The German biologist Ernst Haeckel coined the term 'ecology' in 1866 to name the study of the relations between organisms and their environment. The field matured over the following decades, and in 1935 the British botanist Arthur Tansley introduced the concept of the 'ecosystem', framing organisms and their physical surroundings as a single system of interacting, interdependent parts. This gave ecology a unifying analytical idea and a basis for studying flows of energy and matter. The discipline subsequently informed conservation and environmental science.
It provided the scientific foundation for environmental thought and for ecological, landscape-led and resilience-based approaches to planning that treat the city as part of a wider living system.