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The English naturalist, Alfred RusselWallace, is probably best known for hav-ing proposed a theory of evolut ion bynatural select ion independent ly ofCharles Darwin. He is probably less weliknown as the originator of the basic ten-ets of zoogeography. He descr ibed'Wal lace's Line' - - a zoogeographicalboundary running between Bal i andLombok that separates the fundamen-tal ly dist inct faunas of the Oriental andAustralasian biogeographical regions'These ideas occurred to him whi lstworking in this part of the world from1854 to 1862, a region which he referredto as the 'Malav Archipelago'but morerecognisable to modern readers as Indo-nesia. The f irst base for his work in theregion was Singapore.

Wallace was born on B )anuarY 1823at Usk, Monmouthshire in Wales. As a

1,outh, he became interested in botanyand began col lect ing plants. From 1839,he worked as t ra inee assistant to hisbrother Wil l iam, a land-surveyor. In1844, he met the naturalist Henry WalterBates while teaching at Leicester. Batesencouraged his interest in insects, par-t iculariy butterf l ies and beetles. Theirstudies and reading, part icular ly ofRobert Chambers' Vestiges of the Natu'ral Historv of Creot ion, convincedWaliace and Bates that species of plantsand animals evoived. Thus they wenton an expedit ion to the Amazon in 1B4B'in search of evidence that would con-vince scientists that evolution has in factoccurred. Wal lace remained in theAmazon Basin t i l l 1852 ar.rd col lectednearly 15,000 specimens. On his returnvoyage his ship caught fire and sank.His coi lect ions, apart from those mate-r ial already sent to Engiand, perished.The passengers and crew dri f ted in l i fe-boats for ten days, suffering from expo-sure, thirst and hunger. Most of the ma-terial with which Wallace had hoped tomake his case for evoiut ion were lost.

After four vears of work in the iun-gle. Wallace had very l i t t le to show otherthan his reputation as a col iector ' Thespecies problem he was interested in

Wallace in SingaporeLee Pheng Guan ond. Kong Nee

Department of Zoolog1t, National University of Singapore

was not solved. He had to set out oncemore to gather evidence. This time heruled out South America as a destina-tion because a good number of natural-ists such as Bates were already workingthere. From his detai led study of theinsect and bird specimens housed in theBrit ish Museum, he decided to recom- .mence his natural history coliections inthe Malay Archipelago with Singaporeas a starting point. At the time, the re-gion was general ly healthy and, exceptfor the Malay Peninsuia and Java, st i l lrelat ively unexplored. He applied to SirRoderick Murchinson, then President ofthe Royal Geographic Society, for helpin funding his expedition. Through thelatter 's efforts, Wallace was providedpassage on a P&O steamer, Euxine,bound for Alexandria. After a deiay ofseveral weeks because of the outbreakof the Crimean War, Waliace left Eng-land in Marcli 1E54,'bringing with himhis assistant, Charles Alien, the 16-year-old son of a carpenter. TheY disem-barked at Alexandria and crossed over-iand to Suez, *hence they boarded thesteamer Bengal for Singapore.

Wallace and Charles arrived in Sin-gapore on 20th Apri l 1854. In the f irstweek, he was busy arranging his fieldtr ips and accommodation. Eventual ly,he obtained permission to stay with aFrench Jesuit missionary i iving eightmiles out of town and close to the forestat Buki t Timah. The mission was sur-rounded by several wood-topped hi l ls,which were frequented by woodcuttersand sawyers. After sett i ing down withthe missionary, Wallace began his natu-rai history coi lect ions. He fol lowed aregular dai ly routine. On a typical day,he would Bet up at half-past f ive to takea bath and coffee. He would then sitdown to arrange and put awaY to drYinsects col lected the day before. Hisassistant would mend the nets; f i l l pin-cushions and prepare for the day's col-lecting. He wouid breakfast at eight, andat nine set out into the iungle. Theywould walk up the steep slopes of BukitTimah and arrive at the foiest drippingwith perspirat ion. Once at the top of

the hi l l , they would wander t i l l two orthree, general ly catching about 50 or 60beetles. Upon their return to the mis-sionary, Wai lace would bathe andchange clothes before sit t ing down toki l l and pin the insects. He would workon the beetles whilst Charles preparedthe f l ies, bugs and wasps. Thet 'wouldhave dinner at four, and then workedunti l six. After that there u,ould be cof-fee, reading, or i f the inser: t catch wasnumerous, more wotk preparing themunt i l e ig l - r t or n i t re o 'c lock, when thevwould ret i re to bed.

Wallace found the forest here vervsimilar to that of South America. Hedescribed Singapore as consist ing of amult i tude of smal l h i l ls , 90-120 m high.At the t ime, the summits of manv hi l lswere st i l l covered with primarv fbrest.There were always a few t igers ir t t i reforests, \ i l l ing on average a Chinese la-boure; { 'day. Wallace and his assistantheardithem roar once or twice in theevening, which made t\em rather n€rv-ous whilst hunting for irrsects. Tiger pitsweieh'bundant in the forest. These rirere4-6 m deep and covered with st icks andleaves. Wailace narrowlv escaped fromfalling into several of them. Sharp stakesused to be stuck at the bottom, but theiruse was banned af ter a t ravel ler hadbeen ki l led f rom lal l ing into a pi t . Thevegetation was luxuriatrt in the forestpatches Wallace and Charles worked in,with enormous trees. a varietv of ferns,caladiums and rattan. He noted nunter-ous palms and descr ibed them as 'gen-eral ly smal l and horr ib ly spinv' , t rn l ikethe large and majest ic s l tet ; ies of theAmazon. lnser; ts rarerer ext teedi t lg lvabundant and each dav's r ;o l lect ion fur-nished scores of new aud r--t t t ' ious torms.He was so busv col let ; t i r tg i r tsects i t r thethousands there was l i t t le t i rne for anv-thing clse. ' l ' l t t : [ reet le l r t t t t ra 'uvi ts par-t icular ly t ' i t ; l t . l t t abort t tw' t . r t r tot t ths heobtained no less than 700 species ofbee-t les, among which r t 'ere 130 dist inctk inds of Longicorns (Cerarnbvcidae).Almost al l of these were col lected in apatch of forest not more than 2.5 km' in

Cott. t on pag,e 6

. ' r - - .

[Con,t fron poge 5)

area. Wallace attr ibuted this produc-t iveness not onlv to the favourable con-dit ions lbund here but also to the la-bours of the Chinese woodcutters. Theyhad worked in the area for several yearsand had inadvertently provided a con-t inr,ral supplv ol food for beetle larvaein terms ol dead leaves, bark. wood andsawdust.

During the f irst six months Wallacespent in the region, Singapore was hisbase from which he made triPs to Ma-lacca and Sarawak, returning with hiscol lect ions to be arranged, examined,packed. insured and sent back to Eng-iand. Subsequently he moved east andwas to spend another seven-and-a-halfvears in the Indonesian Archipelago' Hemade 96 iournevs and visi ted almostevery group of is lands between theMalay Per-r insula and Atrstral ia, reach-ing as far east as the Aru Islands andNelv Guinea. Durlng these later travels,Wallace made Ternate in the Moluccashis base, returning to Singapore only toprepare for his return joltrnel ' to Eng-land. Al l in a1l, Wallace spent four pe-l iods in Singapore: 20 Apr i l - 23 lu ly1854, from his f irst arr ival in the east tohis tr ip to Maiacca; 2B September - 1"6October 1854 before going to Borneo; 31january - 24 Mav 1856 before venturingto the Indonesian Archipelago; and 20

|anuary - 20 February 1862 before set-t ing home for England.

Throughout his t ime in the MaiaYArchipelago, the quest ion of howchanges of species could have beenbrought about was rarelv out of h ismind. In Februarv 1855 in Sarawak, he\,\ i rote a prel iminary paper on evolut ionenti t led On the Lav'\Uhich Has Regu-lated the Introduction of New Species.It was an earlv exposit ion of evolut ionbut did not discuss i ts dynamics or themechanism ol natural select ion. Threevears later ir .r February 1BSB, Wallacei^,ras recovering from a severe attack ofmalaria at Gilolo (now Halrnahera) inthe Moluccas. He thought about humanevoiut ion and recal led the Essay onPopulat ion wr i t ten bi ' the economistThomas Malthus. He reported: 'Theresuddenlv f lashed uPon me the idea ofthe survival of the f i t test ' He draftedthe theory that evening and spent thetwo succeeding evenings writing out the12-page manuscript On the Tendenclt olVarieties to Depaft Indefinitelv from theOriginal !vpe. This was sent to Darwinby the next mail and reached him onl8th June 1858. The essav u'as tead.

together with an abstract of Darwin'sown views. as a lo int PaPer to theLinnaean Society on Lst July 1858. I treceived littie notice at the time and itwould not be unti l 1859, with the pub-Iication of Darwin's Origin oJ Species,that the theorv of evolution by naturalselection would have a signif icant im-pact on the scienti f ic world Mean-while, Wallace spent another four vearsin the Malay Archipeiago, far from thecentre of the scientific debate raging inEurope. ln the span of eight-years work,he travel led over 22,500 km, often bYsmall boat in pirate-infested waters. Hewas one of the most productive f ieldworkers of a l i t ime and col lected125,660 specimens, including B'050soecimens of b i rds, 7,500 shel ls, 13,100butterflies and 83,000 beetles. AlthoughWallace, with characterist ic humil i ty,described his discovery of the theory ofnatural select ion as an accidental f lashof insight, i t was a clear case of whatPeter Medawar would refer to as 'seren-

dipity favouring a prepared mind'. I twas his long-standing preoccupationwith the subiect of evoir-rt ion which ledhim to recognise natural select ion asan important principle of general appl i-cation.

On 20th January t8.62, Wallace leftSingapore for England. He was neverto return aithough he had hoped to doso. Besides his col lect ions, he took withhim two living ddult rnaie sp.ecimens ofLesser Birds of Paradise {Paradiseapapuana Bernstein) and a few loriesbought from a Chinese merchant in Sin-gapore. These birds were rareiy seenal ive in Europe and since they seemedhealthy. Wal lace was encouraged tobring them back. They. however. causedhim much trouble and anxiety. He hadto stav at Bombay lor a week to stock upon bananas to feed the birds. On boardthe steamer, he had to set traps for cock-roaches in the storerooms and hunt anhour every night to catch a few dozencif them. He had dif f iculty persuadingthe railway olTicials in Egypt to let himtransport the birds via rail from Suez toAlexandria. On board the ship in theMediterranean there were no cock-roaches with which to feed the birds sohe had to stop al Malta fbr a lor tn ightwhere an unl imited suPPIY of themcould be caught at a bakery. Eventually,despite cold winds on the Mediterra-hean and frost in France, the two birdsof paradise were brought safely to theLondon Zoo on 1st APri i 1862. TheYaroused a great deal of interest amonBthose who saw them. One l ived for a

year, the other two.

Wallace was a self '-taught, independ-ent thinker. He was enthusiastic about'far-out' ideas, and during his time' evo-lut ion was one such idea. I t was an hv-pothesis without a causal framework,hover ing precar iotrs lv betweet lpseudoscience and legi t i rnate science.Authors l ike ]ean Bapt is le Lamarck.Erasmus Dan^u' in and Chambers toyedwith the idea of evolut ion but none ofthem could suggest a workabie necha-nism to account for how biologicalchanges could have taken place. Quiteearly on, Wailace decided that an inten-sive investigation of the distr ibution ofplants and animals might just providethe answers, and i t was this bel ief thatstructured his rT'ork in the Amazon Ba-sin and Southeast Asia. In this sense,one mav sav that Wailace did not ob-serve ot col lect in a theoret ical vacuum.He had def in i te expectat ions as to whalhe would f ind, and part icular kinds ofinformation that he was looking for.When Darwin arr ived in the Galapagosin September 1835, he was st i l l acreationist. I t did not occur to him thati t would make much of a di f ferencewhich island a specimen came trom' orthat he would need more than a maleand q femple of each species. Thus backin Englar id. Darwin exper ienced greatdi f f icu{ty t ry ing to make do with a sant-ple that had not been pol lected with$isnew evoiut ionary hypodhesis in mlnd'\n Tl te 'Voyage of the Beagle, he're-marked that iust before he lef t theGalapagos, he real ised that the tortoisesoI each is iand seemed to be dist incl . buti t was too late to coi lect specimens tcri l lustrate his point. Wallace, with an opnorr hypothesis in tn ind, was sparedsuch dif f icult ies. This does not mean,however, that Wallace's scienti f ic meth-odology was hypothet ico-deduct ive.Al though manv of h is works containsuggesl ions lbr exper iments designed totest part icr.r lar hypotheses, he contr ib-uted l i t t le in th is wav. I l has been sug-gested that this may be due to lack ofopportuni ty or of formal t la in ing.Wallace's work originates in empir icismor inductivism. For everv sub)ect hetook up, he would f irst estabi ish theproblem. He would then thoroughlyreview the I i terature to ascertain rel-evant facts. Final ly, based on his owndiscoveries and on those of others, hewould construct a model to accounl forthe facts. This is an appropriate meth-odology for a historical science l ike thestudy of evolut ion, but u 'hat makesWallace's method noteworthv and pre-

i, tr ruftgs(Con,t from page 7)

vented him from veering off into emptyand wild speculation is his attention tofundamentals and his keen scienti f icscepticism, As John Locke put i t : ' . . . thenot entertaining any proposition withBreater assurance than the proofs it isbui l t upon wi l l warrant ' . WhenWaliace's conclusions were wrong, theyare more likely due to incomplete datarather than poor reasoning.

Wallace was especially innovative inconstructing models explaini.ng spatialpatterns and how these change overtime. His approach to the species prob-iem was through geography. ManY ofhis evolut ionary studies rel ied on ex-pl ici t iy spatial or regionai models. Hisdiscoveries in zoogeography lent sup-port to the fact of evolution. An exam-ple that comes to mind is the great dif-ference in faunal composit ion of theadiacent islands of Bal i and Lombok,illustrating that it is the history of mi-gration and not climate alone that de-termines the distr ibution of animals.Wallace's method of biogeographicalanalysis represents the birth of the mod-ern approach to the subiect. Historicalanalysis of biotas thus became a syn-thetic enterprise, relying on diversesources of information including biol-ogy, geoiogy and meteorology. Wallacehimself said that this synthetic methodwould transform the study of naturalhistory from 'an amusement', 'a trivialand aimless pursuit ' , and 'a useless ac-cumulating of barren facts' into 'a studywhich presents problems as vast, as in-tricate and as interesting as any whichthe human mind can be directed'.

The other maior theme of Wallace'sresearch programme was variation. Itwas Wallace's emphasis on studYinghuman and animal variation that helpedhim gain insight into the mechanism ofevolution - natural selection. Naturalselection acts upon variation, and likeDarwin, Wal lace was met iculous indocumenting variation in populationsof animals. Early naturaiists were al-ready aware that individuals of the samespecies exhibited variation but they con-sidered this variation more of a nuisancethan anything as it made organisms dif-ficult to classify. Following the preceptsof essentialism, they beiieved that theyneeded just one specimen to define aspecies which in their minds was un-changing and static. Variants were dis-carded as 'atypical ' . I t was the work ofscient ists l ike Darwin and Wal lacewhich pointed out the importance of the

study of variation. The backlash wasthat some natural ists then took i t tomean that every tiny difference iustifiesthe establ ishment of a new species.These, whom Ernst Mayr called 'speciesmongers', would describe every variantas a new species. This way of thinkingof species (the typological species con-cept) goes thoroughly against the grainof Darwin's and Wallace's work. ForWallace, variation was by no means asimple fact. He recognised six types ofvar iat ion: indiv idual var iat ion,polymorphism, local forms, mimicrY,races or subspecies, and true species'Modern systemat ists now fol lowWaliace's example in documenting vari-at ion; assiduously trying to get samplesthat represent the full range of local andgeographic variation; recording exactlywhere they had col lected their speci-mens and detailed notes about habitsand habitats. Only in this way can com-parative biologists decide whether avariant specimen belongs to a new spe-cies, a subspecies, or is iust part of therange of variation of a known species.Unfortunately for taxonomy, somepractitioners have yet to make such aparadigm-shift.

Although Darwin and Wallace werecodiscoverers'of ,the theory of natural se-lection, their position on the theory wasnot always the same. For one thing,Darwin always avoided assumptionsthat could notbe unequivoeally tested.Thus he eschewed arguments invokingfinal causes. In his opinion, evolution

. was a matter of history in the makingand natural selection was the main proc-ess through which new forms come intobeing. Wallace, on the other hand, be-lieved that evolution could not be putin context without finai causes operat-ing. He looked on evolution as a proc-ess that follows naturally from a fewuniversal physical and biological laws,and this eventually leads to the devel-opment of advanced beings and socialorganisation. This fundamentally deter-minist ic and teleological world viewapproximates, in many resPects, the'Gaia hypothesis' of |ames Lovelock. Itis the idea that the earth has evolvedsynergist ical ly, continual ly 'preparing'i tself for the production of more andmore complex beings. Such goal-di-rected explanations of natural processesare however, untenabie in science: first-

'ly, because we have no iustification forimputing purpose to natural phenom-ena; and secondly, these explanationscannot be used to formulate predictions.

Wallace was ahead of his t ime in hisadvocacy of conservation. Having seenthe destruct ion of t ropical forestsf irsthand, he was concerned about i tsIong-term effects. He wrote: 'the greaterpart of this waste and devastat ion hasbeen and is being carr ied on, not for anygood or worthy purpose, but in the in-terest ofpersonal greed and avarice'. Hemaintained that ' to pol lute a spring or ariver, to exterminate a [species ofl birdor beast, should be treated as moral of-fences and as social crimes'. Among themeasures that Wal lace advocated tocounter th is destruct ion was to estab-lish a system of strategically located for-est reserves where a representative sam-ple of the biota could be preserved andstudied by naturalists. If this soundsfamil iar although i t was writ ten arounda century ago, i t only serves to under-line the genius and foresight that wasWallace's.

Wallace died at the age of g0 inBroadstone, Dorset, on 7th November' lo l?

References,! i

Bern$tiin, R. (1982)New Scientist (3 june 1982): 652-Qp5.

Gebr6e, W. {1964) ' .Biologist Phi losopher: A Studv of theLife & Writings of Alfred RusselWallace. Abelard-Schuman. London.

Ghisel in, M.T. [1ss3)Paci [ ic Dist :overv (Spr ing 1993): 17-23.

Marchant, J, (1916)Alfred Russel Wallace: Letters &Reminiscences. Harper & Bros., N.Y.

McKinney, H.L. (1s72)Wal lace & Natural Select iou. YaleUniv. Press, New Havert.

Smith, C.H. (1991)Alfred Russel Wallace: An Anthologyof His Shorter Writ ings. Oxford Univ.Press, Oxford.

Wallace, A.R. (1869)The Malay Archipelago: The Land ofthe Orang-utan & the Bird of Paradise -A Narrative of Travel With Studies ofMan & Nature. MacMil lan Co.,London.

CHRONOLOGY OF WALLACE'S LIFE

B jan 1823

1837-7843

1.844-L845

Mar 1B4B- Jul 1852

6 Aug 1852

Mar 1854

Apr 1854- Feb 1862

Feb 1858

1 Jul 1B5B

1 Apr 1862

Apri l 1866

Feb 1869

1.870-1872.

LBS2

lul leoa I

Dec 1908

7 Nov 1913

Bom at Usk, Monmouthshire, Wales'

Apprenticed as surveyor to brother William insouthern England and Wales.

Employed as master at private school in Leicester:meets Henrv Walter Bates.

Collecting expeditions in Amazonia, South America'

Return trip to London; ship catches fire and sinkslWallace rescued at sea.

Leaves England for SingaPore.

Collecting expeditions throughout Indonesia'

Wrote On the Tendency of Varieties to Depart Indefi-nitely From the Original Type in Halmahera, theMoluccas.

Toint announcement of Darwin and Wallace of thetheory of natural selection at Linnaean Society'London.

Returns to London.

Marries Annie Mitten, daughter of botanist WilliamMitten.

Published The MalaY ArchiPelago'

President of the Entomological Society of London'

Awarded Founder's ybhlf from the Royal Geographi-a

cal SocietY 1 u,

Receives Darwin-Wallace Medal from fhe Linnaean'society of T.ondon. ;"

Awarded the Copley Medai from the Royal Societyand the Order of Merit from the crown'

Dies at Old Orchard, Broadstone, Dorset'

Singapore Institute of BiologYc/o Department of ZoologYNational UniversitY of SingaPoreKent Ridge. SingaPore 05 I I