Appendix Dissertation Christian Hörsch:
Understanding biology - microorganisms and microbial processes in humans

Microorganisms and their effects in the human body are essential aspects of the living environment of schoolchildren. Pathogens and the necessary protective measures play a particularly important role in maintaining health. Everyday experiences include the symptoms of illness when the body has been infected with flu, mumps or chickenpox pathogens, as well as vaccinations against tetanus, polio or other diseases. Unfortunately, nowadays young people are also confronted with the danger of terrorists using anthrax and smallpox pathogens specifically for their attacks in any possible location or that bacteriological weapons could be used in crisis areas.

The pupils are not aware of the significance of pathogens in many everyday phenomena. They learn certain rules of behaviour in relation to hygiene, personal hygiene, handling food or spatial conditions without being aware of the underlying biological relationships.

A comprehensive understanding of microorganisms and microbial processes in the human body also includes the interactions that take place without negative findings or are even beneficial to health. The skin, the oral and pharyngeal cavities, the respiratory tract and the gastrointestinal tract are areas of the body in which the presence of microorganisms is normal and does not lead to disease if the human host's defences are unimpaired. Through biology lessons, pupils should become aware of microorganisms as omnipresent companions of human life and learn to understand them in the whole range of their effects in the human body.

The didactic reconstruction of the topic "Microbes and microbial processes in humans" should lead to fruitful and sustainable learning in biology lessons by linking scientific and learner perspectives.

In the subject clarification, scientific theories, methods and terms are analysed with the intention of teaching using qualitative content analysis of selected sources. For this purpose, both historical texts (Fracastoro, Pettenkofer) and current sources (Madigan et al., Postgate) are used and their limitations, personal views, scientific and epistemological positions and the use of specialised terminology are examined.

Problem-centred, guideline-structured individual interviews are conducted to record student perspectives. The research question relates to the perceptions of microbes (and viruses) and microbial processes of pupils in lower and upper secondary schools. The pupils' ideas are not dismissed as misconceptions, but are treated first and foremost as a necessary starting point for learning. The interest in knowledge is directed towards the elaboration of individual thought structures and their generalisation. The aim is to identify area- and topic-specific ways of thinking.

In the didactic structuring, the results of the surveys of subject-specific conceptions and student conceptions are brought together and related to each other in a mutually contrasting comparison.

Bringing together the academic and learner perspectives helps to find guidelines and construct teaching elements. The didactic structuring thus leads to decisions on objectives, content and methods for teaching that can be generalised and do not depend on the situational conditions of individual teaching projects. The results of the planned study can be used fruitfully as principles for lesson planning not only in health education, but also in other subject areas of biology that deal with microorganisms.

Hörsch, C. (2004). How did the world come into being? Creationism and evolutionary theory in American schools. In: Gropengießer, Harald, Janßen-Bartels, Anne, Sander, Elke (eds.), Lehren fürs Leben. Didaktische Rekonstruktion in der Biologie, Aulis Verlag Deubner, 180-189.

Hörsch, C. (2005). SARS - Confronting the danger of an epidemic. Unterricht Biologie 29: 301, 21-30.