In Brief

nis, both of whichhad beaks rather thanteeth. The latter crea-ture was especiallymodern- looking ,possessing a “keeled”breastbone similar tothose found in birdstoday.

Both birds weremore advanced thanArchaeopteryx, whichhas generally beenrecognized as the firstfeathered bird (al-though it may havebeen a glider ratherthan a true flier) andlived about 145 mil-lion years ago. Ar-chaeopteryx was notthe ancestor of mod-ern birds, as sometheorists have sug-gested, but was anevolutionary deadend, Feduccia asserts.The true ancestors ofbirds, he speculates,were the archosaurs,lizardlike creaturesthat predated dino-saurs and gave rise toArchaeopteryx as wellas Confuciusornis andLiaoningornis.

Two paleontolo-gists who vehementlyreject this scenario are Mark A. Norelland Luis M. Chiappe of the AmericanMuseum of Natural History; they wrotea scathing review of Feduccia’s newbook for the November 21 issue of Na-ture. Feduccia and his colleagues “don’thave one shred of evidence,” Norell con-tends. The fossil bed in which Feduccia’steam found its specimens, he remarks,has been dated by other researchers at125 million years, leaving plenty oftime for the birds to have evolved fromArchaeopteryx or some other dinosaur-like ancestor.

Chiappe notes that the anatomical ev-idence linking birds and dinosaurs is ac-cepted by the vast majority of paleontol-ogists. He does not dispute Feduccia’scontention that many of the dinosaursidentified as having birdlike features oc-curred in the Upper Cretaceous, well af-ter birds were already established. Butthat fact, Chiappe explains, in no wayundermines the notion that birds de-scended from dinosaurs—any more than

the persistence of primates into the pres-ent means that they could not have giv-en rise to humans. Moreover, he adds,dinosaur fossils from earlier periods aresimply less common.

Ironically, just two weeks before thepaper by Feduccia and his co-workersappeared, Science published a short newsstory on a fossil from the same site innorthern China—and thus the sameepoch—as the birds described by Feduc-cia’s group. But this fossil bolsters thebird-dinosaur link—at least accordingto Philip J. Currie of the Royal TyrrellMuseum in Alberta, Canada, who hasanalyzed it.

The fossil shows a turkey-size, biped-al dinosaur with what appear to be“downy feathers” running down itsback. The finding lends support to thenotion that feathers originated as ameans of insulation for earthbound di-nosaurs and only later were adapted forflight. Currie and several Chinese scien-tists have written a paper on the fossil

News and Analysis18 Scientific American February 1997

Evolutionary MakeoversMany insects, fish, birds and reptilesadapt their looks to new surroundingsand seasons: when the African butterflyBicyclus anynana is born during therainy season, for example, it sports eyespots to scare off predators, but genera-tions born during drier times do not.How different are these animals? Scien-tists from the University of Wisconsin atMadison, the University of Leiden andthe University of Edinburgh have dis-covered that it takes the presence ofvery few genes—half a dozen or so—tovary an animal’s appearance radically.The find helps to explain the astound-ing array of biological diversity.

Elephant Man’s Real DiseaseJoseph Cary Merrick, the famous Victo-rian known as the Elephant Man, proba-bly did not have neurofibromatosis, the

condition mostcommonly referredto as ElephantMan’s disease. Radi-ologists at RoyalLondon Hospital,where Merrick livedand his bones re-main, have nowsubstantiated thetheory that, in-stead, he suffered

from a rarer disorder called proteus syn-drome. Recent radiograph and CT scansof Merrick’s skull revealed characteris-tics of the noninherited disease, causedby malfunctions in cell growth.

Holey MicrochipsPorous silicon was all the rage when in1990 it was discovered to emit light.But dreams of incorporating it into mi-crochips were dashed by its fragility, be-cause the material could not withstandthe ordinary rigors of chip manufacture.In last November’s Nature, researchersat the University of Rochester and theRochester Institute of Technology re-port that they managed to fortify po-rous silicon with a double layer of sili-con oxide. The team then combinedthis so-called silicon-rich silicon oxidewith a conventional microchip, makingfor the first time an all-silicon systemthat in principle can process both lightand electricity.

IN BRIEF

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and other birds are claimed by some to have thrived with dinosaurs 140 million years ago.

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It is hard to see under the sea—par-ticularly if you are 120 metersdown, lying beneath a thick cover-

ing of ice during the endless nights ofthe Antarctic winter. Yet even in thisdeep night, hoards of tiny algae live in-side sponges, soaking up carbon diox-ide and, in turn, producing nutrients fortheir hosts. The mystery has been wherethese minute green plants get the lightthey need to drive photosynthesis.

Taking inspiration from the age oftelecommunications, Italian scientists re-cently discovered the secret of the sym-bionts. It turns out that some spongeshave a system of fiber optics that allows

them to gather what little light reachestheir murky depths and to direct it tothe algae. “We don’t give sponges muchcredit. Most people look at them andsay ‘this is a blobby lump,’” commentsMary K. Harper of the Scripps Institu-tion of Oceanography. “But consider-ing how primitive these animals are, it’samazing how adaptable they are.”

Like many sponges, the Antarcticsponge that the team from the universi-ties of Genoa and Perugia examined,Rossella racovitzae, has a skeleton com-posed of little silica spikes called spicules.They support the creature and keep pred-ators away. In the case of R. racovitzae,however, each spicule is capped with across-shaped antenna of sorts. The flat


In Brief, continued from page 18

Scanning for TroubleDiagnosing appendicitis has alwaysbeen dicey: one in five patients under-goes costly surgery without cause; an-other 20 percent go home only to getsicker. But a new CT x-ray technique, un-veiled at a December meeting of the Ra-diological Society of North America,should change that. The focused appen-dix CT, or FACT scan, capitalizes on dyein the colon to view the appendix—in-fected or not—more clearly. And becauseFACT scans home in on the abdomen’slower right quadrant only, they cost halfas much as full abdominal scans.

Twirly BirdsThis high-speed photograph, taken bybiologist Bates Littlehales of the Univer-

sity of California at LosAngeles, reveals whyphalaropes spin on thewater’s surface: whenthe wading birds chasetheir tails, they churn upprey. Littlehales and hiscolleagues caught thekinetic feeding on filmby placing the smallshorebirds in a tank con-taining dye-stained

brine. When the birds performed theirpirouettes, a tornado of fluorescentfood funneled up below them.

Protection with EstrogenNeuroscientists have uncovered sundryways in which estrogen protects wom-en from brain damage. Patricia Hurnand her colleagues at Johns HopkinsUniversity found that compared withmale rats, natural estrogen levels leavefemales three times less vulnerable tobrain damage from stroke. And SanjayAsthana of the Veterans Medical Centerin Tacoma, Wash., has demonstrated thehormone’s redemptive potential in Alz-heimer’s patients: in a small study of el-derly women with moderate dementia,estrogen patches temporarily improvedboth their attention and memory.

Antimatter in the MakingConfirming earlier results from CERN,physicists at Fermilab found seven anti-hydrogen atoms last November. Tomake the antiatoms—which contain anantiproton and a positron each—theteam sent an antiproton beam througha gas jet, thereby pairing electrons andpositrons and, in rarer instances, posi-trons and antiprotons.

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eight. Such a hemispherectomy is al-most a routine operation for some rareneurological conditions; in Alex’s case,it was Sturge-Weber syndrome, whichproduced a relentless succession of seiz-ures. The epileptic activity interfered somuch with the normal operation of hisbrain that he failed to develop languageskills in any form, apart from one or tworegularly used words and sounds.

For the first few months after theneurosurgical operation, Alex was kepton anticonvulsive medication. Then, amonth after his medication was with-drawn, he suddenly started uttering syl-lables and single words. His mother re-corded in her diary more than 50 words,primarily nouns but also verbs, adjec-tives and prepositions. Several months

later he had progressed to full sentences.According to the researchers, if there

is a critical period, Alex has raised its up-per limit to nine, a result consistent withat least one theory that suggests that thehormonal changes of puberty put a stopto the flexibility of the brain’s languageareas. The next step in studying this re-markable boy is to see if reading andwriting can also be learned without a lefthemisphere, at least up to a level thatwill enable him to navigate through theeveryday world of signs, forms and ce-real boxes. But even before that hap-pens, the Brain report is likely to provokea closer look and possibly a reworkingof the critical period hypothesis fore-shadowed in a forest in southern France200 years ago. —Karl Sabbagh

SOAKING UP THE RAYS

A sponge uses optical fibers to gather sunlight

MARINE BIOLOGY

CROSS-SHAPED SPOKESgrab light for an Antarctic sponge

known as Rossella racovitzae.

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Shining with the energy of a tril-lion suns, quasars are the bright-est as well as some of the most

distant objects in the known universe.Astronomers have devised theories toexplain what drives such infernos, butbecause they are so far away, gatheringthe evidence has been a challenge. Thedrought of data is coming to an end,however. Recent surveys conductedwith the Hubble Space Telescope haveanswered some key questions aboutquasars, although the surveys have alsohighlighted some gaps in the standardaccount. Meanwhile a study that com-bined the observing power of radio tele-

scopes in different countries has foundseparate evidence that all quasars oper-ate in fundamentally the same way.

Despite their prodigious luminosity,quasars are not large; they may be evensmaller than the solar system. The dom-inant view is that only a supermassiveblack hole—a body so dense that noteven light escapes it—can generate somuch energy in such a small space. Phys-icists calculate that if something pro-pelled a gas cloud into the vicinity of ablack hole, the gas could fuel a quasar.The black hole’s gravity would acceler-ate the gas to near the speed of light,turning it into plasma. Before being con-sumed, the fuel would be swept into amaelstrom called an accretion disk,where friction would efficiently gener-ate light and other radiation.

The new pictures by Hubble bolsterthat theory. The telescope has providedthe first clear view of the immediate en-


Semiconductors Get BentEager to show that crystal semiconduc-tors could be made flexible, researchersat the State University of New York atBuffalo deposited thin layers of semi-conducting materials onto weather-stripping silicone. The resulting semi-conductor, when peeled from the sili-cone, retained most of its properties.According to head researcher HongLuo, the semiconductor was tougherthan those crafted from bendable poly-mers and possessed better opticalproperties. They might prove useful inoptical circuits and in solar cells.

Rivals of the FittestIt may not be how far you run but howfast that counts. In a recent study ofmore than 8,000 athletes, researchers at

Lawrence Berkeley Na-tional Laboratoryfound that the fleetestof foot had the health-iest of hearts: slower,regular runners hadmore high-densitylipoproteins (“good”cholesterol) than

sprinters, but they also had higherblood pressure.

FOLLOW-UPProstate Cancer Gene IdentifiedCollaborators from Johns Hopkins Uni-versity, the National Center for HumanGenome Research and Umeå Universityin Sweden have found a stretch of chro-mosome 1 that can predispose men toprostate cancer. Indeed, mutations in agene in this region, named HPC1 forhereditary prostate cancer 1, probablyaccount for some 30 to 40 percent of allinherited forms of the disease. Some 5 to10 percent of all prostate cancers are ge-netic. (See September 1996, page 114.)

Losing on FusionA new take on how turbulence affectshot ionized gas in a tokamak may dashall hopes for the first controlled, self-sus-taining fusion burn. For a decade, scien-tists behind the International Thermo-nuclear Experimental Reactor (ITER)—a$10-billion multinational project—haveargued that ITER would demonstrate fu-sion’s practicality by 2010. But two phy-sicists at the University of Texas at Aus-tin suggest technical problems willmake the wait much longer. (See April1992, page 102.) —Kristin Leutwyler

In Brief, continued from page 24

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spokes of the antenna capture light,which then travels directly down the sil-ica tube of the spicule to the garden ofgreen thriving at the base. (Harper sus-pects that this mechanism might allowlarger numbers of algae to thrive be-cause there is more surface area in theinternal folds of the sponge than on itsouter surface.)

The researchers discovered R. racovit-zae’s system after firing red laser lightdown a straight, 10-centimeter-long spic-ule and observing its unimpeded travel.They then bent the spicule at various an-gles to see if it still successfully guidedthe red light—and it did. Although theyhave tested just the one sponge—largelybecause its spicules are long and easy towork with—the scientists think others

may use the same device. Group leaderRiccardo Cattaneo-Vietti says they willsoon begin looking at cave-dwellingsponges for the same adaptation.

Sponges are not the only owners of anatural light-guidance system. Accord-ing to Jay M. Enoch of the Universityof California at Berkeley, some cope-pods—another form of marine organ-ism—have light guides. And certain trop-ical plants have dome-shaped lenses ontheir leaves, allowing them to collect andfocus any light filtering down throughthe thick rain-forest canopy. As ThomasVogelmann of the University of Wyo-ming described a few years ago, theseleaf lenses lead to cells inside the plant,which, in turn, guide light to needy cellsat the base. —Marguerite Holloway

GALACTIC GUSHERS

Evidence mounts that black holes drive all quasars

ASTRONOMY

QUASARS IMAGED BY HUBBLEoccur in undisturbed galaxies (left) and in galaxies in the process of colliding (right).

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In Brief