de Beer • The Darwin-Wallace Centenary 



111 



Sir Gavin de Beer 



The Darwin-Wallace Centenary 



Reprinted by permission from Endeavour 17: 

 (66), April 1958. 



FROM SPECIAL CREATION TO 

 TRANSFORMISM 



Only one hundred years have gone 

 by since the concept of evolution was 

 brought to the attention of thinking 

 men in a manner which has compelled 

 its acceptance. The demonstration that 

 the members of the plant and animal 

 kingdoms are as they are because they 

 have become what they are, and that 

 change, not immutability, is the rule of 

 living things, is one of the most impor- 

 tant contributions ever made to knowl- 

 edge, and its effects have been felt in 

 every field of human thought. Some 

 naturalists, including Linnaeus himself 

 in his later years, adopted a compro- 

 mise, allowing that species could have 

 descended with modification from 

 genera, but that genera were immu- 

 table. 



THE FACT OF EVOLUTION 



When Darwin started on the voy- 

 age of the Beagle in 1831, he had no 

 reason to doubt the immutability of 

 species. The speculations of his grand- 

 father Erasmus counted for nothing 



with him, because they were not sup- 

 ported bv evidence. Those of Lamarck 

 on the causes of evolution had the ad- 

 ditional demerit of bringing the sub- 

 ject into disrepute by their fanciful 

 nature. It must be added that in Lyell's 

 "Principles of Geology," to which Dar- 

 win owed so much because of the gen- 

 eral background of uniformitarianism 

 in place of catastrophism that it advo- 

 cated, the possibility of evolution was 

 firmly rejected. 



Three sets of observations started 

 Darwin's revolt against the immutabil- 

 ity of species. The first was occasioned 

 by his studies of the fauna of the 

 Galapagos Islands, where he found 

 that species of finches differed slightly 

 from island to island, while showing 

 general resemblances not onlv to each 

 other but to the finches on the adja- 

 cent mainland of South America. If 

 these species had been separately cre- 

 ated, why should there have been such 

 a prodigal expenditure of "creations" 

 to resemble each other so closely; why, 

 in spite of the similarity in ph\'sical 

 conditions between the islands of the 

 Galapagos Archipelago and the Cape 

 Verde Islands, are there faunas totally 



