The main method of programme delivery is lectures, supplemented by practical classes and workshops. Lectures represent the largest proportion of the allocated contact hours, and allow the effective delivery of large amounts of knowledge, which forms the factual basis of a science subject. At level 1 the emphasis is on core knowledge across the broad spectrum of the sub-disciplines of biology. At levels 2 and 3, there are more specialised modules enabling students to focus on a particular sub-discipline, with elements of choice in the programme. There is an increasing emphasis as the lecture programme progresses on showing that biology is based on experimental evidence gained through research, so that at level 3 lecturing is research-led by being based on staff research interests. The proportion of the programme delivered through lectures is less at level 3 than in preceding years, to allow a greater emphasis on students' own research activities.