Written primarily for 16-19 year old students, this primer introduces the key features of the marine environment and explores definitions of marine biodiversity at different levels of biological organization: genetic, species, ecosystem, and functional. It also discusses how changes in ocean features due to human activities are having a negative impact on marine biological diversity. The primer aims to extend students' knowledge and inspire them to take their school-level learning further. It explores topics that are familiar from the curriculum and also introduces new ideas, giving students a first taste of the study of biology beyond school-level and demonstrating how concepts frequently encountered at school are relevant to and applied in current research. This is an ideal text to support students who are considering making the transition from studying biology at school to university. Digital formats and resources The book is available for students and institutions to purchase in a variety of formats, and is supported by online resources: - The e-book offers a mobile experience and convenient access along with functionality tools, navigation features, and links that offer extra learning support: www.oxfordtextbooks.co.uk/ebooks - Online resources include multiple choice questions for students to check their understanding, and, for registered adopters, figures and tables from the book