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 species and describe how scientists identify species as different
Describe genetic variables that lead to speciation
Identify prezygotic and postzygotic reproductive barriers
Explain allopatric and sympatric speciation
Describe adaptive radiation

Review the process of species changing and evolving over time.

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

Discusses how new species evolve.

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

In this out of class tutorial, students explore several examples of natural selection and speciation.

Learn how genetic variation is the raw material of evolution, and learn how restricted gene flow can lead to the formation of new species. [11:52]

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 animation features the anole lizards as an example of how a single species can split and multiply into many different species with distinct traits. [2:38]

Understand how species develop and change over time.

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

The creation of a new species is called speciation. Most new species develop naturally. But humans have also artificially created new breeds and species for thousands of years. Learn more about origin of species in this learning module produced by CK-12.

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

Learn about speciation, including allopatric and sympatric speciation and mechanisms of reproductive isolation. [10:46]

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 lesson discusses how and why plants and animals adapt to their surroundings over time. It is 3 of 4 in the series titled "Speciation and Natural Selection."

Video discusses the concept of evolution and the five processes that can cause it to happen. [5:24] Includes a brief quiz and a list of additional resources to explore.

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.

What is evolution? This thorough site provides the basics of evolution focusing on the history of life, processes of evolution, microevolution, macroevolution, and more.