Student Success Guide TO ACCOMPANY WHAT IS LIFE? A GUIDE TO BIOLOGY WITH PHYSIOLOGY Fourth Edition by Jay Phelan Meredith S. Norris, M.S., Jennifer M. Warner, Ph.D., Department of Biology, The University of North Carolina at Charlotte, and Mark Manteuffel, Ph.D., St. Louis Community College W.H. Freeman and Company Macmillan Learning New York © 2018, 2015, 2013, 2010 by W.H. Freeman and Company www.macmillanlearning.com USED BY PERMISSION Chapter 1 SCIENTIFIC THINKING—YOUR BEST PATHWAY TO UNDERSTANDING THE WORLD Learning Objectives • • • • • • • • • • • • • • Describe the attributes of scientific thinking and biological literacy. Apply the scientific method to everyday situations. Explain how scientific thinking is both flexible and adaptable. Describe critical characteristics of useful hypotheses. Describe the attributes of the scientific method that allow it to be an effective tool. Design critical experiments to test hypotheses. Define scientific theory. Describe the characteristics of well-designed and controlled experiments. Describe ways to blind experiments. Describe the biases that can occur in scientific studies and ways to reduce those biases. Explain how statistics can add support to scientific claims. Identify pseudoscience and anecdotal evidence masked as scientific evidence. Discuss the limitations of science as a means to answer questions. Explain how hierarchical organization and evolution tie together all the major themes in biology. Chapter Outline I. · More Than Just a Collection of Facts, Science Is a Process for Understanding the World A. What is science? What is biology? Define science: · Define biology: · Define scientific literacy: © 2018, 2015, 2013, 2010 WH Freeman & Co. Used by permission. B. Biological literacy is essential in the modern world. · The development of biological literacy is important for understanding social, political, medical, and legal issues. This involves the ability to: 1. 2. 3. II. A Beginner’s Guide to Scientific Thinking A. Thinking like a scientist: how do you use the scientific method? · Although some people envision scientists in labs checking off the steps of the scientific method as they work, in reality the scientific method is more of a flexible set of guidelines for scientific thinking. The basic steps in the method include: 1. 2. 3. 4. 5. Describe empirical knowledge: Explain why scientific thinking is considered self-correcting: © 2018, 2015, 2013, 2010 WH Freeman & Co. Used by permission. Explain how scientific thinking rarely proceeds in a straight line, but in practice is much more flexible and adaptable: B. Step 1: Make observations. The first step of science is making observations about the world. Observations involve looking for interesting patterns or cause-and-effect relationships. C. Step 2: Formulate a hypothesis. · A phenomena. · is defined as tentative explanation for observed A useful hypothesis must be able to achieve two goals: 1. 2. · A hypothesis that is stated such that there is not a relationship between two variables is referred to as a(n) hypothesis. · In terms of hypotheses, it is best to state that they can be proven. by data instead of D. Step 3: Devise a testable prediction. · Useful hypotheses involve testable predictions. Hypotheses can be refined and adjusted as needed. E. Step 4: Conduct a critical experiment. An experiment that makes it possible to determine whether a particular hypothesis is better than alternative hypotheses is called a(n) experiment. · · Explain how a placebo is used in a critical experiment: © 2018, 2015, 2013, 2010 WH Freeman & Co. Used by permission. F. Step 5: Draw conclusions; make revisions. · Drawing conclusions from experimentation provides opportunity for revision. In your own words, explain why it is important to include revision in this process: G. When do hypotheses become theories, and what are theories? · Hypotheses with overwhelming experimental support can evolve into theories. Although the common use of the term theory refers to a hunch or tentative hypothesis, explain how the scientific use of theory means something much more: III. Well-Designed Experiments Are Essential to Testing Hypotheses · Experimental design is a critical part of the scientific process. Experiments that are carefully and purposefully designed are most likely to show cause-and-effect relationships between variables. Additionally, it is critical that experimental results can be reproduced when the experiment is repeated. A. Controlling variables makes experiments more powerful. • Define each of the following elements of experiments: 1. Treatment 2. Experimental group 3. Control group 4. Variables a. Independent variable b. Dependent variable © 2018, 2015, 2013, 2010 WH Freeman & Co. Used by permission. • Why is it so important to control variables in an experiment? • The use of placebos can lead to the placebo effect. Explain what this means: Explain why the placebo effect amplifies the need for an appropriate control group: • In a blind experimental design, the are not aware whether they are receiving the treatment or not. In a double-blind experimental design, neither the nor the are aware of which subjects are receiving the treatment. • Explain what a randomized experimental design is: B. This Is How We Do It: Is arthroscopic surgery for arthritis of the knee beneficial? • Did this study utilize a blinded experimental design? Explain: • Did this study utilize a randomized experimental design? Explain: • Although this particular study would not be an easy one to replicate, explain why scientific studies should have an expectation of reproducible results: © 2018, 2015, 2013, 2010 WH Freeman & Co. Used by permission. C. We’ve got to watch out for our biases. People, including scientists, have biases—sometimes subconscious—that influence their behavior, including the collection and interpretation of data. n n Explain how proper controls in experiments can minimize the influence of bias: n What is replication, and how does it improve scientific thinking? IV. Scientific Thinking Can Help Us Make Wise Decisions · The use of the scientific method and a critical approach to reviewing evidence can help us make sense of data and anecdotal evidence, as well as help us distinguish science from pseudoscience. A. Visual displays of data can help us understand and explain phenomena. • Which forms of displaying data are used most frequently in biology? • Describe each of the common elements found in most visual displays of data: 1. Title 2. x-axis 3. y-axis 4. Independent variable 5. Dependent variable 6. Data points B. Statistics can help us make decisions. • How can statistics put data in context to determine if a hypothesis is supported or not? © 2018, 2015, 2013, 2010 WH Freeman & Co. Used by permission. • When evaluating statistical analysis of data in order to determine whether the treatment had a significant effect or not, we are looking for a difference between the experimental and control groups with a variation within each group. Correlational studies look at relationships between different variables. A correlation is when an increase in one variable leads to an increase in another variable. A correlation occurs when an increase in one variable leads to a decrease in another variable. • C. Pseudoscience and misleading anecdotal evidence can obscure the truth. • People are often taken in by false scientific claims. The two most common ways to mislead the public are by using pseudoscience and anecdotal evidence. Describe what these terms mean: o Pseudoscience o Anecdotal evidence • Describe an example of misleading scientific evidence in the form of pseudoscience and anecdotal evidence: o Pseudoscience o Anecdotal evidence D. There are limits to what science can do. • Although we often talk about what science is, we don’t always hear so much about what science is not. Science, just like other disciplines, has limitations to the sorts of questions it can answer. • Give several examples of questions that science cannot answer: © 2018, 2015, 2013, 2010 WH Freeman & Co. Used by permission. V. On the Road to Biological Literacy: What Are the Major Themes in Biology? · Biology is the study of life. List and describe the major characteristics similar to all living organisms: · As you progress through the course, you will learn about many differing aspects of biology. However, two common themes will prevail throughout the course. Explain these major themes: o Hierarchical organization o Evolution © 2018, 2015, 2013, 2010 WH Freeman & Co. Used by permission. Testing and Applying Your Understanding 1. You are studying the effects of artificial sweetener on mice. Four groups of mice consume different amounts of sweetener in their food. How much sweetener would the control group receive? Explain your answer. 2. You are testing treatments for cancer patients and find that 75% of patients respond very well to a particular treatment, while 25% show no improvement or decline in health after taking the experimental treatment. What should you do next? 3. It is notoriously difficult to perform unbiased studies when human subjects are used. When governmental agencies (such as the FDA) are trying to determine the validity of scientific claims, they very closely examine the method in which the experimental studies were done. Name several things that would be important in evaluating how the studies were performed. 4. There are many nutritional supplements on the market that allege that they can cause weight loss without dieting or exercise. Suppose you read a claim that a particular supplement causes weight loss and you are given the following information: • • • • • People were weighed at the beginning of the study. People were asked to take two pills per day. People were weighed at the end of the study. People who took the supplement for four weeks seemed to have lost some weight at the end of the study. It was concluded that the supplement is helpful for weight loss. This study has some obvious holes in it. Explain five things that could be done to this study to improve it. Do not assume any information other than what has been provided. © 2018, 2015, 2013, 2010 WH Freeman & Co. Used by permission. 5. Explain the importance of placebos in human clinical trials. Are placebos a form of treatment? Explain your answer. 6. Suppose that data are collected that appear to link two variables. The data suggest that as hours of sleep per night decline, reaction times to various stimuli also decrease. Is this an example of a positive or negative correlation? Explain your answer. 7. Your roommate exhibits a particular ritual before each exam she takes, because she is convinced that this ritual ensures her success on exams. She eats the same meal the night before, goes to bed at exactly the same time, listens to the same song the morning of the exam, and always wears the same sweatshirt to the exam. Design an experiment that will help to determine if her ritual does, in fact, enhance her exam performance. 8. It is common to see statistics manipulated in the media and in marketing in order to convince people that a certain treatment has a more pronounced effect than it really does. An example is a weight-loss supplement that is advertised to have caused 514% more weight loss than a competing product. What information do you need to know in order to put this statistic in context? © 2018, 2015, 2013, 2010 WH Freeman & Co. Used by permission.