Biology 2e is designed to cover the scope and sequence requirements of a typical two-semester biology course for science majors. The text provides comprehensive coverage of foundational research and core biology concepts through an evolutionary lens. Biology includes rich features that engage students in scientific inquiry, highlight careers in the biological sciences, and offer everyday applications. The book also includes various types of practice and homework questions that help students understand—and apply—key concepts. The 2nd edition has been revised to incorporate clearer, more current, and more dynamic explanations, while maintaining the same organization as the first edition. Art and illustrations have been substantially improved, and the textbook features additional assessments and related resources.

This pathway explores the importance of biodiversity and human impact on the environment.

Learn the difference between density-dependent and density-independent factors that affect population growth, and explore examples of each. [10:38]

Khan Academy learning modules include a Community space where users can ask questions and seek help from community members. Educators should consult with their Technology administrators to determine the use of Khan Academy learning modules in their classroom. Please review materials from external sites before sharing with students.

What effect do interactions between species have on the sizes of the populations involved? Learn about the dynamics of predator and prey populations, and how they can influence one another's patterns of growth and decline. [5:08]

Khan Academy learning modules include a Community space where users can ask questions and seek help from community members. Educators should consult with their Technology administrators to determine the use of Khan Academy learning modules in their classroom. Please review materials from external sites before sharing with students.

Ecosystems are organized into several different levels, and they can be studied at any one of the various levels of organization. Learn more about levels of ecological organization in this learning module produced by CK-12.

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In the following video, Evan Seimann, PhD, defines key terms and concepts of ecology, basic characteristics of populations, population age structures and densities, and explains the dynamics of growth models within a population. [22:59]

This activity is a simulation that illustrates how population sizes are affected by predator-prey relationships and competitive interactions among prey.