Biogeographical Explanations

Abstract

The expansion into the whole world of European explorers had provided naturalists for the first time with a significant accumulation of biogeographical data. These data exhibited obviously significant regularities in the distribution of organisms, regularities that cried out for explanation. There was the relatedness of flora and fauna on islands and archipelagos. There was the gradual replacement of predominant life forms as one traverses a great continental land mass. There were the marked peculiarities of plant and animal populations cut off from other life forms by prominent surface features. There was the distinctive mountainous life zones which seemed a function of elevation.¹ Darwin himself had observed all these sorts of things carefully on the voyage of the Beagle. And in particular, of course, there was the experience of the Galapagos.²