In the 19th century, the parallel emergence of ecological science and ecological thought marked a break from the theo-ecology of the 18th century. In the 20th century, the new discipline produced concepts such as the ecosystem, the biosphere, or climax communities that contributed to the development of the systematic approach that currently characterizes ecological science as well as the ecologist project. More recently, the emergence of ecology in politics occurred in an entirely new economic, political, and social context. JEL codes: Q57, Q56