Frozen Evolution. Or, that’s not the way it is, Mr. Darwin. A Farewell to Selfish Gene.

Preadaptations are biological structures or patterns of behaviour that developed in a different selection context than that in which they later became advantageous. A great many biological structures or patterns of behaviour were formed as a consequence of completely different selection pressures than would follow from their contemporary biological functions and, in some cases, the reason for the formation of the original structure was not selection at all. In this case, evolutionary biologists speak about the formation of the relevant structures on the basis of already existing preadaptation and the relevant traits are mostly not termed adaptation but rather exaptation. For example, The wings of insects apparently developed from structures that originally served the processes of respiration or, according to another theory, for thermoregulation, and thus they emerged and were formed over a long time through the action of selective pressures following from this original function.