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:

List the characteristics of fungi
Describe the composition of the mycelium
Describe the mode of nutrition of fungi
Explain sexual and asexual reproduction in fungi

Two lessons and their associated activities explore cellular respiration and population growth in yeasts. Yeast cells are readily obtained and behave predictably, so they are very appropriate to use in middle school classrooms. In the first lesson, students are introduced to yeast respiration through its role in the production of bread and alcoholic beverages. A discussion of the effects of alcohol on the human body is used both as an attention-getting device, and as a means to convey important information at an impressionable age. In the associated activity, students set up a simple way to indirectly observe and quantify the amount of respiration occurring in yeast-molasses cultures. Based on questions that arise from this activity, in the second lesson students work in small groups as they design and execute their own experiments to determine how environmental factors affect yeast population growth.

Paul Nurse describes his research that showed that humans share some genes with organisms as different from us as simple brewer's yeast. Footage from Secret of Life: "Immortal Thread."

What is ethanol? How much corn is dedicated to ethanol production? Why should corn be used to produce ethanol?

In the U.S., fuel ethanol production primarily utilizes corn, converting its starch into simple sugars for fermentation by yeast, yielding ethanol and byproducts like animal feed and CO2. This process, centered on fermentation, transforms sugars into ethanol and carbon dioxide, with about half a pound of ethanol produced per pound of sugar. Corn's high carbohydrate content makes it an efficient feedstock, allowing for the production of around 2.8 gallons of ethanol per bushel. Ethanol production not only uses the starch but also generates distillers grain, enriching livestock feed with remaining nutrients. Notably, 40% of U.S. corn goes towards ethanol production, enhancing energy independence by reducing oil imports, with 14.3 billion gallons of ethanol in 2014 offsetting 512 million barrels of crude oil. Ethanol's production energy primarily derives from solar energy captured by corn, with its energy output exceeding the fossil fuels used for its cultivation and processing by 20-40%. Additionally, ethanol offers environmental benefits, including a 10-20% reduction in greenhouse gases compared to gasoline, equivalent to removing 20 million vehicles from the road, highlighting its role in sustainable energy and reduced greenhouse gas emissions.

This learning module includes 7 lessons and/or activities.

Students set up and run the experiments they designed in the Population Growth in Yeasts associated lesson, using simple yeast-molasses cultures in test tubes. Population growth is indicated by the amount of respiration occurring in the cultures, which in turn is indicated by the growth of carbon dioxide bubbles trapped within the culture tubes. Using this method, students test for a variety of environmental influences, such as temperature, food supply and pH.

Students design systems that use microbes to break down a water pollutant (in this case, sugar). They explore how temperature affects the rate of pollutant decomposition.

This lesson is the second of two that explore cellular respiration and population growth in yeasts. In the first lesson, students set up a simple way to indirectly observe and quantify the amount of respiration occurring in yeast-molasses cultures. Based on questions that arose during the first lesson and its associated activity, in this lesson students work in small groups to design experiments that will determine how environmental factors affect yeast population growth.

In this activity, students act as environmental engineers involved with the clean up of a toxic spill. Using bioremediation as the process, students select which bacteria they will use to eat up the pollutant spilled. Students learn how engineers use bioremediation to make organism degrade harmful chemicals. Engineers must make sure bacteria have everything they need to live and degrade contaminants for bioremediation to happen. Students learn about the needs of living things by setting up an experiment with yeast. The scientific method is reinforced as students must design the experiment themselves making sure they include a control and complete parts of a formal lab report.

Students are presented with information that will allow them to recognize that yeasts are unicellular organisms that are useful to humans. In fact, their usefulness is derived from the contrast between the way yeast cells and human cells respire. Specifically, while animal cells derive energy from the combination of oxygen and glucose and produce water and carbon dioxide as by-products, yeasts respire without oxygen. Instead, yeasts break glucose down and produce alcohol and carbon dioxide as their by-products. The lesson is also intended to provoke questions from students about the effects of alcohol on the human body, to which the teacher can provide objective answers.

Students set up a simple way to indirectly observe and quantify the amount of respiration occurring in yeast-molasses cultures. Each student adds a small amount of baking yeast to a test tube filled with diluted molasses. A second, smaller test tube is then placed upside-down inside the solution. As the yeast cells respire, the carbon dioxide they produce is trapped inside the inverted test tube, producing a growing bubble of gas that is easily observed and measured. Students are presented with the procedure for designing an effective experiment; they learn to think critically about experimental results and indirect observations of experimental events.

There's nothing quite like the smell of fresh-baked bread to make your mouth water. As any baker can tell you, you can't bake bread without yeast. This project makes clever use of bread dough to measure yeast reproduction three different ways, and investigates how well yeast grow with sugar substitutes as a food source.