Big Idea: Diversity of Life is an expository nonfiction text organized in three chapters covering biodiversity (such as ecosystems and living and non-living things), grouping species (such as single-celled and multi-celled organisms and classifying plants), and humans and biodiversity (such as invasive species and protecting biodiversity). Each two-page spread is linked to a big idea, such as “Species that are not native to an area can harm biodiversity in the area.” Each chapter concludes with two activities written in procedural language, and a final activity challenges students to “think like a historian.”