arousedconsiderable scepticism in the palaeo-anthropological community. Wills does notmention Meave Leakey’s more recent discov-ery in Kenya of Australopithecus anamensis,an undisputed hominid possessing limbbones that demonstrate bipedality four million years ago.

This book, though often interesting andinformative, seems to suffer from impreci-sion in the use of the word ‘evolution’ andfrom a lack of coherent focus. It is not alwaysclear whether Wills is referring to genetic,morphological or cultural evolution, as he

switches vertiginously from one to another.Sometimes his argument rests entirely at themolecular-genetic level (changes in gene fre-quencies in populations), and the morpho-logical level is omitted, as in the Neanderthalaccount. At other times, he abandons quan-titative molecular data and builds a homi-noid family tree from a motley array of phys-ical and behavioural features, “including theability to speak, the ability to recognize one-self in a mirror, the ability to walk bipedally,the degree of difference in size between thetwo halves of the brain, the amount of thumbmobility, the period over which the youngare nursed, the amount of skeletal musclestrength, the presence of breast in a non-lactating female, and a number of others”.

Wills concedes that chimpanzees are

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Prometheus unwoundbook reviews

Nineteenth-century artists such as Landseertend to be sentimental or sensational in theirrepresentation of animals. The 89 artists whosework is shown in Modern Wildlife Painting by

Nicholas Hammond (Yale University Press, $50,£35) aim to avoid the anthropocentric. Still,Chris Bacon admits this painting of a sandhillcrane symbolizes his own musings about life.

The meaning of wildlife

© 1999 Macmillan Magazines Ltd

stronger than humans, but deduces from hisanthropocentric items that human evolu-tion has occurred at about 10 times the rateof ape and monkey evolution.

How easy it would be to argue the con-trary from the chimpanzee point of view:that we are a most retrograde species whohave lost our body hair, facility in climbingtrees, female sexual swellings and numerousother primate assets. A more neutraldescription would merely state that we areadapted to a way of life very different fromthe ancestral one, and that small changes atthe molecular-genetic level can obviouslyresult in major phenotypic and behaviouralmodifications.

The mystery of the big human brain andwhat goes on inside it intrigues Wills, as it hasfascinated so many others.

The last few chapters, some of the best inthis book, deal with the genetic aspects ofdiseases such as narcolepsy, attention-deficithyperactivity disorder, schizophrenia,Alzheimer’s disease and the much-debatedfactors in IQ. He speculates that rapid gener-ational changes in microsatellite DNA —which are known to account for several neu-rological diseases, such as Huntington’schorea — could be a mechanism for intellec-tual improvement. In Wills’s opinion, ourgrandchildren will surely be smarter than us,and within a few generations Einsteins andMozarts will be commonplace.

These optimistic exegeses, while notwithout interest, illuminate by omissionhow little we understand about the molecu-lar, functional and adaptive factors that have

inflated the human cranium and its contentsthreefold over the past five million years.

In his last chapter, “Our evolutionaryfuture”, Wills unhesitatingly predicts an evenbigger-brained advent that will carry usbeyond the Solar System to planets of otherstars. I admire the courage of someone whocan make such projections for a society thatcannot predict the next election result or theweather next week.

Are we still evolving? This is the questionWills asks at the beginning and end of his vol-ume, and at many points in between. Theanswer is, of course, that we are: as are chimp-anzees, gorillas, orang-utans, crocodiles andbacteria. Are we really evolving much fasterthan those other organisms? Not at the mole-cular level, according to present evidence.Even bacteria, the oldest and most ‘primitive’forms of life, show a degree of flexibility intheir ability to survive and become resistantto our most potent antibiotics that our ownspecies has yet to prove it can match.

In Darwin’s concept of evolution, thedirection of evolutionary change is unpre-dictable, dependent as it is on changing con-ditions and the vagaries of natural selection.Wills’s confidence as to which evolutionaryfeatures are good or bad, superior or inferior,faster or slower, conveys perhaps a hint ofPromethean hubris.

For the future of the species, let’s hopethat our grandchildren will, as Wills predicts,be smarter than we are.Adrienne Zihlman is in the Department ofAnthropology, University of California, SantaCruz, California 95064, USA.

A most upliftingcareerOut of the Crater: Chronicles of aVolcanologistby Richard V. Fisher Princeton University Press: 1999. 178 pp.$24.95, £16.95

Steve Sparks

The life of an academic field geologist, espe-cially one interested in volcanoes, has consid-erable attractions. Pleasures to be foundinclude visiting beautiful and sometimesremote parts of the world, and enjoying thecompanionship of like-minded colleagues,the inevitable adventures and mishaps, andthe intellectual challenges of interpreting thetantalizing clues nature provides on how theEarth works. Richard Fisher, professor ofgeology at the University of California, SantaBarbara, is among the foremost volcanic geol-ogists of the second half of this century. Out ofthe Crater is essentially his reminiscences.

The book makes interesting and entertain-ing reading because of the richness of Fisher’sexperiences and the spectacular nature of hissubject. Each short chapter includes anec-dotes and descriptions of the parts of theworld he has visited, occasional explanationsabout the science of volcanology and someinsights into how he developed his scientificideas. The reader will be taken to some of theworld’s great volcanoes — such as El Chichónin Mexico, Vesuvius and Mount St Helens —and to diverse cultures: the American West,Argentina and China.

Fisher’s unique formative experience waswithin the context of a remarkable episode intwentieth-century history. In 1946, at 17 yearsold, he was stationed in the army at Los Alam-os and volunteered to go to Bikini atoll, wherehe observed the atomic bomb tests. Hisdescriptions of the Bikini tests are fascinating,and highlight the military authorities’ almostcomplete lack of understanding of the lethaland long-term effects of radioactivity. Toswim in the ocean at Bikini atoll a few daysafter the test now seems incredible.

What made the Bikini experience soimportant for Fisher’s later scientific achieve-ments was seeing the base surge phenomenon— the cloud of radioactive dust and waterdroplets that spreads radially along theground from the base of an atomic explosion.Fisher’s significant contribution to vol-canological science has been the elucidationof the geology of pyroclastic density currents,a term that encompasses volcanic base surges,pyroclastic flows and volcanic blasts like thatof Mount St Helens in 1980.

When volcanic base surges were first rec-ognized, Fisher realized the significanceimmediately. The enigmatic sedimentarystructures in many pyroclastic sequences,

book reviews

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This satellite image showsan unusual view of Mount StHelens and the area aroundit, 11 years after the 1980eruption. Winds of up to 440 kph flattened a widearea and lava fanned outfrom the volcano, leavingwhat is now a horseshoe-shaped crater, lower left,containing a lava dome 300 metres high. Faint tracesof green in the purple lavashow the regrowth ofvegetation, especially inprotected valleys. It is one ofthe many dramaticcomputer-generated digitalimages, obtained by satellitesensing systems, in Americafrom Space by Thomas B.Allen (Firefly, $29.95).

Blastfrom thepast