"There is grandeur in this view of life, with its several powers, having been originally breathed into a few forms or into one; and that, whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved." - from Charles Darwin's The Origin of Species
From a review. "Darwin's idea explains the production of differing species through natural selection. Darwin did little to explain evolution, or the change, of species, but this book fully outlines how the mechanism of selection would make sure such random changes would produce complex organisms. The mechanism Darwin proposes is at once so simple and seems so obvious with hindsight. It is something evident to any dog breeder--that traits can be selected and passed on to different generations--and Darwin even draws upon knowledge of artificial selection in birds and dogs to bolster his claims. Ultimately, however, the evidence for evolution by natural selection lies not in a vague analogy to artificial selection, but in the predictions Darwin's theory made and fulfilled. Darwin's expectation of biological similarity in ancestors and descendants is fulfilled by simply looking at exterior features or even bone structures. He also notes that his theory thoroughly predicts and explains the existence of rudimentary features like teeth in whale embryos and flightless wings in birds. The fact that island species correspond most with similar species on the nearest continent, instead of in distant lands, shows that these species are descended from them and changed after migrating to a separate environment. Darwin also showed how his theory explained the difficulties with classifying species, because evolution thoroughly broke down the distinction of species as pure and distinct."