This book synthesizes a wealth of international research on the critical topic of 'fostering understanding of complex systems in biology education'. Complex systems are prevalent in many scientific fields, and at all scales, from the micro scale of a single cell or molecule to complex systems at the macro scale such as ecosystems. Understanding the complexity of natural systems can be extremely challenging, though crucial for an adequate understanding of what they are and how they work. The term "systems thinking" has become synonymous with developing a coherent understanding of complex biological processes and phenomena. For researchers and educators alike, understanding how students' systems thinking develops is an essential prerequisite to develop and maintain pedagogical scaffolding that facilitates students' ability to fully understand the system's complexity. To that end, this book provides researchers and teachers with key insights from the current research community onhow to support learners systems thinking in secondary and higher education. Each chapter in the book elaborates on different theoretical and methodological frameworks pertaining to complexity in biology education and a variety of biological topics are included from genetics, photosynthesis, and the carbon cycle to ecology and climate change. Specific attention is paid to design elements of computer-based learning environments to understand complexity in biology education.