Historians of science generally consider that Darwinism has played an important part in the birth of scientific ecology. Now most 19th century seminal works of the new discipline have been elaborated within a Lamarckian framework. The source of this paradox lies in the double-content of the adaptation concept, considered as a static phenomenon by the ecologists and as a dynamic process by the evolutionists. Although closely related nowadays, as shown by modern evolutionary ecology, the problematics of the fields of research (...) at issue were initially separated. (shrink)