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:

Define biodiversity in terms of species diversity and abundance
Describe biodiversity as the equilibrium of naturally fluctuating rates of extinction and speciation
Identify historical causes of high extinction rates in Earth’s history

Describes the meaning of biodiversity. Includes videos and review questions.

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Describes the causes of species diversity in an ecosystem, why it is important for an ecosystem to have stable biodiversity, what happens if it becomes unstable, and why biodiversity should be protected. Includes study and review questions, and links to additional resources.

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

This is a very good introduction to the role evolution plays in the development of biodiversity. These topics and extinction are explained with the use of colorful interactive pictures.

Learn about the diversity of species on Earth by exploring a cladogram, a graph-like tree of life that illustrates relatedness among species. Includes instructions for reading cladograms and a pie chart that summarizes the percentages of the world's living things that belong to select classifications.

Hear about what a species is and is not, and discuss ligers, tiglons, mule, hinnies, and dogs. [8:49]

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.

Understanding Biodiversity presents an overview of biodiversity, its importance and relevance to humans, all living things, and the Earth. It includes species pages and a template to engage and involve students in real-life data collection.

In this tutorial students can learn the definition of species, how new species evolve, and the processes that can cause new species to arise. At the end of the tutorial students can take a quiz to evaluate what they learned about speciation.