There is no general PhD-program in biology at Stockholm University. Instead the different research departments at the Biology section of the Science faculty organize their specific, subject related programs. Thus, new PhD-positions are either announced by the respective departments, see links at research departments below and may also appear at the central announcement board at Stockholm University homepage.
Students apply to one of the specific PhD-position announced and it is then the different departments that decides who will be offered the position. This is the only way to be accepted on the PhD-program. However, even though there might not be an available position relevant for the research subject of your interest at the time you look, it is always a good idea to check out directly with principal investigators at the corresponding departments. There might be new PhD-positions soon to be announced.
The Biology section at Stockholm University Science faculty consists of three departments that are responsible for teaching and research at different areas of the biology subject. These are listed below with links to different departmental homepages. Please note that the Department of Biology Education, which also belongs to the Biology section, solely deals with education at undergraduate level; this department does not organize Ph.D-education.
Biology Departments: