Scilla's Treatise 1670Fig. – The famous frontispiece from Scilla’s treatise of 1670 defending the organic nature of fossils. The solid young man, representing the truth of sensory experi­ence, shows a fossil sea urchin in his right hand to a wraithlike figure represent­ing the former style of speculative thinking. With his left hand, the solid figure points to other fossils found in Sicily. The text proclaims: “Vain speculation un­deceived by the senses.” (from, Stephen Jay Gould, “The Structure Of Evolutionary Theory”, The Belknap Press of Harvard University Press”, Cambridge, Massachusetts, 2002).

Exaptation: 1. The use of a biological structure or function for a purpose other than that for which it initially evolved. 2. An evolutionary process in which a given adaptation is first naturally selected for, and subsequently used by the organism for something other than its original, intended purpose. 3. Exaptations – Features (such as feathers) that evolved by selection for one purpose (such as warmth) and were later adapted to a new purpose (such as flight). [more]. Exaptive: to show exaptation – featuring it.