The implementation of the National Curriculum Statement in 2006 saw the name of the subject known as Biology change to Life Sciences accompanied by changes in subject content. The curriculum committee excluded systematics as a separate unit from the new outcomes-based Life Sciences curriculum for grades 10 to 12 that was implemented in 2006. Educators had to include aspects of systematics in teaching these concepts without guidance from the curriculum. This posed the question whether mastery of population dynamics and biodiversity is dependent on content of systematics in the context of the new curriculum. The New Content Framework for Life Sciences implemented in 2009 reintroduced systematics as a single unit. This raised the question why systematics has been reintroduced in the Life Sciences curriculum. This study aims to determine the influence the exclusion of systematics as a separate unit from the Life Sciences curriculum, implemented in 2006, had on the teaching of population studies and biodiversity. Data was gathered by evaluating and analysing the relevant curriculum statements, work schedules and content frameworks. Semi-structured interviews were conducted, first in 2008 when systematics was excluded from the curriculum and then in 2009 after the reintroduction. The first interviews dealt with the exclusion of systematics and the second interviews queried the reintroduction of systematics in the New Content Framework. Interviews were conducted with grade 11 Life Sciences educators at two secondary schools and two curriculum developers involved in compiling the Life Sciences curriculum. An expert in systematics and another in ecology were interviewed about the exclusion of systematics. The workbooks of some grade 11 learners were studied. Classroom observations were conducted when the relevant topics were being covered in class. A number of reasons for the exclusion of systematics from the NCS were advanced. These included: there was no population dynamics expert in the curriculum development team, emphasis was placed on outcomes and not content, the academic background of the members of the curriculum team and the difficulty of teaching systematics, perceived to be uninteresting. There was disagreement whether systematics is essential for understanding population dynamics but there is consensus that the study of systematics influences biodiversity and its exclusion left a regrettable void. However, systematics should be taught in a more interesting way. Prior knowledge is important for understanding of certain processes and concepts as well as for the application of practical skills like problem-solving and scientific inquiry. The curriculum does not provide detailed guidance on the content and practical activities to be covered and educators are encouraged to develop their own curriculum and activities. Experienced educators with strong academic backgrounds in animal and plant sciences referred to or used knowledge of systematics in some lessons. In 2009, systematics was reintroduced in the Life Sciences curriculum to ensure that learners understand biodiversity and evolution through natural selection. It provides learners a better foundation to understand similarities and differences in the structure and function of different organisms and body plans and ensures that they use higher-order thinking skills when doing problem-solving and scientific inquiry activities.