Use of English PRO

Charles Darwin did not invent the concept (0) OF evolution. When he was a student in Edinburgh in the late 1820's, evolution was already the (1) ............ of the town. But evolution was rejected by the establishment. Those who (2) ............ to evolutionary thinking were called Lamarckists, after the French scientist Jean-Baptiste Lamarck, who was the first to propose that species are not static, but change over time and give (3) ............ to new species. Lamarck had offered this (4) ............ in a book published in 1809. He did not, however, propose a correct mechanism for (5) ............ species change into each other. The mechanism was discovered first by Charles Darwin and independently by Alfred Russel Wallace. From reading the economist Thomas Malthus, Darwin was aware of the consequences of (6) ............ growing populations. Once resources become limiting only a (7) ............ of individuals can survive. Darwin was also an (8) ............ observer of animal breeders. He analysed their methods and studied their results. Slowly he understood that nature like a gigantic breeder.