Al­bert Wal­lace’s wildlife map was ground­break­ing

Bray People - - LIFE STYLE - JIM HUR­LEY

CHARLES DAR­WIN is gen­er­ally ac­knowl­edged as the per­son who first put for­ward what sub­se­quently proved to be an ac­cept­able sci­en­tific ex­pla­na­tion for the great va­ri­ety of life forms found on Earth. Dar­win made an out­stand­ing con­tri­bu­tion as a re­sult of his global trav­els, his many years of painstak­ing re­search and his deep think­ing.

Amaz­ingly, as Dar­win was per­fect­ing his ground­break­ing ideas about the ori­gin of species by nat­u­ral se­lec­tion Al­fred Rus­sell Wal­lace, an­other Bri­tish nat­u­ral­ist, was in­de­pen­dently ar­riv­ing at much the same con­clu­sions from a some­what dif­fer­ent per­spec­tive.

Since the six­teenth cen­tury sea­far­ers noted that dif­fer­ent an­i­mals were found in dif­fer­ent parts of the world. Ele­phants were found in Africa and Asia but not in South Amer­ica; Po­lar Bears oc­curred in the Arc­tic but not the Antarc­tic; pen­guins were quite the op­po­site. Kan­ga­roos were unique to Aus­tralia. Th­ese things were known and noted but not ex­plained.

Wal­lace trav­elled ex­ten­sively in the Ama­zon basin, south-east Asia and Aus­tralia and be­came the lead­ing author­ity of his time on the global distri­bu­tion of bio­di­ver­sity. He iden­ti­fied what be­came known af­ter him as ' the Wal­lace Line', a line through the East Indies that sep­a­rated two very dif­fer­ent as­sem­blages of an­i­mals. For ex­am­ple, the is­lands of Bali and Lom­bok lie a mere 35km apart yet they sup­port very dif­fer­ent types of birds.

Wal­lace in­de­pen­dently ar­rived at the con­cept of evo­lu­tion from his stud­ies and pub­lished a pa­per jointly with Dar­win in 1858. He first drew his now­fa­mous line in 1859 and pub­lished the first map of the bio­geo­graph­i­cal realms of the world in 1876. Since then his map has been the sub­ject of much study.

Twenty years ago an in­ter­na­tional team of sci­en­tists based at the Univer­sity of Copen­hagen in Den­mark set about re­vis­ing, amend­ing and up­dat­ing Wal­lace's map. More than 15 in­ter­na­tional re­searchers were in­volved and more than 20,000 species of mam­mals, birds and am­phib­ians were ex­am­ined in de­tail. And now, 136 years af­ter Wal­lace pro­duced the first map his work has been up­dated in­cor­po­rat­ing the lat­est tech­no­log­i­cal ad­vances in DNA-se­quenc­ing.

Pub­lished on­line in the jour­nal Sci­ence, the up­dated Wal­lace map may be ac­cessed on Google Earth via http://macroe­col­ogy.ku.dk/re­sources/wal­lace. The up­dated and amended ver­sion comes 136 years af­ter Wal­lace's orig­i­nal ver­sion. How­ever, ver­sion two is by no means de­fin­i­tive as the distri­bu­tion of plants and an­i­mals is cur­rently fac­ing sig­nif­i­cant change and blur­ring due to global warm­ing, cli­mate change and the world­wide spread of in­va­sive species.

Al­fred Rus­sell Wal­lace (1823-1913), orig­i­na­tor of a fa­mous wildlife map.

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