Discovery-Based Learning in the Life Sciences

Kathleen M. Susman

• Publisher: Wiley-Blackwell
• Year: 2015
• Print ISBN: 9781118907566
• eBook ISBN: 9781118907245
• Edition: 1
• Topic: Biological Sciences
• Subtopic: Biology
• Index: Biological Sciences

For nearly a decade, scientists, educators and policy makers have issued a call to college biology professors to transform undergraduate life sciences education. As a gateway science for many undergraduate students, biology courses are crucial to addressing many of the challenges we face, such as climate change, sustainable food supply and fresh water and emerging public health issues.

While canned laboratories and cook-book approaches to college science education do teach students to operate equipment, make accurate measurements and work well with numbers, they do not teach students how to take a scientific approach to an area of interest about the natural world. Science is more than just techniques, measurements and facts; science is critical thinking and interpretation, which are essential to scientific research.

Discovery-Based Learning in the Life Sciences presents a different way of organizing and developing biology teaching laboratories, to promote both deep learning and understanding of core concepts, while still teaching the creative process of science.

In eight chapters, the text guides undergraduate instructors in creating their own discovery-based experiments. The first chapter introduces the text, delving into the necessity of science education reform. The chapters that follow address pedagogical goals and desired outcomes, incorporating discovery-based laboratory experiences, realistic constraints on such lab experiments, model scenarios, and alternate ways to enhance student understanding. The book concludes with a reflection on four imperatives in life science research-- climate, food, energy and health-- and how we can use these laboratory experiments to address them.

Discovery-Based Learning in the Life Sciences is an invaluable guide for undergraduate instructors in the life sciences aiming to revamp their curriculum, inspire their students and prepare them for careers as educated global citizens.

Chapter 1
The New Life Sciences

Biology in the twenty-first century is not your grandmother's or even your mother's biology. Disappearing are the highly specialized silos of biological knowledge – biochemistry, molecular biology, and cell biology – and the reductionistic imperative to start at the bottom and work our way up the organizational chart of life. Gone is the sense that to understand any biological phenomenon one must reduce it to its most basic level. Biologists are through with the need to view everything as an extreme close-up. From that vantage, life is featureless, static, and dull.

Our new biology is a complex, dynamic web of interactions. A nonlinear connectome. Sure the building blocks, the units of life, are still there. But the whole is more than the sum of the parts. Life is complicated, ever changing, and intriguing. Biologists need now be nimble, willing to question long-held beliefs about how organisms are related, how they change. Here's a quick example – the species concept. My generation learned that a species is a group of populations of related organisms that can potentially interbreed to produce viable offspring. Just a couple of questions will illustrate a few of the problems with this simple definition.

• What about the vast array of organisms that reproduce asexually?
• What about the organisms that look very different but can interbreed under some circumstances, but that normally don't?
• Or, where members of the same species are so different that they do not or cannot interbreed? Such as, for example, a Great Dane and a Chihuahua?

Newer species concepts include genetic, morphological, and ecological factors. Nowadays, phylogenetic trees, once thought to be a static tree of life (Figure 1.1) are instead considered working models, subject to revision (Figure 1.2) as we learn more.

Figure 1.1 A typical tree of life based on morphological characters. (Courtesy: Chris King. www.dhushara.com/book/unraveltree/unravel.htm.)

Figure 1.2 A phylogenetic tree of life no longer really a tree, more like a swirl, as in this representation of evolutionary relationships, based on a genomic study of the rRNA of 3,000 species by David Hillis, Derrick Zwicki and Robin Gutell from the University of Texas. (From Ciccarelli et al. (2006). Reprinted with permission from AAAS.)

The Challenges We Face in Teaching the New Biology

New technologies and paradigm-shifting approaches have dramatically transformed the life sciences over the past 20 years. Initially, college-level teaching accommodated this break-neck pace of discovery by adopting encyclopedic textbooks and streamlining lectures with full color slides instead of writing on the chalkboard. College instructors now fret about how to “cover” all the new material while continuing to teach the “classic” fundamental content from the 1980s and earlier. After all, the life sciences that we professors experienced began with the structure of DNA and the Central Dogma of DNA to RNA to protein and moved up levels of organization to consider Hardy–Weinberg's ideas of population-level evolutionary change and broader ecological principles such as succession. How could we not continue to teach those classic ideas and the elegant experiments that led to them?

At the same time, a growing field of pedagogical scholarship focuses on how students learn and retain information. The content-rich, lecture-style classroom experience, while still widely used, has fallen out of favor, making way for student-centered discussion and activities-based teaching strategies that, along with some lecture format, enhance the overall learning experience for our students.

Many professors of college introductory courses in the life sciences struggle to both teach all the new content (while retaining the “classics”) and incorporate new teaching and learning strategies.

Static for at least 50 years, introductory biology courses continue to be organized as the lecture period along with a weekly multihour laboratory component. In particular, the laboratory component has remained virtually unchanged for many college introductory biology courses. A glance at the commercially available introductory biology laboratory manuals on the market today reveals the same structure as those manuals published more than 20 years ago. Textbooks have also changed little except for vastly more content and much better illustrations and accompanying multimedia materials such as animations and videos. Authors of the newest textbooks have added question boxes and experimental research sidebars to enliven and provide some inquiry-based focus, but the same basic organization, the same march through content beginning with the molecules of life and ending with ecosystems, provides an overwhelming impression of biology as “a bunch of facts.”

There is too much information to “cover.” The move away from lecture to more student-centered, active approaches makes it even more difficult to “cover” content. The content overload has trickled down to high school and even middle school science classes. Children begin learning the language of science, but what's left by the time they get to college is just word recognition. In high school, they memorize lists of terms: “mitochondrion = fuel source of the cell;” with little depth about how that fuel is produced. Children (and many teachers) believe that hearing or memorizing terms and concepts equals learning. Been there, done that, they think. A quick quiz at the beginning of a college introductory biology course would soon reveal how little was remembered from high school, how little is understood. Like a language, Biology needs to be practiced; terms need to be used, spoken, written, and formed into new combinations.

And forget about laboratories and the process of science. One-time experiences and demonstrations do not teach students how science is done. If anything, these brief experiences convey false impressions that doing science is all about confirming what we already know. Students come away from these experiences believing that the ideas are “proven” by doing experiments. They don't see or experience the discovery process, the creative side of science. These misperceptions and attitudes then enter the introductory biology classroom at the college level, not to mention our society's views of science and scientists. Dimly remembered bits and pieces of facts and vocabulary words engrain falsehoods about how science is done. We have our work cut out for us, to be sure.

Visions of Change

Many college students take a course in introductory biology or life science as a requirement to satisfy distributional or science general education requirements. This means that introductory biology is a great opportunity to make a real difference in how science, life sciences in particular, is perceived. It's probably safe to say that most of us teaching introductory life sciences would agree that college-educated citizens and future policymakers and leaders need a firm understanding of the major concepts of biology. Climate change and its impacts are routinely in the news and are already affecting communities worldwide. Antibiotic-resistant superbugs and the global spread of new infectious diseases make the headlines. We all worry about getting cancer or want to age without Alzheimer's disease. Teaching biology in a way that promotes engagement rather than dismissal is thus a critical mission for college educators. Scientists and science education policy makers are urging life sciences educators to transform their teaching practices to better represent this new life science and to dispel the misconceptions about science. Because introductory and intermediate-level life sciences courses are the major training grounds for the vast majority of our educated citizens to be exposed to science in any form, there's a lot riding on them. We need to reinvent how we teach these courses.

Not all scientists agree that we need to change how we are teaching introductory biology, however. Some reason that scientists have been learning this way, through lectures that march up level of organization and through laboratories that introduce a new technique virtually every week, successfully for decades, so why do we need to change? “It worked for me. I'm a successful scientist and college professor. Why change?”

Perhaps the biggest reason urging us to change our approach to the teaching of life sciences is that it hasn't worked to increase general science literacy. In fact, the plod through a 1200-page textbook coupled with content-filled lectures and fact-laden examinations has been one of the biggest turn offs for most students for decades. Unfortunately, by the time most students get through middle school, they have turned off to science. Then, after high school biology, taught as facts and concepts to be memorized, most students close their minds to learning about biology. “Biology is boring.” These high-school students graduate and either go to college or enter the workplace, and many put their biology experiences behind them, never again to try to learn more about the life sciences, except what they glean from the evening news or the Discovery Channel.

College-level introductory biology as it is currently taught at most institutions does not succeed in re-opening these minds to the wonders of the living world, nor does it succeed in developing science literacy or appreciation. Those who go to college and take an introductory biology course often have their high school experiences further validated by the content and memorization-focused college lecture class structure and the multiple choice and scantron examinations. Laboratory experiences are little more than a disjointed series of different procedures, where students follow numbered lists of steps punctuated with questions: “What was the purpose of adding heat-killed peas to a tube? What does this experiment tell you about the influence of temperature on oxygen consumption during cellular respiration?” (Vodopich and Moore 10th Ed.; see Further Reading). The career biologists, physicians, and chemists simply persisted through those courses, despite the lackluster, fact-packed, memorization-focused approaches in class and the “cookbook”-style, procedure-focused laboratory sessions. The rest leave biology and science in droves, never looking back. We need to fundamentally change how we teach life sciences at the undergraduate level if we want our citizens and leaders to better appreciate the importance of scientific ways of thinking and to better understand the planet we live on and our effects on its inhabitants, including us.

Need for Structural Change

All students benefit from learning and understanding the scientific process. Because science is a part of all the major issues of modern life, appreciating how the scientific process works helps us critically evaluate what we read in the newspaper about the benefits or hazards of the latest fad diet or forming an opinion about the dangers and benefits of hydraulic fracturing. Understanding the creative process involved in discovering new knowledge about the world helps all citizens navigate the information-overload age, to assess the value or accuracy of the newest scientific claims or to appreciate the benefits to society of basic research and the importance of national funding of basic research. Applying skills of scientific literature searching and reading to the process of gathering evidence to understand questions in real life, such as medical care, financial management, and the adoption of new technologies, helps and empowers all of us to make informed decisions. These skills are the tool-kit for self-discovery. Engaging all students in science should therefore be a critical goal of all colleges and universities.

Is it fair to place the responsibility for the science literacy of our college graduates on a single introductory science course such as introductory biology? Of course not. In an ideal world, our college students would take more than one science course and would ideally get beyond introductory material into more intermediate or advanced-level thinking in a scientific discipline. Unfortunately, the vast majority of students will not penetrate a science curriculum more deeply than that first course. But we can certainly improve things with a single course. One outcome should be to inspire college students to take more than one science course. If our introductory curricula are designed to get students interested in learning more, we will be on the road to real change.

For over 20 years, STEM (Science, Techno...

Table of contents

• Cover
• Title Page
• Copyright
• Table of Contents
• Dedication
• Acknowledgments
• Chapter 1: The New Life Sciences
• Chapter 2: Changing Goals and Outcomes in Introductory Life Science Course Laboratories
• Chapter 3: Incorporating Discovery-Based Laboratory Experiences at the Introductory Level
• Chapter 4: The Constraints and Realities of Discovery-Based Laboratories
• Chapter 5: A Model Introductory Biology Course
• Chapter 6: Two Model Scenarios for an Intermediate-Level Life Science Course
• Chapter 7: Assessments and Why They Are Important
• Chapter 8: Fully Incorporating Vision and Change
• Appendix A: Laboratory Instructions for Behavioral Experiments Using Caenorhabditis elegans
• Appendix B: Instructions for Microscopy Workshop
• Index
• End User License Agreement