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:

Compare innate and learned behavior
Discuss how movement and migration behaviors are a result of natural selection
Discuss the different ways members of a population communicate with each other
Give examples of how species use energy for mating displays and other courtship behaviors
Differentiate between various mating systems
Describe different ways that species learn

This pathway provides an introduction to cellular mechanisms of communication, highlighting one of the primary mechanisms: signal transduction pathways. For a deeper look at this topic, we recommend the pathway Cell Communication from the OpenStax textbook Biology for AP® Courses.

Superior site for information on cell signaling. Information provided as a tutorial with multiple choice questions to guide the learner. The site has lots of images and diagrams.

Students pass around and distort messages written on index cards to learn how we use signals from GPS occultations to study the atmosphere. The cards represent information sent from GPS satellites being distorted as they pass through different locations in the Earth's atmosphere and reach other satellites. Analyzing GPS occultations enables better global weather forecasting, storm tracking and climate change monitoring.

Filtering is the process of removing or separating the unwanted part of a mixture. In signal processing, filtering is specifically used to remove or extract part of a signal, and this can be accomplished using an analog circuit or a digital device (such as a computer). In this lesson, students learn the impact filtering can have on different types of signals, the concepts of frequency and spectrum, and the connections these topics have to real-world signals such as musical signals. Students also learn the roles that these concepts play in designing different types of filters. The lesson content prepares students for the associated activity in which they use an online demo and a variety of filters to identify the message in a distress signal heavily corrupted by noise.

Students learn the basic principles of filtering as well as how to apply digital filters to extract part of an audio signal by using an interactive online demo website. They apply this knowledge in order to isolate a voice recording from a heavily noise-contaminated sound wave. After completing the associated lesson, expect students to be able to attempt (and many successfully finish) this activity with minimal help from the instructor.

This animation from NOVA: "Battle in the War on Cancer: Breast Cancer" describes how oncogenes cause cancer and how cancerous cells can spread throughout the body.

Students learn about the remote sensing radio occultation technique and how engineers use it with GPS satellites to monitor and study the Earth's atmospheric activity. Students may be familiar with some everyday uses of GPS, but not as familiar with how GPS technology contributes to our ongoing need for great amounts of ever-changing global atmospheric data for accurate weather forecasting, storm tracking and climate change monitoring. GPS occultations are when GPS signals sent from one satellite to another are altered (delayed, refracted) by the atmosphere passed though, such that they can be analyzed to remotely learn about the planet's atmospheric conditions.

Students work as if they are electrical engineers to program a keyboard to play different audible tones depending on where a sensor is pressed. They construct the keyboard from a soft potentiometer, an Arduino capable board, and a small speaker. The soft potentiometer “keyboard” responds to the pressure of touch on its eight “keys” (C, D, E, F, G, A, B, C) and feeds an input signal to the Arduino-capable board. Each group programs a board to take the input and send an output signal to the speaker to produce a tone that is dependent on the input signal—that is, which “key” is pressed. After the keyboard is working, students play "Twinkle, Twinkle, Little Star" and (if time allows) modify the code so that different keys or a different number of notes can be played.

A screencast lesson introducing the appropriate use of transitional words and phrases that signal sequence. [2:29]

Echolocation is the ability to orient by transmitting sound and receiving echoes from objects in the environment. As a result of a Marco-Polo type activity and subsequent lesson, students learn basic concepts of echolocation. They use these concepts to understand how dolphins use echolocation to locate prey, escape predators, navigate their environment, such as avoiding gillnets set by commercial fishing vessels. Students will also learn that dolphin sounds are vibrations created by vocal organs, and that sound is a type of wave or signal that carries energy and information especially in the dolphin's case. Students will learn that a dolphin's sense of hearing is highly enhanced and better than that of human hearing. Students will also be introduced to the concept of by-catch Students will learn what happens to animals caught through by-catch and why.