a

. “... the discovery of the Danish scientist W. L. Johannsen that the more or less constant somatic variations upon which Darwin and Wallace had placed their emphasis in species change cannot be selectively pushed beyond a certain point, that such variability does not contain the secret of ‘indefinite departure.’ ” Loren Eiseley, Darwin’s Century (Garden City, New York: Doubleday & Co., Inc., 1958), p. 227.

b

. “The awesome morphological complexity of organisms such as vertebrates that have far fewer individuals on which selection can act therefore remains somewhat puzzling (for me at least), despite the geological time scales available ...” Peter R. Sheldon, “Complexity Still Running,” Nature, Vol. 350, 14 March 1991, p. 104.

c

. Bland J. Finlay, “Global Dispersal of Free-Living Microbial Eukaryote Species,” Science, Vol. 296, 10 May 2002, pp. 1061–1063.