This no-prep unit on the evolution of zoos over time was designed to integrate reading, writing, and higher-order critical thinking with science content. Using the thinking tools of Depth and Complexity, scaffolded questioning, and visible thinking strategies, students will read and respond to content in rigorous and authentic contexts, and will be able to connect and apply their understandings in new ways. This unit is comprised of three Central Concepts which each build upon the previous. Each