Abstract
This thesis describes a research project that was carried out at the Centre for Science and Mathematics Education at Utrecht University between 1998 and 2002. The study addresses problems in learning and teaching genetics in upper secondary biology education. The aim of the study is to develop a theoretically founded
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and empirically tested learning and teaching strategy (LT strategy) to cope with these problems.
The study is designed according to the developmental research approach (Chapter 2). In developmental research educational researchers and teachers co-operate in defining and developing learning activities and testing these in classroom settings. The LT strategy will evolve in a process of cyclic empirical testing of scenarios (Chapter 4).
Literature review and focus group interviews with Dutch biology teachers (n=19) revealed that the main difficulties in genetics education are associated with its abstract and complex nature (Chapter 3). A separation of inheritance from reproduction and meiosis (resulting in abstract subject matter) and the occurrence of heredity phenomena at different levels of biological organisation (its complexity) account in considerable degree for learning problems.
More in-depth data about these key difficulties have been gathered, and design criteria defined, using theoretical and empirical sources (e.g. 12 students interviews, classroom observations, content analysis of textbooks, literature) (Chapter 3). The LT strategy has been developed, evaluated, revised and optimised in a cyclic process of testing scenarios in practice (case studies). Three case studies in different schools (n=3) and forms (n=5) were carried out and resulted in the yo-yo LT strategy for genetics . A formal description of the didactical structure of the final version of the yo-yo LT strategy for genetics is presented in chapter 5.
In the yo-yo strategy students are invited to think backward-and-forward between the levels of biological organisation and to interrelate the genetics concepts on these levels. Analogue to the toy yo-yo. In handling the yo-yo it is impossible to skip part of the descending or ascending pathway. It is possible to yo-yo upwards and downwards, but the anchor and starting point is always the same: the hand that handles the yo-yo. In the yo-yo LT strategy for genetics the starting and anchor point is the organismic level, from where the levels can be descended and ascended (yo-yo downwards) but also ascended to the population and community level and descended (yo-yo upwards).
The yo-yo strategy copes with the complexity by explicitly distinguishing the levels of biological organisation, and by descending and ascending these levels, starting from the concrete organismic level. Explicating the levels makes the transect nature of genetics transparent to students, and provides an insight into what hereditary phenomena, processes, and structures occur on the different levels of biological organisation. The genetics vocabulary is tuned to the specific level students are dealing with at that particular moment, which helps to prevent confusion. In this way, the educational difficulties with cytological concepts, chromosome structure, and the homologue chromosome concept that have been described in the literature are avoided to a great extent.
The yo-yo LT strategy emphasises the genetics key concepts per level of biological organisation and their interrelationships. The relationships between reproduction, meiosis, and inheritance on the organismic and cellular level is stressed, and at the same time these key concepts are made concrete. This diminishes the abstract nature of genetics. The problem posing structure of content-related partial questions and reflection activities provide students a motive to engage in the next learning activity, in which another, related key concept on a subsequent level of biological organisation is explored.
Because the levels of biological organisation play an important role in most biological topics, we have argued that the yo-yo LT strategy could be suitable for all biological topics transecting different levels of organisation, e.g. behaviour, evolution, and ecology.
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