Although there have been ‘ecological’ ideas and investigations over many centuries, the history of ecology as a self-conscious science started only in the last decades of the nineteenth century. Originating from different roots, especially natural history and physiology, it soon developed into different specialities, such as animal and plant ecology, which at first developed at least partly independently from each other. Nevertheless, already from the first half of the twentieth century on, there have been attempts to arrive at unifying theories, an important culmination of which can be seen in the rise of ecosystems ecology. In the wake of an emerging awareness for environmental problems in the 1960s, ecology also became perceived by a broader public. This led to increasing demands on the science and also changed the work and subjects of ecologists to include much more application-driven and interdisciplinary research.

Key Concepts:

• Ecology has always been a hybrid science, building both on natural history and on physiology.
  
• The different traditions of ecology have developed partly independently during the first decades of ecology as a ‘self-conscious ecology’.
  
• Only since the 1960s and 1970s ecology became a field also known and valued outside smaller academic circles.
  
• Ecology is basically a biological science, must not be confused with ‘environmental thinking’.