The Beak of the Finch by Jonathan Weiner is about two scientists who explore Charles Darwin's theory of evolution. The author reveals that Peter and Rosemary Grant, the scientists, believed Darwin did not fully understand the importance and relevance of his theory. The two scientists observed how natural selection applied to finches. They concluded that natural selection is continuous and always taking place.
Weiner provides an in-depth description of the processes that the two scientists went through to make their research successful. Furthermore, he interviews several biologists who focus on other animals. They collect information that Darwin did not, and they explain how the Grants motivated them to study more about evolutionary changes.
The author reveals the mystery and beauty in evolution and analyzes Judeo-Christian beliefs concerning evolution without bringing up the concept of God. He reveals interesting views about the pattern of evolution in different environments. The author also discusses the formation of species and implies that it does not occur because of geographical isolation. Furthermore, Weiner explains how hybrids are produced and the role they play in the formation of species.
Volcanic islands represent ideal laboratories for the study of ecology and living forms, for they permit flora and fauna to develop in almost complete isolation. From their origin as sterile masses of lava, over millennia they gradually develop topsoil; then seeds—borne by sea birds, by floating debris, or by humans on brief stops—begin to grow and develop. Once plant communities have been established, they form the basis for animal populations of marine mammals, pelagic birds, or insects and passerine birds blown off migratory courses by storms. A few small land vertebrates, depending on ocean currents, may arrive on floating rafts of vegetation. Once animal life has secured a foothold, it must cope with a climate, terrain, and ecology very different from those of its original habitat. In response, it adapts to the new conditions, over time developing into new and hitherto unknown species. Among the numerous volcanic islands of the world, the most famous are the Galápagos chain off the coast of Ecuador, which Charles Darwin visited in 1835 as a naturalist aboard HMS Beagle.
During his stops among the islands, Darwin collected specimens of flora and fauna for further study in England, as he had done in other locations on the voyage. The collected species included several finches of a kind he had never seen; all were similar in color but variable in size and behavior. Most striking to Darwin were the varying sizes of their beaks, suggesting different feeding patterns, though at first he saw little scientific significance in that fact. After returning to England, he posted their skins to the ornithologist John Gould in London and was surprised by his verdict that the finches belonged to previously unknown species. In time, the fourteen species of finches inhabiting the islands became the most studied group of birds in the world. Once it had been determined that they were all descended from a single species, numerous scientists have attempted to explain how this differentiation occurred. Since Darwin’s time, one of the native Galápagos species, the largest and the weakest flyer among them, has become extinct, but thirteen species remain on the islands.
Jonathan Weiner’s book is primarily an account of one such study of Galápagos finches. Despite its extensive scientific bibliography, it is not a scientific report but rather a narrative of the project of Peter and Rosemary Grant, who have led an ongoing study from Princeton University for the past twenty-one years. They have centered their study upon the ground-feeding finches indigenous to one small uninhabited island, Daphne Major, near the center of the Galápagos chain. While the ground feeders comprise six species, Daphne Major has only three or four species in any numbers....
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