Darwin and Natural Selection

Abstract

It is now my responsible and rather difficult task to tell in twenty minutes something of what the biological sciences and the world in general owe to Darwin, and more particularly of his brilliant work and deductions with reference to natural selection. To the man in the street, I suppose, Darwin was the nasty old man who said that we have all descended from monkeys. I need hardly say that this is a caricature of the situation. Charles Darwin would unanimously be acclaimed by biologists as the greatest naturalist of last century, and probably of all time. The zoologists and botanists of his day and of the centuries which preceded him were, for the most part, satisfied to observe and describe living organisms and give them a name. Darwin probably excelled them all in the powers of observation and exact description, but was not satisfied to stop there. He had a greater urge, and a greater capacity, than any of his contemporaries or predecessors to interpret nature - to answer the questions "Why!" and " Whence!" and "How have this and that living creature come to be as they are!" He thereby opened up much the most fascinating field of biological research. Before we can grasp the significance of natural selection, it is necessary to understand three sets of phenomena which were ever present in Darwin's mind, and were essential preliminaries to his main deductions, viz. the "web of life", the " struggle for existence ", and the occurrence of variation within the species.