In the textbook, we set out the current understanding of developmental processes and also provide some examples of “how we know what we know” in experimental boxes.  It is impossible however to present the raw data that provides the evidence on which our knowledge is based. The purpose of the practicals is to give you the opportunity of examining raw data and thus appreciate the way in which results are interpreted and lead to advances in understanding. The practicals involve analysing the results of experiments on chick wing buds (see Chapter 10), the morphology of stickleback fish collected from different habitats (see Chapter 14) and the mouse vertebral column (see Chapter 14). Ideally you would want to carry out the experiments and observe the specimens directly yourselves but the necessary facilities may not be available. It is also worth noting that the manipulations of the developing chick embryos are quite difficult and therefore these experiments are unlikely to generate results without some practice!  Therefore, you are provided with data to analyse and interpret obtained by Cheryll Tickle and members of her laboratory and presented in silico.  For both practicals, there is a list of tasks and questions under the heading 'Exercise' to guide your analysis and interpretation of the data. 

Teacher’s notes on answering the questions in the practicals are available in the lecturer resources on this site.