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 population genetics and describe how scientists use population genetics in studying population evolution
Define the Hardy-Weinberg principle and discuss its importance

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

Describe the different types of variation in a population
Explain why only natural selection can act upon heritable variation
Describe genetic drift and the bottleneck effect
Explain how each evolutionary force can influence a population's allele frequencies

This explanation of genetic drift is straightforward and easy to understand. Illustrations are provided to help visual learners

Population genetics is the study of genetic variation in populations. This simulation allows the user to observe the frequencies of two alleles over time.

This site from the University of Arizona runs a two-step simulation of Genetic Drift. There are teacher's notes included. A great site to aid in understanding Genetic Drift.

This image of polydactyly illustrates one symptom of Ellis-van Creveld syndrome, which is commonly found in the Amish. Ellis-van Creveld is one example of the founder effect and genetic drift.

Discusses conditions needed for the Hardy-Weinberg Law to hold true and demonstrates calculations involving allelic frequencies to illustrate this principle.

A population is a group of organisms of the same species, all living in the same area and interacting with each other. Since they live together in one area, members of the same species reproduce together. Ecologists who study populations determine how healthy or stable the populations are. They also study how the individuals of a species interact with each other and how populations interact with the environment. Learn more about features of populations in this learning module produced by CK-12.

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

This site from Palomar College contains an interactive practice quiz containingfour questions on major concepts regarding gene flow. A great learning tool.

Discover what evolution is through a case study of a Hawaiian snail species' survival. [7:20]