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:

Explain how plants absorb energy from sunlight
Describe short and long wavelengths of light
Describe how and where photosynthesis takes place within a plant

In the following video, Paul Andersen explains how energy can neither be created nor destroyed but may be transferred. Energy comes in many forms. [4:09]

Video tutorial breaks down photosynthesis into two stages: light dependent reactions and the Calvin cycle. [4:47]

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.

Students learn a simple technique for quantifying the amount of photosynthesis that occurs in a given period of time, using a common water plant (Elodea). They can use this technique to compare the amounts of photosynthesis that occur under conditions of low and high light levels. Before they begin the experiment, however, students must come up with a well-worded hypothesis to be tested. After running the experiment, students pool their data to get a large sample size, determine the measures of central tendency of the class data, and then graph and interpret the results.

Video lecture focuses on light-dependent reactions and how they work. It shows how light energy can excite electrons which can be used to create ATP and NADPH. [9:04]

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.

Through a teacher-led discussion, students realize that the food energy plants obtain comes from sunlight via the plant process of photosynthesis. They learn what photosynthesis is, at an age-appropriate level of detail and vocabulary, and then begin to question how we know that photosynthesis occurs, if we can't see it happening. Elodea is a common water plant that students can use to directly observe evidence of photosynthesis. When Elodea is placed in a glass beaker near a good light source, bubbles of oxygen will be released as products of photosynthesis. By counting the number of bubbles that rise to the surface in a five-minute period, students can compare the photosynthetic activity of Elodea in the presence of high and low light levels.

From radio waves to gamma rays, this video segment from NASA introduces the seven categories of the electromagnetic spectrum and how each type of radiation is part of our everyday lives. [2:58]

Students are introduced to sound energy concepts and how engineers use sound energy. Through hands-on activities and demonstrations, students examine how we know sound exists by listening to and seeing sound waves. They learn to describe sound in terms of its pitch, volume and frequency. They explore how sound waves move through liquids, solids and gases. They also identify the different pitches and frequencies, and create high- and low-pitch sound waves.

Discover how electricity can be converted into other forms of energy such as light and heat. Connect resistors and holiday light bulbs to simple circuits and monitor the temperature over time. Investigate the differences in temperature between the circuit with the resistor and the circuit using the bulb.

Students learn how the sun can be used for energy. They learn about passive solar heating, lighting and cooking, and active solar engineering technologies (such as photovoltaic arrays and concentrating mirrors) that generate electricity. Students investigate the thermal energy storage capacities of test materials. They learn about radiation and convection as they build a model solar water heater and determine how much it can heat water in a given amount of time. In another activity, students build and compare the performance of four solar cooker designs. In an associated literacy activity, students investigate how people live "off the grid" using solar power.

Sara and Finn are finding out how light travels. Join them, and learn the nature of light energy.

Students are introduced to the physical concept of the colors of rainbows as light energy in the form of waves with distinct wavelengths, but in a different manner than traditional kaleidoscopes. Looking at different quantum dot solutions, they make observations and measurements, and graph their data. They come to understand how nanoparticles interact with absorbing photons to produce colors. They learn the dependence of particle size and color wavelength and learn about real-world applications for using these colorful liquids.

Working as if they were engineers, students design and construct model solar sails made of aluminum foil to move cardboard tube satellites through “space” on a string. Working in teams, they follow the engineering design thinking steps—empathize, define, ideate, prototype, test, redesign—to design and test small-scale solar sails for satellites and space probes. During the process, learn about Newton’s laws of motion and the transfer of energy from wave energy to mechanical energy. A student activity worksheet is provided.

Student groups rotate through four stations to examine light energy behavior: refraction, magnification, prisms and polarization. They see how a beam of light is refracted (bent) through various transparent mediums. While learning how a magnifying glass works, students see how the orientation of an image changes with the distance of the lens from its focal point. They also discover how a prism works by refracting light and making rainbows. And, students investigate the polar nature of light using sunglasses and polarized light film.

Student teams conduct an experiment that uses gold nanoparticles as sensors of chemical agents to determine which of four sports drinks has the most electrolytes. In this way, students are introduced to gold nanoparticles and their influence on particle or cluster size and fluorescence. They also learn about surface plasmon resonance phenomena and how it applies to gold nanoparticle technologies, which touches on the basics of the electromagnetic radiation spectrum, electrolyte chemistry and nanoscience. Using some basic chemistry and physics principles, students develop a conceptual understanding of how gold nanoparticles function. They also learn of important practical applications in biosensing.

With an introduction to the ideas of energy, students discuss specific types of energy and the practical sources of energy. Hands-on activities help them identify types of energy in their surroundings and enhance their understanding of energy.