Principles of Biology is reflective of the shift taking place in the majors biology course from large and detail rich to short and conceptual. A succinct and inviting text focused on central concepts, Principles of Biology helps students connect fundamental principles while challenging them to develop and hone critical thinking skills. Based on recommendations from the AAAS Vision and Change Report, content has been streamlined to assist students in connecting broad themes and key ideas across biology. Beginning in Chapter 1, twelve principles of biology are introduced and revisited throughout the text to help students understand stay focused on core ideas. New BioConnections features and Check Your Understanding questions ask students to be self-aware learners, analyzing what they're learning and making connections. To help students understand the key theme in biology - evolution - new Evolutionary Connections features reveal the ways in which the theory of evolution connects and informs our studies. New Quantitative Reasoning skills boxes encourage students to focus on developing reasoning and critical thinking skills.