This thesis covers the theoretical principles of outdoor teaching and discusses the question to which extent outdoor lessons have an impact on the learning process. Particularly when it comes to biology as a subject in school, outdoor lessons should be common practice. The direct encounter with plants or animals contains multi-sensory impressions and experiences which could not be achieved in conventional lessons. The resulting primary experiences of outdoor lessons lead to an intensification of learning processes and to a better relation between students and nature which is required for an eco-sensitive attitude. From a neurobiological point of view, particularly in times of smartphones and co., these experiences are highly valuable for children and teenagers. Besides cognitive and emotional aspects of learning, outdoor lessons also enhance social-communicative and instrumental competences. Therefore, since action-oriented, autonomous and social forms of learning are part of outdoor lessons, it comprises more than just the communication of knowledge. Interactions between the student and nature which are positively experienced by the student a vital element of outdoor lessons is the basis for acquiring subject-specific knowledge as well as for developing environmental-related action competence. In order to outline to which extent it is necessary to introduce more outdoor lessons, a survey was carried out within the framework of this thesis. The survey consisted of questionnaires which students of two schools in Graz were given and had to fill in in class. The big majority of them said they were prepared for practically dealing with wild plants. One third of the students reported a weak relationship to nature. As an example for contemporary and proper biology lessons, this thesis provides several wild plants.