On 27 May we got up at 3am, left Payangan at 4am, and flew from Bali to Sumbawa (Nusa Tenggara). In and of itself, not that amazing of a feat but in what should have been a 1 hour, 15 minute flight (with a short stopover in Lombok) we went from one side of the Wallace Line to the other.
For those who don't know, Alfred Russel Wallace was a contemporary of Charles Darwin. Fourteen years younger, he was, essentially, the reason Darwin finally let the world know about evolution by natural selection. And although we usually hear the theory credited to Charles Darwin, it was announced to the world by a joint paper between the two presented at the Royal Linnean Society on July 1, 1858. Darwin had the good luck of being born into an upper-class educated family and studied both medicine and theology before heading off at the age of 22 on his famous voyage with the crew of H.M.S. Beagle. They left England at the end of 1931 for a 5-year voyage that lead him, among other places, to the now famous Galapagos Islands where he collected a number of species, including all those related finches. He brought a copy of Charles Lyell's 1930 book (Principles of Geology) that made the case for uniformitarianism, the theory that geology was not a product of a series of modern catastrophic events but that slow, gradual processes were shaping the Earth. In 1930, this was, essentially, heretical since at this time, by counting back generations in the bible, it was uniformly accepted that Adam had been created 6,000 years ago and that was the age of the Earth. The theory of uniformitarianism made the case for a much, much older planet. So, let's hear it for the power of a book (no wonder Christian fundamentalists and their toddy politicians want to ban them in the U.S.), the ideas circulated in Darwin's mind and back in England, looking at the beaks of those birds, he realized that they must all have a single common ancestor and that through non-random selections of mates, they had evolved into the 14 very different birds whose skins he had in front of him. Darwin, student of theology and upstanding member of society, couldn't bring himself to let anyone but his closest friends know what he suspected because it was too revolutionary an idea to be comfortable.
Alfred Russel Wallace was born in Wales and dropped out of school at age 14. In 1848, he traveled with Henry Walter Bates (another of my naturalist heroes) to South America for a collection trip that lasted four years (A Naturalist on the River Amazon is a great book if anyone is looking for some summer reading!). He returned to England for a couple years and then left again in 1854 to travel in Southeast Asia on another collecting trip that lasted eight years. It was on this trip that he realized there were amazing differences in the flora and fauna of the islands of the eastern part of what is now the Indonesian archipelago compared to the western part. The line runs between Bali and Lombok and even through the two islands are very close to one another, the biology of Bali is closer to that of Kalimantan than Sumbawa/Lombok. No natural phenomena (soils, rainfall, etc.) could account for this and he realized that it had to be due to slow movement of land masses bringing islands together whose ancestors had originated from distant areas. He mapped the area and this line that separates the Oriental and Australian biological regions still pretty much holds today (there have been a few people who've moved it a little based on more recent discoveries, but Wallace's original is still widely used).
In 1858, while ill in Indonesia Wallace realized that these differences he was seeing had to be due to evolution of species. He wrote to Charles Darwin (who was, by now, a respected scientist) explaining his reasoning and asking if Darwin would pass his letters on to Lyell. By this point, Darwin had been sitting on his ideas of natural selection for nearly two decades and, by all accounts, was not too pleased with this self-educated unknown scooping him on his theory. He shared Wallace's letter and his concerns with Charles Lyell who, together with Joseph Hooker, decided that the only thing to do was to quickly make a joint publication on the theory. The original presentation was given without Wallace's approval or input and (most likely) due to the clever framing of the paper, Charles Darwin is the name that has gone down in history, with Wallace's important discoveries nearly forgotten. Yet, in reading Wallace's work, he held no ill-will against Darwin, Lyell or Hooker and dedicated his seminal (in my mind!) work, The Malay Archipelago, to Charles Darwin as a token of his esteem and "to express my deep admiration for his genius and his works." Class act.
Anyway, the realization of the importance of natural selection to evolution and the remarkable coincidences that brought these two men to the same conclusion within a few years of each other is something I've been lecturing on for ages and having the opportunity to be on both sides of the Wallace line, going from one to the other in a matter of hours, has long been a dream of mine. I'm so happy to have finally had the opportunity to have seen these changes.