An example of metaphor in popular science writing:
"…these changes in the properties of new generations combined with the struggle for existence and the survival of the fittest lead to the steady process of evolution of species, and are responsible for the fact that a simple mollusc, who was the king of nature a couple of billion years ago, has developed into a highly intelligent being like yourself…"
George Gamow (1961) One, Two, Three…Infinity. Facts and speculations of science, Revised Edition, Dover Publications, Inc., New York.
Note: explaining evolution in terms of the survival of the fittest can be seen as a tautology, as the fittest are defined in terms of evolutionary success, so the key feature here is differential survival and reproduction.
