The IBO theoretical tasks should test the competitors’ understanding, processing skills and application of biological knowledge. Questions should require understanding, rather than knowledge. Theoretical questions should cover the following topics in the indicated proportions; Cell biology (20 %), Plant anatomy and Physiology (15%) (with emphasis on seed plants), Animal anatomy and physiology (25 %) (with emphasis on vertebrates and especially man), Ethology (5 %), Genetics and Evolution (20 %), Ecology (10 %), Biosystematics (5 %). Though some of these subjects are included in most secondary school biology programs, for the most part, they are evaluated at a much deeper level and many may require a level of knowledge and understanding comparable to that of post-secondary education. In addition, the host country of each IBO issues a set of preparatory problems well in advance of the competition every year. These preparatory problems cover specific topics in considerable more depth than typical post-secondary education.
Kindly download the detailed syllabus of the International Biology Olympiad via this link http://www.ibo-info.org/pdf/IBO-Guide.pdf