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.

By the end of this section, you will be able to do the following:

Describe the unique anatomical and morphological features of flatworms, rotifers, and Nemertea
Identify an important extracoelomic cavity found in Nemertea
Explain the key features of Platyhelminthes and their importance as parasites

By the end of this section, you will be able to do the following:

Describe the unique anatomical and morphological features of molluscs and annelids
Describe the formation of the coelom
Identify an important extracoelomic cavity in molluscs
Describe the major body regions of Mollusca and how they vary in different molluscan classes
Discuss the advantages of true body segmentation
Describe the features of animals classified in phylum Annelida

Plate Tectonics provides geology with a comprehensive theory that explains how the Earth works.

As part of the General Chemistry Virtual Textbook, this site examines a variety of topics related to the Earth. This page looks at the Earth and its lithosphere, the chemical composition of the Earth, the structure of the Earth, and more.

See how scientists study mantle convection, or the flow of hot rock in the Earth's deep interior, in order to better understand how this flow shapes the surface of the Earth. Learn how convection makes the Earth dynamic. [7:10]

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.

This 12-minute video lesson looks at the structure of the earth. The discussion includes the crust, mantle, core, lithosphere, asthenosphere, mesosphere, outer core, and inner core. [Cosmology and Astronomy playlist: Lesson 50 of 85]

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.

This 10-minute video lesson covers the structure of the Earth: The crust, mantle, and core. [Cosmology and Astronomy playlist: Lesson 44 of 85]

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.

Identifies and describes the two internal layers of Earth.

A free CK-12 account is required to view all materials.

This comprehensive study guide covers the main terms and concepts needed for an earth science unit on the earth's interior. Review questions are included at the bottom of the study guide.

A free CK-12 account is required to view all materials.

Covers volcanic activity occurrence within oceanic and continental plates.

A free CK-12 account is required to view all materials.

Volcanoes most often occur at plate boundaries.

A free CK-12 account is required to view all materials.

Volcanoes most often occur at plate boundaries.

A free CK-12 account is required to view all materials.

Earth's interior is broadly grouped into three main layers on the basis of chemical composition: crust, mantle, and core. An egg analogy is used to show relative thicknesses, and a Big Hunk analogy illustrates how a material of a single composition can be either brittle or ductile depending on temperature. [6:20]

This animation discusses the history of the discovery of the Mohorovicic Discontinuity, as well as the logic behind it. Spoiler Alert: It is about Snell's Law. [9:22]

Windows only - Interact with the tectonic plates of the Earth and see how changing variables affects the plates.

Students gain an understanding of the layers of the Earth by designing and building clay models.

This is a website to learn not only about the inner and outer core, but also about the crust and the mantle of the interior of the earth.