This text has been written to match the content demands of the 1996 GCSE science separate subject syallbus documents. This work aims to provide an evolutionary perspective on modern biological thinking. It traces the development of living organisms from the prebiotic soup to complete cells and organisms. The book concludes with two studies which show the ways modern biologists apply their knowledge and understanding of living systems. The book contains: learning objectives for each chapter, to help aid private study; key point summaries, to emphasize ideas and aid revision; and examination-style questions to help students prepare for the GCSE examination.