Although the history of terms and concepts proves to be very productive in the terminology of some domains, here the domain of ecology, it is still only rarely mentionned in books and articles which deal with terminology. However, despite what one may still consider as a generally unfavourable climate, the history of concepts needs to be developped for at least two reasons. First, it shows that two concepts are not always strictly identical, even if they wear names which appear to be equivalent or translated from one language into another. This is the case for the terms écosystème and ecosystem. Second, concepts that translators may consider as well-known and easy to understand, sometimes appear to be more complex than what they seem to be. This is the case for the concepts COMMUNITY and COMMUNAUTÉ. A quick study of the history of the concepts ECOSYSTEM and ÉCOSYSTÈME, shows that translators and terminologists would higly benefit from a more regular use of the historical information gathered on concepts and terms.