{"id":6018,"date":"2018-03-20T19:04:07","date_gmt":"2018-03-20T19:04:07","guid":{"rendered":"https:\/\/courses.lumenlearning.com\/ivytech-wmopen-nmbiology\/chapter\/the-study-of-biology\/"},"modified":"2023-07-11T17:20:10","modified_gmt":"2023-07-11T17:20:10","slug":"the-study-of-biology","status":"publish","type":"chapter","link":"https:\/\/courses.lumenlearning.com\/ivytech-wmopen-nmbiology\/chapter\/the-study-of-biology\/","title":{"raw":"The Study of Biology","rendered":"The Study of Biology"},"content":{"raw":"<h2>Describe biology as a science and identify the key components of scientific inquiry<\/h2>\r\nThe scope of biology is vast. Biologists may study anything from the microscopic (Figure 1a)\u00a0or submicroscopic view of a cell to ecosystems (Figure 1b) and the whole living planet.\r\n\r\n[caption id=\"attachment_1120\" align=\"aligncenter\" width=\"1076\"]<img class=\"wp-image-1120 size-full\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/3116\/2018\/03\/20190355\/figure01_01.jpg\" alt=\"Photo A depicts round colonies of blue-green algae. Each algae cell is about 5 microns across. Photo B depicts round fossil structures called stromatalites along a watery shoreline.\" width=\"1076\" height=\"432\" \/> Figure 1. (a) Formerly called blue-green algae, these cyanobacteria, shown here at 300\u00d7 magnification under a light microscope, are some of Earth's oldest life forms. (b) These stromatolites along the shores of Lake Thetis in Western Australia are ancient structures formed by the layering of cyanobacteria in shallow waters.[\/caption]\r\n\r\nListening to the daily news, you will quickly realize how many aspects of biology are discussed every day. You may hear about <em>E.\u00a0coli\u00a0(Escherichia coli)\u00a0<\/em>outbreaks in spinach or\u00a0listeria\u00a0contamination in ice cream. Or you may hear about\u00a0efforts toward finding a cure for Ebola, Alzheimer's disease, and cancer. On a global scale, many researchers are committed to finding ways to protect the planet, solve environmental issues, and reduce the effects of climate change. All of these diverse endeavors are related to different facets of the discipline of biology.\r\n\r\nRegardless of their particular focus of study, all\u00a0biologists\u00a0use the same methodology as they seek new discoveries: scientific inquiry.\r\n<div class=\"textbox learning-objectives\">\r\n<h3>Learning Objectives<\/h3>\r\n<ul>\r\n \t<li>Identify the main branches of biology<\/li>\r\n \t<li>Describe \"scientific inquiry\" and identify its scope of coverage<\/li>\r\n \t<li>Form a hypothesis and use it to design a scientific experiment<\/li>\r\n \t<li>Analyze simple data and graphed results<\/li>\r\n<\/ul>\r\n<\/div>\r\n<h2>\u00a0The Branches of Biology<\/h2>\r\nThe scope of biology is broad and therefore contains many branches and sub-disciplines. Biologists may pursue one of those sub-disciplines and work in a more focused field. For instance, molecular biology and biochemistry study biological processes at the molecular and chemical level, including interactions among molecules such as DNA, RNA, and proteins, as well as the way they are regulated. Microbiology, the study of microorganisms, is the study of the structure and function of single-celled organisms. It is quite a broad branch itself, and depending on the subject of study, there are also microbial physiologists, ecologists, and geneticists, among others.\r\n<div class=\"textbox key-takeaways\">\r\n<h3>Forensic\u00a0Science<\/h3>\r\n[caption id=\"attachment_1828\" align=\"alignright\" width=\"300\"]<img class=\"wp-image-1828 size-medium\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/110\/2016\/05\/03213712\/Figure_01_02_191-300x209.jpg\" alt=\"A scientist working in the lab.\" width=\"300\" height=\"209\" \/> Figure 2. This forensic scientist works in a DNA extraction room at the U.S. Army Criminal Investigation Laboratory at Fort Gillem, GA. (credit: United States Army CID Command Public Affairs)[\/caption]\r\n\r\nForensic science is the application of science to answer questions related to the law. Biologists as well as chemists and biochemists can be forensic scientists. Forensic scientists provide scientific evidence for use in courts, and their job involves examining trace materials associated with crimes. Interest in forensic science has increased in the last few years, possibly because of popular television shows that feature forensic scientists on the job. Also, the development of molecular techniques and the establishment of DNA databases have expanded the types of work that forensic scientists can do.\r\n\r\nTheir job activities are primarily related to crimes against people such as murder, rape, and assault. Their work involves analyzing samples such as hair, blood, and other body fluids and also processing DNA (Figure 2) found in many different environments and materials.\r\n\r\nForensic scientists also analyze other biological evidence left at crime scenes, such as insect larvae or pollen grains. Students who want to pursue careers in forensic science will most likely be required to take chemistry and biology courses as well as some intensive math courses.\r\n\r\n<\/div>\r\nAnother field of biological study, neurobiology, studies the biology of the nervous system, and although it is considered a branch of biology, it is also recognized as an interdisciplinary field of study known as neuroscience. Because of its interdisciplinary nature, this sub-discipline studies different functions of the nervous system using molecular, cellular, developmental, medical, and computational approaches.\r\n\r\n[caption id=\"attachment_1519\" align=\"alignright\" width=\"350\"]<img class=\"wp-image-1519\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/3116\/2018\/03\/20190401\/Figure_01_02_18.jpg\" alt=\"People sitting in the dirt with digging tools.\" width=\"350\" height=\"269\" \/> Figure 3. Researchers work on excavating dinosaur fossils at a site in Castell\u00f3n, Spain. (credit: Mario Modesto)[\/caption]\r\n\r\nPaleontology, another branch of biology, uses fossils to study life's history (Figure 3). Zoology and botany are the study of animals and plants, respectively. Biologists can also specialize as biotechnologists, ecologists, or physiologists, to name just a few areas. This is just a small sample of the many fields that biologists can pursue.\r\n\r\nBiology is the culmination of the achievements of the natural sciences from their inception to today. Excitingly, it is the cradle of emerging sciences, such as the biology of brain activity, genetic engineering of custom organisms, and the biology of evolution that uses the laboratory tools of molecular biology to retrace the earliest stages of life on earth. A scan of news headlines\u2014whether reporting on immunizations, a newly discovered species, sports doping, or a genetically modified food\u2014demonstrates the way biology is active in and important to our everyday world.\r\n<h2>Scientific Inquiry<\/h2>\r\nScience deals with testable knowledge about physical phenomena in the universe. The goal of science is to understand how the universe works. Biology focuses on understanding living things. To gain knowledge about nature and physical phenomena, scientists use a particular approach called \u201cscientific inquiry.\u201d\r\n\r\nScientific inquiry is the best approach we have to understanding the natural world and predicting natural phenomena. Evidence for this claim can be found in the successes of science-based technologies. Take medicine, for example. Prior to the 1700s, most medical practices were based on folk traditions or on ideas promoted by religious leaders. Some of these prescientific remedies worked, but the process for discovering new treatments was a slow and haphazard system of trial and error. Ineffective treatments were often accepted simply because there was no clear procedure for evaluating them. Today, with science-based medicine and public health practices, we have gained unprecedented control over threats to our health. According to the Centers for Disease Control, the average life expectancy in the United States has increased by more than 30 years since 1900.\r\n\r\nScientific inquiry has not displaced faith, intuition, and dreams. These traditions and ways of knowing have emotional value and provide moral guidance to many people. But hunches, feelings, deep convictions, old traditions, or dreams cannot be accepted directly as scientifically valid. Instead, science limits itself to ideas that can be tested through verifiable observations. Supernatural claims that events are caused by ghosts, devils, God, or other spiritual entities cannot be tested in this way.\r\n<div class=\"textbox exercises\">\r\n<h3>Practice Question<\/h3>\r\nYour friend sees this image of a circle of mushrooms and excitedly tells you it was caused by fairies dancing in a circle on the grass the night before. Can your friend\u2019s explanation be studied using the process of science?\r\n\r\n[caption id=\"\" align=\"aligncenter\" width=\"350\"]<img src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/3116\/2018\/03\/20190405\/mushrooms.png\" alt=\"There are several mushrooms growing together in the pattern of a circular ring\" width=\"350\" height=\"262\" \/> Figure 4. A fairy ring[\/caption]\r\n\r\n[reveal-answer q=\"665464\"]<strong>Show Answer<\/strong>[\/reveal-answer]\r\n[hidden-answer a=\"665464\"]In theory, you might try to observe the fairies. But fairies are magical or supernatural beings. We have never observed them using any verifiable method, so scientists agree that they cannot be studied using scientific tools. Instead, science has an explanation supported by strong evidence: \u201cfairy rings\u201d result when a single colony of fungus spreads out into good habitat over a period of many years. The core area is clear of mushrooms because the soil nutrients have been partly depleted there. This idea can be evaluated with repeated observations over time using chemical soil tests and other verifiable measurements.[\/hidden-answer]\r\n\r\n<\/div>\r\n<h2>Experiments and Hypotheses<\/h2>\r\nNow we'll\u00a0focus on the methods of scientific inquiry. Science often involves making\u00a0observations and developing hypotheses. Experiments and further observations are often used to test the hypotheses.\r\n\r\nA scientific experiment is a carefully organized procedure in which the scientist intervenes in a system to change something, then observes the result of the change. Scientific inquiry often involves doing experiments, though not always. For example, a scientist studying the mating behaviors of ladybugs might begin with detailed observations of ladybugs mating in their natural habitats. While this research may not be experimental, it is scientific: it involves careful and verifiable observation of the natural world. The same scientist might then treat some of the ladybugs with a hormone hypothesized to trigger mating and observe whether these ladybugs mated sooner or more often than untreated ones. This would qualify as an experiment because the scientist is now making a change in the system and observing the effects.\r\n<h3>Forming a Hypothesis<\/h3>\r\nWhen conducting scientific experiments, researchers develop hypotheses to guide experimental design. A\u00a0hypothesis is a suggested explanation that is both testable and falsifiable. You must be able to test your hypothesis, and it must be possible to prove your hypothesis true or false.\r\n\r\nFor example, Michael\u00a0observes that maple trees lose their leaves in the fall. He might then propose a possible explanation for this observation: \u201ccold weather causes maple trees to lose their leaves in the fall.\u201d This statement is testable. He\u00a0could grow maple trees in a warm enclosed environment such as a greenhouse and see if their leaves still dropped in the fall. The hypothesis is also falsifiable. If the leaves still dropped in the warm environment, then clearly temperature was not the main factor in causing maple leaves to drop in autumn.\r\n\r\nIn the Try It\u00a0below, you can practice recognizing scientific hypotheses. As you consider each statement, try to think as a scientist would: can I test this hypothesis with observations or experiments? Is the statement falsifiable? If the answer to either of these questions is \u201cno,\u201d the statement is not a valid scientific hypothesis.\r\n<div class=\"textbox exercises\">\r\n<h3>Practice Questions<\/h3>\r\nDetermine whether each following statement is a scientific hypothesis.\r\n\r\nAir pollution from automobile exhaust can trigger symptoms in people with asthma.\r\n<ol style=\"list-style-type: lower-alpha;\">\r\n \t<li>No. This statement is not testable or falsifiable.<\/li>\r\n \t<li>No. This statement is not testable.<\/li>\r\n \t<li>No. This statement is not falsifiable.<\/li>\r\n \t<li>Yes. This statement is testable and falsifiable.<\/li>\r\n<\/ol>\r\n[reveal-answer q=\"429550\"]<strong>Show Answer<\/strong>[\/reveal-answer]\r\n[hidden-answer a=\"429550\"]d: Yes. This statement is testable and falsifiable. This could be tested with a number of different kinds of observations and experiments, and it is possible to gather evidence that indicates that air pollution is not linked with asthma.\r\n\r\n[\/hidden-answer]\r\n\r\nNatural disasters, such as tornadoes, are punishments for bad thoughts and behaviors.\r\n<ol style=\"list-style-type: lower-alpha;\">\r\n \t<li>No. This statement is not testable or falsifiable.<\/li>\r\n \t<li>No. This statement is not testable.<\/li>\r\n \t<li>No. This statement is not falsifiable.<\/li>\r\n \t<li>Yes. This statement is testable and falsifiable.<\/li>\r\n<\/ol>\r\n[reveal-answer q=\"74245\"]Show Answer[\/reveal-answer]\r\n[hidden-answer a=\"74245\"]\r\n\r\na: No. This statement is not testable or falsifiable. \u201cBad thoughts and behaviors\u201d are excessively vague and subjective variables that would be impossible to measure or agree upon in a reliable way. The statement might be \u201cfalsifiable\u201d if you came up with a counterexample: a \"wicked\" place that was not punished by a natural disaster. But some would question whether the people in that place were really wicked, and others would continue to predict that a natural disaster was bound to strike that place at some point. There is no reason to suspect that people's immoral behavior affects the weather unless you bring up the intervention of a supernatural being, making this idea even harder to test.\r\n\r\n[\/hidden-answer]\r\n\r\n<\/div>\r\n<h3>Testing a Vaccine<\/h3>\r\nLet's\u00a0examine the scientific process by discussing an actual scientific experiment conducted by researchers at the University of Washington. These researchers investigated whether a vaccine may reduce the incidence of the human papillomavirus (HPV). The experimental process and results were published in an article titled, \"<a href=\"http:\/\/www.ncbi.nlm.nih.gov\/pubmed\/12444178\" target=\"_blank\" rel=\"noopener\">A controlled trial of a human papillomavirus type 16 vaccine<\/a>.\"\r\n\r\nPreliminary observations made by the researchers who conducted the HPV experiment are listed below:\r\n<ul>\r\n \t<li>Human papillomavirus (HPV) is the most common sexually transmitted virus in the United States.<\/li>\r\n \t<li>There are about 40 different types of HPV. A significant number of people that have HPV are unaware of it because many of these viruses cause no symptoms.<\/li>\r\n \t<li>Some types of HPV can cause cervical cancer.<\/li>\r\n \t<li>About 4,000 women a year die of cervical cancer in the United States.<\/li>\r\n<\/ul>\r\n<div class=\"textbox exercises\">\r\n<h3>Practice Question<\/h3>\r\nResearchers have developed a potential vaccine against HPV and want to test it.\u00a0What is the first testable hypothesis that the researchers should study?\r\n<ol style=\"list-style-type: lower-alpha;\">\r\n \t<li>HPV causes cervical cancer.<\/li>\r\n \t<li>People should not have unprotected sex with many partners.<\/li>\r\n \t<li>People who get the vaccine will not get HPV.<\/li>\r\n \t<li>The HPV vaccine will protect people against cancer.<\/li>\r\n<\/ol>\r\n[reveal-answer q=\"20917\"]<strong>Show Answer<\/strong>[\/reveal-answer]\r\n[hidden-answer a=\"20917\"]Hypothesis A is not the best choice because this information is already known from previous studies. Hypothesis B\u00a0is not testable because scientific hypotheses are not value statements; they do not include judgments like \u201cshould,\u201d\u00a0\u201cbetter than,\u201d etc. Scientific evidence certainly might support this value judgment, but a hypothesis\u00a0would take a different form: \u201cHaving unprotected sex with many partners increases a person\u2019s risk for\u00a0cervical cancer.\u201d Before the researchers can test if the vaccine protects against cancer (hypothesis D), they want to test if it\u00a0protects against the virus. This statement will make an excellent hypothesis for the next study. The researchers should first test hypothesis C\u2014whether or not the new vaccine can prevent HPV.[\/hidden-answer]\r\n\r\n<\/div>\r\n<h3>Experimental Design<\/h3>\r\nYou\u2019ve successfully identified a hypothesis for the University of Washington\u2019s study on HPV: People who get the HPV vaccine will not get HPV.\r\n\r\nThe next step is to design an experiment that will test this hypothesis. There are several important factors to consider when designing a scientific experiment. First, scientific experiments must have an experimental group. This is the group that receives the experimental treatment necessary to address the hypothesis.\r\n\r\nThe experimental group receives the vaccine, but how can we know if the vaccine made a difference? Many things may change HPV infection rates in a group of people over time. To clearly show that the vaccine was effective in helping the experimental group, we need to include in our study an otherwise similar control group that does not get the treatment. We can then compare the two groups and determine if the vaccine made a difference. The control group shows us what happens in the absence of the factor under study.\r\n\r\nHowever, the control group cannot get \u201cnothing.\u201d Instead, the control group often receives a placebo. A <em>placebo<\/em> is a procedure that has no expected therapeutic effect\u2014such as giving a person a sugar pill or a shot containing only plain saline solution with no drug. Scientific studies have shown that the \u201cplacebo effect\u201d can alter experimental results because when individuals are told that they are or are not being treated, this knowledge can alter their actions or their emotions, which can then alter the results of the experiment.\r\n\r\nMoreover, if the doctor knows which group a patient is in, this can also influence the results of the experiment. Without saying so directly, the doctor may show\u2014through body language or other subtle cues\u2014his or her views about whether the patient is likely to get well. These errors can then alter the patient\u2019s experience and change the results of the experiment. Therefore, many clinical studies are \u201cdouble blind.\u201d In these studies, neither the doctor nor the patient knows which group the patient is in until all experimental results have been collected.\r\n\r\nBoth placebo treatments and double-blind procedures are designed to prevent bias. Bias is any systematic error that makes a particular experimental outcome more or less likely. Errors can happen in any experiment: people make mistakes in measurement, instruments fail, computer glitches can alter data. But most such errors are random and don\u2019t favor one outcome over another. Patients\u2019 belief in a treatment can make it more likely to appear to \u201cwork.\u201d Placebos and double-blind procedures are used to level the playing field so that both groups of study subjects are treated equally and share similar beliefs about their treatment.\r\n<div class=\"textbox exercises\">\r\n<h3>Practice Questions<\/h3>\r\nThe scientists who are researching the effectiveness of the HPV vaccine will test their hypothesis by separating 2,392 young women into two groups: the control group and the experimental group. Answer the following questions about these two groups.\r\n<ol>\r\n \t<li>Which of the following groups most likely represents the control group?\r\n<ol style=\"list-style-type: lower-alpha;\">\r\n \t<li>This group is given a placebo.<\/li>\r\n \t<li>This group is deliberately infected with HPV.<\/li>\r\n \t<li>This group is given nothing.<\/li>\r\n \t<li>This group is given the HPV vaccine.<\/li>\r\n<\/ol>\r\n<\/li>\r\n \t<li>Which of the following groups most likely represents the experimental group?\r\n<ol style=\"list-style-type: lower-alpha;\">\r\n \t<li>This group is given a placebo.<\/li>\r\n \t<li>This group is deliberately infected with HPV.<\/li>\r\n \t<li>This group is given nothing.<\/li>\r\n \t<li>This group is given the HPV vaccine.<\/li>\r\n<\/ol>\r\n<\/li>\r\n<\/ol>\r\n[reveal-answer q=\"918962\"]<strong>Show Answers<\/strong>[\/reveal-answer]\r\n[hidden-answer a=\"918962\"]\r\n<ol>\r\n \t<li>a: This group is given a placebo.\u00a0A placebo will be a shot, just like the HPV vaccine, but it will have no active ingredient. It may\u00a0change peoples\u2019 thinking or behavior to have such a shot given to them, but it will not stimulate the\u00a0immune systems of the subjects in the same way as predicted for the vaccine itself.<\/li>\r\n \t<li>d: This group is given the HPV vaccine.\u00a0The experimental group will receive the HPV vaccine and researchers will then be able to\u00a0see if it works, when compared to the control group.<\/li>\r\n<\/ol>\r\n[\/hidden-answer]\r\n\r\n<\/div>\r\n<h3>Experimental Variables<\/h3>\r\nA variable is a characteristic of a subject (in this case, of a person in the study) that can vary over time or among individuals. Sometimes a variable takes the form of a category, such as male or female; often a variable can be measured precisely, such as body height. Ideally, only one variable is different between the control group and the experimental group in a scientific experiment. Otherwise, the researchers will not be able to determine which variable caused any differences seen in the results. For example, imagine that the people in the control group were, on average, much more sexually active than the people in the experimental group. If, at the end of the experiment, the control group had a higher rate of HPV infection, could you confidently determine why? Maybe the experimental subjects were protected by the vaccine, but maybe they were protected by their low level of sexual contact.\r\n\r\nTo avoid this situation, experimenters make sure that their subject groups are as similar as possible in all variables except for the variable that is being tested in the experiment. This variable, or factor, will be deliberately changed in the experimental group. The one variable that is different between the two groups is called the independent variable. An independent variable is known or hypothesized to cause some outcome. Imagine an educational researcher investigating the effectiveness of a new teaching strategy in a classroom. The experimental group receives the new teaching strategy, while the control group receives the traditional strategy. It is the teaching strategy that is the independent variable in this scenario. In an experiment, the independent variable is the variable that the scientist deliberately changes or imposes on the subjects.\r\n\r\nDependent variables are known or hypothesized consequences; they are the effects that result from changes or differences in an independent variable. In an experiment, the dependent variables are those that the scientist measures before, during, and particularly at the end of the experiment to see if they have changed as expected. The dependent variable must be stated so that it is clear how it will be observed or measured. Rather than comparing \u201clearning\u201d among students (which is a vague and difficult to measure concept), an educational researcher might choose to compare test scores, which are very specific and easy to measure.\r\n\r\nIn any real-world example, many, many variables MIGHT affect the outcome of an experiment, yet only one or a few independent variables can be tested. Other variables must be kept as similar as possible between the study groups and are called <em>control variables<\/em>. For our educational research example, if the control group consisted only of people between the ages of 18 and 20 and the experimental group contained people between the ages of 30 and 35, we would not know if it was the teaching strategy or the students' ages that played a larger role in the results. To avoid this problem, a good study will be set up so that each group contains students with a similar age profile. In a well-designed educational research study, student age will be a controlled variable, along with other possibly important factors like gender, past educational achievement, and pre-existing knowledge of the subject area.\r\n<div class=\"textbox exercises\">\r\n<h3>Practice Questions<\/h3>\r\nWhat is the independent variable in this experiment?\r\n<ol style=\"list-style-type: lower-alpha;\">\r\n \t<li>Sex (all of the subjects will be female)<\/li>\r\n \t<li>Presence or absence of the HPV vaccine<\/li>\r\n \t<li>Age<\/li>\r\n \t<li>Presence or absence of HPV (the virus)<\/li>\r\n<\/ol>\r\n[reveal-answer q=\"68680\"]Show Answer[\/reveal-answer]\r\n[hidden-answer a=\"68680\"]Answer b. Presence or absence of the HPV vaccine. This is the variable that is different between the control and the experimental groups.\u00a0All the subjects in this study are female, so this variable is the same in all groups.\u00a0In a well-designed study, the two groups will be of similar age.\u00a0The presence or absence of the virus is what the researchers will measure at the <em>end<\/em>\u00a0of the experiment. Ideally the two\u00a0groups will both be HPV-free at the start of the experiment.\r\n\r\n[\/hidden-answer]\r\n\r\nList three control variables other than age.\r\n\r\n[practice-area rows=\"3\"][\/practice-area]\r\n[reveal-answer q=\"903121\"]Show Answer[\/reveal-answer]\r\n[hidden-answer a=\"903121\"]Some possible control variables would be: general health of the women, sexual activity, lifestyle, diet,\u00a0socioeconomic status, etc.\r\n\r\n[\/hidden-answer]\r\n\r\nWhat is the dependent variable in this experiment?\r\n<ol style=\"list-style-type: lower-alpha;\">\r\n \t<li>Sex (male or female)<\/li>\r\n \t<li>Rates of HPV infection<\/li>\r\n \t<li>Age (years)<\/li>\r\n<\/ol>\r\n[reveal-answer q=\"907103\"]Show Answer[\/reveal-answer]\r\n[hidden-answer a=\"907103\"]Answer b. Rates of HPV infection. The researchers will measure how many individuals got infected with HPV after a given\u00a0period of time.[\/hidden-answer]\r\n\r\n<\/div>\r\n<h2>Interpreting Results<\/h2>\r\n<h3>Gathering Data<\/h3>\r\nAfter the experiment is completed, the data gathered are carefully interpreted. This involves the measurement of the dependent variable. In the case of our HPV experiment, remember, the dependent variable is the rate of HPV infection.\r\n<div class=\"textbox exercises\">\r\n<h3>Practice Question<\/h3>\r\nThe researchers found that, of the 1,200 women in the control group, nine were infected with HPV at the end of the study. Of the 1,200 women in the experimental group, zero were infected with HPV. Does this result support the original hypothesis, that the HPV vaccine would reduce HPV infection?\r\n\r\n[practice-area rows=\"2\"][\/practice-area]\r\n[reveal-answer q=\"318356\"]<strong>Show Answer<\/strong>[\/reveal-answer]\r\n[hidden-answer a=\"318356\"]The results demonstrate that fewer individuals who got the vaccine were infected with HPV when compared to the number of infected individuals who did not get the vaccine. This supports the hypothesis that the new vaccine protects against HPV.[\/hidden-answer]\r\n\r\n<\/div>\r\n<h3>Significance<\/h3>\r\nAlthough the HPV study suggests that the vaccine protects against infection by HPV, is the finding significant? In science, as in life, things can happen for many different reasons. A convincing study will rule out \u201cluck\u201d (random chance) as an explanation for the results. Strong results are said to be significant: very unlikely to occur by chance or random events.\r\n\r\nWhether the outcome is significant often depends on the size of study; the larger the number of individuals enrolled, the more convincing the results are likely to be. For example, imagine only 10 women were enrolled in the study. In the control group, 2 in 5 of the women became infected. In the experimental group, 0 in 5 were infected. At first you might think this proves the vaccine\u2019s effectiveness, but it is NOT a convincing or significant result. Why not? Random events could easily explain the difference between the groups. For example, perhaps none of the five women in the experimental group were sexually active over the study period. They therefore stood no chance of acquiring HPV. The vaccine might appear to work, but a skeptical reader could account for the results by proposing many other scenarios.\r\n\r\nHowever, imagine if the same study were done with 10,000 women, and the infection rates were 2,000 of 5,000 in the control group and zero of 5,000 in the experimental group. Random events would be spread out among a very large group of people in this study; on average, the two big groups should have similar sexual behavior and other factors influencing infection rates. If there is a big difference at the end of the study, it is very unlikely that <em class=\"italic\">this<\/em> result occurred by random chance.\r\n\r\nStatistical analyses did support the significance of the HPV vaccine result.\r\n<div class=\"textbox exercises\">\r\n<h3>Practice Question<\/h3>\r\nResearchers reported significant results from the HPV vaccine experiment. If the results had NOT\u00a0been significant, what would this mean?\r\n\r\n[practice-area rows=\"2\"][\/practice-area]\r\n[reveal-answer q=\"185159\"]<strong>Show Answer<\/strong>[\/reveal-answer]\r\n[hidden-answer a=\"185159\"]If the results from this experiment were not significant, it would mean that the number of women who did\u00a0not get HPV after being vaccinated was the same number that would be seen just from random chance.[\/hidden-answer]\r\n\r\n<\/div>\r\nAfter the results are interpreted and conclusions are drawn, researchers often return to their work and begin asking further questions. In this way, scientific inquiry is a powerful tool for exploration.\r\n<div class=\"textbox exercises\">\r\n<h3>Practice Question<\/h3>\r\nWhat would be a good next question the HPV vaccine researchers may want to test? (<i>More than one answer is correct.<\/i>)\r\n<ol style=\"list-style-type: lower-alpha;\">\r\n \t<li>At what age is this vaccine most effective (what age group should be vaccinated)?<\/li>\r\n \t<li>Does the HPV vaccine protect males as well as females?<\/li>\r\n \t<li>Does protecting against HPV protect against cancer?<\/li>\r\n \t<li>Should young girls be forced to get the vaccine against their parents' wishes?<\/li>\r\n<\/ol>\r\n[reveal-answer q=\"689643\"]<strong>Show Answers<\/strong>[\/reveal-answer]\r\n[hidden-answer a=\"689643\"]\r\n\r\nQuestions a, b, anc c are the best questions. These questions are currently being studied.\r\n\r\nAlthough question d\u00a0is important and\u00a0has generated a lot of political heat, it is not a\u00a0scientific question. Scientists can predict what will happen if girls are or are not vaccinated, but cannot\u00a0decide whether disease risk or parental authority is more important.\r\n\r\n[\/hidden-answer]\r\n\r\n<\/div>\r\n<h3>Graphing Data<\/h3>\r\nWatch this ten-minute video about simple graphing:\r\n\r\nhttps:\/\/youtu.be\/9BkbYeTC6Mo\r\n<div class=\"textbox exercises\">\r\n<h3>Check Your Understanding<\/h3>\r\nWhat discipline of biology is focused on life\u2019s history?\r\n<ul>\r\n \t<li>paleontology<\/li>\r\n \t<li>forensic botany<\/li>\r\n \t<li>neurobiology<\/li>\r\n<\/ul>\r\n<details><summary>Show Answer<\/summary>paleontology\r\n\r\n<\/details><\/div>\r\n","rendered":"<h2>Describe biology as a science and identify the key components of scientific inquiry<\/h2>\n<p>The scope of biology is vast. Biologists may study anything from the microscopic (Figure 1a)\u00a0or submicroscopic view of a cell to ecosystems (Figure 1b) and the whole living planet.<\/p>\n<div id=\"attachment_1120\" style=\"width: 1086px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-1120\" class=\"wp-image-1120 size-full\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/3116\/2018\/03\/20190355\/figure01_01.jpg\" alt=\"Photo A depicts round colonies of blue-green algae. Each algae cell is about 5 microns across. Photo B depicts round fossil structures called stromatalites along a watery shoreline.\" width=\"1076\" height=\"432\" \/><\/p>\n<p id=\"caption-attachment-1120\" class=\"wp-caption-text\">Figure 1. (a) Formerly called blue-green algae, these cyanobacteria, shown here at 300\u00d7 magnification under a light microscope, are some of Earth&#8217;s oldest life forms. (b) These stromatolites along the shores of Lake Thetis in Western Australia are ancient structures formed by the layering of cyanobacteria in shallow waters.<\/p>\n<\/div>\n<p>Listening to the daily news, you will quickly realize how many aspects of biology are discussed every day. You may hear about <em>E.\u00a0coli\u00a0(Escherichia coli)\u00a0<\/em>outbreaks in spinach or\u00a0listeria\u00a0contamination in ice cream. Or you may hear about\u00a0efforts toward finding a cure for Ebola, Alzheimer&#8217;s disease, and cancer. On a global scale, many researchers are committed to finding ways to protect the planet, solve environmental issues, and reduce the effects of climate change. All of these diverse endeavors are related to different facets of the discipline of biology.<\/p>\n<p>Regardless of their particular focus of study, all\u00a0biologists\u00a0use the same methodology as they seek new discoveries: scientific inquiry.<\/p>\n<div class=\"textbox learning-objectives\">\n<h3>Learning Objectives<\/h3>\n<ul>\n<li>Identify the main branches of biology<\/li>\n<li>Describe &#8220;scientific inquiry&#8221; and identify its scope of coverage<\/li>\n<li>Form a hypothesis and use it to design a scientific experiment<\/li>\n<li>Analyze simple data and graphed results<\/li>\n<\/ul>\n<\/div>\n<h2>\u00a0The Branches of Biology<\/h2>\n<p>The scope of biology is broad and therefore contains many branches and sub-disciplines. Biologists may pursue one of those sub-disciplines and work in a more focused field. For instance, molecular biology and biochemistry study biological processes at the molecular and chemical level, including interactions among molecules such as DNA, RNA, and proteins, as well as the way they are regulated. Microbiology, the study of microorganisms, is the study of the structure and function of single-celled organisms. It is quite a broad branch itself, and depending on the subject of study, there are also microbial physiologists, ecologists, and geneticists, among others.<\/p>\n<div class=\"textbox key-takeaways\">\n<h3>Forensic\u00a0Science<\/h3>\n<div id=\"attachment_1828\" style=\"width: 310px\" class=\"wp-caption alignright\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-1828\" class=\"wp-image-1828 size-medium\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/110\/2016\/05\/03213712\/Figure_01_02_191-300x209.jpg\" alt=\"A scientist working in the lab.\" width=\"300\" height=\"209\" \/><\/p>\n<p id=\"caption-attachment-1828\" class=\"wp-caption-text\">Figure 2. This forensic scientist works in a DNA extraction room at the U.S. Army Criminal Investigation Laboratory at Fort Gillem, GA. (credit: United States Army CID Command Public Affairs)<\/p>\n<\/div>\n<p>Forensic science is the application of science to answer questions related to the law. Biologists as well as chemists and biochemists can be forensic scientists. Forensic scientists provide scientific evidence for use in courts, and their job involves examining trace materials associated with crimes. Interest in forensic science has increased in the last few years, possibly because of popular television shows that feature forensic scientists on the job. Also, the development of molecular techniques and the establishment of DNA databases have expanded the types of work that forensic scientists can do.<\/p>\n<p>Their job activities are primarily related to crimes against people such as murder, rape, and assault. Their work involves analyzing samples such as hair, blood, and other body fluids and also processing DNA (Figure 2) found in many different environments and materials.<\/p>\n<p>Forensic scientists also analyze other biological evidence left at crime scenes, such as insect larvae or pollen grains. Students who want to pursue careers in forensic science will most likely be required to take chemistry and biology courses as well as some intensive math courses.<\/p>\n<\/div>\n<p>Another field of biological study, neurobiology, studies the biology of the nervous system, and although it is considered a branch of biology, it is also recognized as an interdisciplinary field of study known as neuroscience. Because of its interdisciplinary nature, this sub-discipline studies different functions of the nervous system using molecular, cellular, developmental, medical, and computational approaches.<\/p>\n<div id=\"attachment_1519\" style=\"width: 360px\" class=\"wp-caption alignright\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-1519\" class=\"wp-image-1519\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/3116\/2018\/03\/20190401\/Figure_01_02_18.jpg\" alt=\"People sitting in the dirt with digging tools.\" width=\"350\" height=\"269\" \/><\/p>\n<p id=\"caption-attachment-1519\" class=\"wp-caption-text\">Figure 3. Researchers work on excavating dinosaur fossils at a site in Castell\u00f3n, Spain. (credit: Mario Modesto)<\/p>\n<\/div>\n<p>Paleontology, another branch of biology, uses fossils to study life&#8217;s history (Figure 3). Zoology and botany are the study of animals and plants, respectively. Biologists can also specialize as biotechnologists, ecologists, or physiologists, to name just a few areas. This is just a small sample of the many fields that biologists can pursue.<\/p>\n<p>Biology is the culmination of the achievements of the natural sciences from their inception to today. Excitingly, it is the cradle of emerging sciences, such as the biology of brain activity, genetic engineering of custom organisms, and the biology of evolution that uses the laboratory tools of molecular biology to retrace the earliest stages of life on earth. A scan of news headlines\u2014whether reporting on immunizations, a newly discovered species, sports doping, or a genetically modified food\u2014demonstrates the way biology is active in and important to our everyday world.<\/p>\n<h2>Scientific Inquiry<\/h2>\n<p>Science deals with testable knowledge about physical phenomena in the universe. The goal of science is to understand how the universe works. Biology focuses on understanding living things. To gain knowledge about nature and physical phenomena, scientists use a particular approach called \u201cscientific inquiry.\u201d<\/p>\n<p>Scientific inquiry is the best approach we have to understanding the natural world and predicting natural phenomena. Evidence for this claim can be found in the successes of science-based technologies. Take medicine, for example. Prior to the 1700s, most medical practices were based on folk traditions or on ideas promoted by religious leaders. Some of these prescientific remedies worked, but the process for discovering new treatments was a slow and haphazard system of trial and error. Ineffective treatments were often accepted simply because there was no clear procedure for evaluating them. Today, with science-based medicine and public health practices, we have gained unprecedented control over threats to our health. According to the Centers for Disease Control, the average life expectancy in the United States has increased by more than 30 years since 1900.<\/p>\n<p>Scientific inquiry has not displaced faith, intuition, and dreams. These traditions and ways of knowing have emotional value and provide moral guidance to many people. But hunches, feelings, deep convictions, old traditions, or dreams cannot be accepted directly as scientifically valid. Instead, science limits itself to ideas that can be tested through verifiable observations. Supernatural claims that events are caused by ghosts, devils, God, or other spiritual entities cannot be tested in this way.<\/p>\n<div class=\"textbox exercises\">\n<h3>Practice Question<\/h3>\n<p>Your friend sees this image of a circle of mushrooms and excitedly tells you it was caused by fairies dancing in a circle on the grass the night before. Can your friend\u2019s explanation be studied using the process of science?<\/p>\n<div style=\"width: 360px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/3116\/2018\/03\/20190405\/mushrooms.png\" alt=\"There are several mushrooms growing together in the pattern of a circular ring\" width=\"350\" height=\"262\" \/><\/p>\n<p class=\"wp-caption-text\">Figure 4. A fairy ring<\/p>\n<\/div>\n<div class=\"qa-wrapper\" style=\"display: block\"><span class=\"show-answer collapsed\" style=\"cursor: pointer\" data-target=\"q665464\"><strong>Show Answer<\/strong><\/span><\/p>\n<div id=\"q665464\" class=\"hidden-answer\" style=\"display: none\">In theory, you might try to observe the fairies. But fairies are magical or supernatural beings. We have never observed them using any verifiable method, so scientists agree that they cannot be studied using scientific tools. Instead, science has an explanation supported by strong evidence: \u201cfairy rings\u201d result when a single colony of fungus spreads out into good habitat over a period of many years. The core area is clear of mushrooms because the soil nutrients have been partly depleted there. This idea can be evaluated with repeated observations over time using chemical soil tests and other verifiable measurements.<\/div>\n<\/div>\n<\/div>\n<h2>Experiments and Hypotheses<\/h2>\n<p>Now we&#8217;ll\u00a0focus on the methods of scientific inquiry. Science often involves making\u00a0observations and developing hypotheses. Experiments and further observations are often used to test the hypotheses.<\/p>\n<p>A scientific experiment is a carefully organized procedure in which the scientist intervenes in a system to change something, then observes the result of the change. Scientific inquiry often involves doing experiments, though not always. For example, a scientist studying the mating behaviors of ladybugs might begin with detailed observations of ladybugs mating in their natural habitats. While this research may not be experimental, it is scientific: it involves careful and verifiable observation of the natural world. The same scientist might then treat some of the ladybugs with a hormone hypothesized to trigger mating and observe whether these ladybugs mated sooner or more often than untreated ones. This would qualify as an experiment because the scientist is now making a change in the system and observing the effects.<\/p>\n<h3>Forming a Hypothesis<\/h3>\n<p>When conducting scientific experiments, researchers develop hypotheses to guide experimental design. A\u00a0hypothesis is a suggested explanation that is both testable and falsifiable. You must be able to test your hypothesis, and it must be possible to prove your hypothesis true or false.<\/p>\n<p>For example, Michael\u00a0observes that maple trees lose their leaves in the fall. He might then propose a possible explanation for this observation: \u201ccold weather causes maple trees to lose their leaves in the fall.\u201d This statement is testable. He\u00a0could grow maple trees in a warm enclosed environment such as a greenhouse and see if their leaves still dropped in the fall. The hypothesis is also falsifiable. If the leaves still dropped in the warm environment, then clearly temperature was not the main factor in causing maple leaves to drop in autumn.<\/p>\n<p>In the Try It\u00a0below, you can practice recognizing scientific hypotheses. As you consider each statement, try to think as a scientist would: can I test this hypothesis with observations or experiments? Is the statement falsifiable? If the answer to either of these questions is \u201cno,\u201d the statement is not a valid scientific hypothesis.<\/p>\n<div class=\"textbox exercises\">\n<h3>Practice Questions<\/h3>\n<p>Determine whether each following statement is a scientific hypothesis.<\/p>\n<p>Air pollution from automobile exhaust can trigger symptoms in people with asthma.<\/p>\n<ol style=\"list-style-type: lower-alpha;\">\n<li>No. This statement is not testable or falsifiable.<\/li>\n<li>No. This statement is not testable.<\/li>\n<li>No. This statement is not falsifiable.<\/li>\n<li>Yes. This statement is testable and falsifiable.<\/li>\n<\/ol>\n<div class=\"qa-wrapper\" style=\"display: block\"><span class=\"show-answer collapsed\" style=\"cursor: pointer\" data-target=\"q429550\"><strong>Show Answer<\/strong><\/span><\/p>\n<div id=\"q429550\" class=\"hidden-answer\" style=\"display: none\">d: Yes. This statement is testable and falsifiable. This could be tested with a number of different kinds of observations and experiments, and it is possible to gather evidence that indicates that air pollution is not linked with asthma.<\/p>\n<\/div>\n<\/div>\n<p>Natural disasters, such as tornadoes, are punishments for bad thoughts and behaviors.<\/p>\n<ol style=\"list-style-type: lower-alpha;\">\n<li>No. This statement is not testable or falsifiable.<\/li>\n<li>No. This statement is not testable.<\/li>\n<li>No. This statement is not falsifiable.<\/li>\n<li>Yes. This statement is testable and falsifiable.<\/li>\n<\/ol>\n<div class=\"qa-wrapper\" style=\"display: block\"><span class=\"show-answer collapsed\" style=\"cursor: pointer\" data-target=\"q74245\">Show Answer<\/span><\/p>\n<div id=\"q74245\" class=\"hidden-answer\" style=\"display: none\">\n<p>a: No. This statement is not testable or falsifiable. \u201cBad thoughts and behaviors\u201d are excessively vague and subjective variables that would be impossible to measure or agree upon in a reliable way. The statement might be \u201cfalsifiable\u201d if you came up with a counterexample: a &#8220;wicked&#8221; place that was not punished by a natural disaster. But some would question whether the people in that place were really wicked, and others would continue to predict that a natural disaster was bound to strike that place at some point. There is no reason to suspect that people&#8217;s immoral behavior affects the weather unless you bring up the intervention of a supernatural being, making this idea even harder to test.<\/p>\n<\/div>\n<\/div>\n<\/div>\n<h3>Testing a Vaccine<\/h3>\n<p>Let&#8217;s\u00a0examine the scientific process by discussing an actual scientific experiment conducted by researchers at the University of Washington. These researchers investigated whether a vaccine may reduce the incidence of the human papillomavirus (HPV). The experimental process and results were published in an article titled, &#8220;<a href=\"http:\/\/www.ncbi.nlm.nih.gov\/pubmed\/12444178\" target=\"_blank\" rel=\"noopener\">A controlled trial of a human papillomavirus type 16 vaccine<\/a>.&#8221;<\/p>\n<p>Preliminary observations made by the researchers who conducted the HPV experiment are listed below:<\/p>\n<ul>\n<li>Human papillomavirus (HPV) is the most common sexually transmitted virus in the United States.<\/li>\n<li>There are about 40 different types of HPV. A significant number of people that have HPV are unaware of it because many of these viruses cause no symptoms.<\/li>\n<li>Some types of HPV can cause cervical cancer.<\/li>\n<li>About 4,000 women a year die of cervical cancer in the United States.<\/li>\n<\/ul>\n<div class=\"textbox exercises\">\n<h3>Practice Question<\/h3>\n<p>Researchers have developed a potential vaccine against HPV and want to test it.\u00a0What is the first testable hypothesis that the researchers should study?<\/p>\n<ol style=\"list-style-type: lower-alpha;\">\n<li>HPV causes cervical cancer.<\/li>\n<li>People should not have unprotected sex with many partners.<\/li>\n<li>People who get the vaccine will not get HPV.<\/li>\n<li>The HPV vaccine will protect people against cancer.<\/li>\n<\/ol>\n<div class=\"qa-wrapper\" style=\"display: block\"><span class=\"show-answer collapsed\" style=\"cursor: pointer\" data-target=\"q20917\"><strong>Show Answer<\/strong><\/span><\/p>\n<div id=\"q20917\" class=\"hidden-answer\" style=\"display: none\">Hypothesis A is not the best choice because this information is already known from previous studies. Hypothesis B\u00a0is not testable because scientific hypotheses are not value statements; they do not include judgments like \u201cshould,\u201d\u00a0\u201cbetter than,\u201d etc. Scientific evidence certainly might support this value judgment, but a hypothesis\u00a0would take a different form: \u201cHaving unprotected sex with many partners increases a person\u2019s risk for\u00a0cervical cancer.\u201d Before the researchers can test if the vaccine protects against cancer (hypothesis D), they want to test if it\u00a0protects against the virus. This statement will make an excellent hypothesis for the next study. The researchers should first test hypothesis C\u2014whether or not the new vaccine can prevent HPV.<\/div>\n<\/div>\n<\/div>\n<h3>Experimental Design<\/h3>\n<p>You\u2019ve successfully identified a hypothesis for the University of Washington\u2019s study on HPV: People who get the HPV vaccine will not get HPV.<\/p>\n<p>The next step is to design an experiment that will test this hypothesis. There are several important factors to consider when designing a scientific experiment. First, scientific experiments must have an experimental group. This is the group that receives the experimental treatment necessary to address the hypothesis.<\/p>\n<p>The experimental group receives the vaccine, but how can we know if the vaccine made a difference? Many things may change HPV infection rates in a group of people over time. To clearly show that the vaccine was effective in helping the experimental group, we need to include in our study an otherwise similar control group that does not get the treatment. We can then compare the two groups and determine if the vaccine made a difference. The control group shows us what happens in the absence of the factor under study.<\/p>\n<p>However, the control group cannot get \u201cnothing.\u201d Instead, the control group often receives a placebo. A <em>placebo<\/em> is a procedure that has no expected therapeutic effect\u2014such as giving a person a sugar pill or a shot containing only plain saline solution with no drug. Scientific studies have shown that the \u201cplacebo effect\u201d can alter experimental results because when individuals are told that they are or are not being treated, this knowledge can alter their actions or their emotions, which can then alter the results of the experiment.<\/p>\n<p>Moreover, if the doctor knows which group a patient is in, this can also influence the results of the experiment. Without saying so directly, the doctor may show\u2014through body language or other subtle cues\u2014his or her views about whether the patient is likely to get well. These errors can then alter the patient\u2019s experience and change the results of the experiment. Therefore, many clinical studies are \u201cdouble blind.\u201d In these studies, neither the doctor nor the patient knows which group the patient is in until all experimental results have been collected.<\/p>\n<p>Both placebo treatments and double-blind procedures are designed to prevent bias. Bias is any systematic error that makes a particular experimental outcome more or less likely. Errors can happen in any experiment: people make mistakes in measurement, instruments fail, computer glitches can alter data. But most such errors are random and don\u2019t favor one outcome over another. Patients\u2019 belief in a treatment can make it more likely to appear to \u201cwork.\u201d Placebos and double-blind procedures are used to level the playing field so that both groups of study subjects are treated equally and share similar beliefs about their treatment.<\/p>\n<div class=\"textbox exercises\">\n<h3>Practice Questions<\/h3>\n<p>The scientists who are researching the effectiveness of the HPV vaccine will test their hypothesis by separating 2,392 young women into two groups: the control group and the experimental group. Answer the following questions about these two groups.<\/p>\n<ol>\n<li>Which of the following groups most likely represents the control group?\n<ol style=\"list-style-type: lower-alpha;\">\n<li>This group is given a placebo.<\/li>\n<li>This group is deliberately infected with HPV.<\/li>\n<li>This group is given nothing.<\/li>\n<li>This group is given the HPV vaccine.<\/li>\n<\/ol>\n<\/li>\n<li>Which of the following groups most likely represents the experimental group?\n<ol style=\"list-style-type: lower-alpha;\">\n<li>This group is given a placebo.<\/li>\n<li>This group is deliberately infected with HPV.<\/li>\n<li>This group is given nothing.<\/li>\n<li>This group is given the HPV vaccine.<\/li>\n<\/ol>\n<\/li>\n<\/ol>\n<div class=\"qa-wrapper\" style=\"display: block\"><span class=\"show-answer collapsed\" style=\"cursor: pointer\" data-target=\"q918962\"><strong>Show Answers<\/strong><\/span><\/p>\n<div id=\"q918962\" class=\"hidden-answer\" style=\"display: none\">\n<ol>\n<li>a: This group is given a placebo.\u00a0A placebo will be a shot, just like the HPV vaccine, but it will have no active ingredient. It may\u00a0change peoples\u2019 thinking or behavior to have such a shot given to them, but it will not stimulate the\u00a0immune systems of the subjects in the same way as predicted for the vaccine itself.<\/li>\n<li>d: This group is given the HPV vaccine.\u00a0The experimental group will receive the HPV vaccine and researchers will then be able to\u00a0see if it works, when compared to the control group.<\/li>\n<\/ol>\n<\/div>\n<\/div>\n<\/div>\n<h3>Experimental Variables<\/h3>\n<p>A variable is a characteristic of a subject (in this case, of a person in the study) that can vary over time or among individuals. Sometimes a variable takes the form of a category, such as male or female; often a variable can be measured precisely, such as body height. Ideally, only one variable is different between the control group and the experimental group in a scientific experiment. Otherwise, the researchers will not be able to determine which variable caused any differences seen in the results. For example, imagine that the people in the control group were, on average, much more sexually active than the people in the experimental group. If, at the end of the experiment, the control group had a higher rate of HPV infection, could you confidently determine why? Maybe the experimental subjects were protected by the vaccine, but maybe they were protected by their low level of sexual contact.<\/p>\n<p>To avoid this situation, experimenters make sure that their subject groups are as similar as possible in all variables except for the variable that is being tested in the experiment. This variable, or factor, will be deliberately changed in the experimental group. The one variable that is different between the two groups is called the independent variable. An independent variable is known or hypothesized to cause some outcome. Imagine an educational researcher investigating the effectiveness of a new teaching strategy in a classroom. The experimental group receives the new teaching strategy, while the control group receives the traditional strategy. It is the teaching strategy that is the independent variable in this scenario. In an experiment, the independent variable is the variable that the scientist deliberately changes or imposes on the subjects.<\/p>\n<p>Dependent variables are known or hypothesized consequences; they are the effects that result from changes or differences in an independent variable. In an experiment, the dependent variables are those that the scientist measures before, during, and particularly at the end of the experiment to see if they have changed as expected. The dependent variable must be stated so that it is clear how it will be observed or measured. Rather than comparing \u201clearning\u201d among students (which is a vague and difficult to measure concept), an educational researcher might choose to compare test scores, which are very specific and easy to measure.<\/p>\n<p>In any real-world example, many, many variables MIGHT affect the outcome of an experiment, yet only one or a few independent variables can be tested. Other variables must be kept as similar as possible between the study groups and are called <em>control variables<\/em>. For our educational research example, if the control group consisted only of people between the ages of 18 and 20 and the experimental group contained people between the ages of 30 and 35, we would not know if it was the teaching strategy or the students&#8217; ages that played a larger role in the results. To avoid this problem, a good study will be set up so that each group contains students with a similar age profile. In a well-designed educational research study, student age will be a controlled variable, along with other possibly important factors like gender, past educational achievement, and pre-existing knowledge of the subject area.<\/p>\n<div class=\"textbox exercises\">\n<h3>Practice Questions<\/h3>\n<p>What is the independent variable in this experiment?<\/p>\n<ol style=\"list-style-type: lower-alpha;\">\n<li>Sex (all of the subjects will be female)<\/li>\n<li>Presence or absence of the HPV vaccine<\/li>\n<li>Age<\/li>\n<li>Presence or absence of HPV (the virus)<\/li>\n<\/ol>\n<div class=\"qa-wrapper\" style=\"display: block\"><span class=\"show-answer collapsed\" style=\"cursor: pointer\" data-target=\"q68680\">Show Answer<\/span><\/p>\n<div id=\"q68680\" class=\"hidden-answer\" style=\"display: none\">Answer b. Presence or absence of the HPV vaccine. This is the variable that is different between the control and the experimental groups.\u00a0All the subjects in this study are female, so this variable is the same in all groups.\u00a0In a well-designed study, the two groups will be of similar age.\u00a0The presence or absence of the virus is what the researchers will measure at the <em>end<\/em>\u00a0of the experiment. Ideally the two\u00a0groups will both be HPV-free at the start of the experiment.<\/p>\n<\/div>\n<\/div>\n<p>List three control variables other than age.<\/p>\n<p><textarea aria-label=\"Your Answer\" rows=\"3\"><\/textarea><\/p>\n<div class=\"qa-wrapper\" style=\"display: block\"><span class=\"show-answer collapsed\" style=\"cursor: pointer\" data-target=\"q903121\">Show Answer<\/span><\/p>\n<div id=\"q903121\" class=\"hidden-answer\" style=\"display: none\">Some possible control variables would be: general health of the women, sexual activity, lifestyle, diet,\u00a0socioeconomic status, etc.<\/p>\n<\/div>\n<\/div>\n<p>What is the dependent variable in this experiment?<\/p>\n<ol style=\"list-style-type: lower-alpha;\">\n<li>Sex (male or female)<\/li>\n<li>Rates of HPV infection<\/li>\n<li>Age (years)<\/li>\n<\/ol>\n<div class=\"qa-wrapper\" style=\"display: block\"><span class=\"show-answer collapsed\" style=\"cursor: pointer\" data-target=\"q907103\">Show Answer<\/span><\/p>\n<div id=\"q907103\" class=\"hidden-answer\" style=\"display: none\">Answer b. Rates of HPV infection. The researchers will measure how many individuals got infected with HPV after a given\u00a0period of time.<\/div>\n<\/div>\n<\/div>\n<h2>Interpreting Results<\/h2>\n<h3>Gathering Data<\/h3>\n<p>After the experiment is completed, the data gathered are carefully interpreted. This involves the measurement of the dependent variable. In the case of our HPV experiment, remember, the dependent variable is the rate of HPV infection.<\/p>\n<div class=\"textbox exercises\">\n<h3>Practice Question<\/h3>\n<p>The researchers found that, of the 1,200 women in the control group, nine were infected with HPV at the end of the study. Of the 1,200 women in the experimental group, zero were infected with HPV. Does this result support the original hypothesis, that the HPV vaccine would reduce HPV infection?<\/p>\n<p><textarea aria-label=\"Your Answer\" rows=\"2\"><\/textarea><\/p>\n<div class=\"qa-wrapper\" style=\"display: block\"><span class=\"show-answer collapsed\" style=\"cursor: pointer\" data-target=\"q318356\"><strong>Show Answer<\/strong><\/span><\/p>\n<div id=\"q318356\" class=\"hidden-answer\" style=\"display: none\">The results demonstrate that fewer individuals who got the vaccine were infected with HPV when compared to the number of infected individuals who did not get the vaccine. This supports the hypothesis that the new vaccine protects against HPV.<\/div>\n<\/div>\n<\/div>\n<h3>Significance<\/h3>\n<p>Although the HPV study suggests that the vaccine protects against infection by HPV, is the finding significant? In science, as in life, things can happen for many different reasons. A convincing study will rule out \u201cluck\u201d (random chance) as an explanation for the results. Strong results are said to be significant: very unlikely to occur by chance or random events.<\/p>\n<p>Whether the outcome is significant often depends on the size of study; the larger the number of individuals enrolled, the more convincing the results are likely to be. For example, imagine only 10 women were enrolled in the study. In the control group, 2 in 5 of the women became infected. In the experimental group, 0 in 5 were infected. At first you might think this proves the vaccine\u2019s effectiveness, but it is NOT a convincing or significant result. Why not? Random events could easily explain the difference between the groups. For example, perhaps none of the five women in the experimental group were sexually active over the study period. They therefore stood no chance of acquiring HPV. The vaccine might appear to work, but a skeptical reader could account for the results by proposing many other scenarios.<\/p>\n<p>However, imagine if the same study were done with 10,000 women, and the infection rates were 2,000 of 5,000 in the control group and zero of 5,000 in the experimental group. Random events would be spread out among a very large group of people in this study; on average, the two big groups should have similar sexual behavior and other factors influencing infection rates. If there is a big difference at the end of the study, it is very unlikely that <em class=\"italic\">this<\/em> result occurred by random chance.<\/p>\n<p>Statistical analyses did support the significance of the HPV vaccine result.<\/p>\n<div class=\"textbox exercises\">\n<h3>Practice Question<\/h3>\n<p>Researchers reported significant results from the HPV vaccine experiment. If the results had NOT\u00a0been significant, what would this mean?<\/p>\n<p><textarea aria-label=\"Your Answer\" rows=\"2\"><\/textarea><\/p>\n<div class=\"qa-wrapper\" style=\"display: block\"><span class=\"show-answer collapsed\" style=\"cursor: pointer\" data-target=\"q185159\"><strong>Show Answer<\/strong><\/span><\/p>\n<div id=\"q185159\" class=\"hidden-answer\" style=\"display: none\">If the results from this experiment were not significant, it would mean that the number of women who did\u00a0not get HPV after being vaccinated was the same number that would be seen just from random chance.<\/div>\n<\/div>\n<\/div>\n<p>After the results are interpreted and conclusions are drawn, researchers often return to their work and begin asking further questions. In this way, scientific inquiry is a powerful tool for exploration.<\/p>\n<div class=\"textbox exercises\">\n<h3>Practice Question<\/h3>\n<p>What would be a good next question the HPV vaccine researchers may want to test? (<i>More than one answer is correct.<\/i>)<\/p>\n<ol style=\"list-style-type: lower-alpha;\">\n<li>At what age is this vaccine most effective (what age group should be vaccinated)?<\/li>\n<li>Does the HPV vaccine protect males as well as females?<\/li>\n<li>Does protecting against HPV protect against cancer?<\/li>\n<li>Should young girls be forced to get the vaccine against their parents&#8217; wishes?<\/li>\n<\/ol>\n<div class=\"qa-wrapper\" style=\"display: block\"><span class=\"show-answer collapsed\" style=\"cursor: pointer\" data-target=\"q689643\"><strong>Show Answers<\/strong><\/span><\/p>\n<div id=\"q689643\" class=\"hidden-answer\" style=\"display: none\">\n<p>Questions a, b, anc c are the best questions. These questions are currently being studied.<\/p>\n<p>Although question d\u00a0is important and\u00a0has generated a lot of political heat, it is not a\u00a0scientific question. Scientists can predict what will happen if girls are or are not vaccinated, but cannot\u00a0decide whether disease risk or parental authority is more important.<\/p>\n<\/div>\n<\/div>\n<\/div>\n<h3>Graphing Data<\/h3>\n<p>Watch this ten-minute video about simple graphing:<\/p>\n<p><iframe loading=\"lazy\" id=\"oembed-1\" title=\"A Beginner&#39;s Guide to Graphing Data\" width=\"500\" height=\"281\" src=\"https:\/\/www.youtube.com\/embed\/9BkbYeTC6Mo?feature=oembed&#38;rel=0\" frameborder=\"0\" allowfullscreen=\"allowfullscreen\"><\/iframe><\/p>\n<div class=\"textbox exercises\">\n<h3>Check Your Understanding<\/h3>\n<p>What discipline of biology is focused on life\u2019s history?<\/p>\n<ul>\n<li>paleontology<\/li>\n<li>forensic botany<\/li>\n<li>neurobiology<\/li>\n<\/ul>\n<details>\n<summary>Show Answer<\/summary>\n<p>paleontology<\/p>\n<\/details>\n<\/div>\n\n\t\t\t <section class=\"citations-section\" role=\"contentinfo\">\n\t\t\t <h3>Candela Citations<\/h3>\n\t\t\t\t\t <div>\n\t\t\t\t\t\t <div id=\"citation-list-6018\">\n\t\t\t\t\t\t\t <div class=\"licensing\"><div class=\"license-attribution-dropdown-subheading\">CC licensed content, Original<\/div><ul class=\"citation-list\"><li>Revision, adaptation, and original content. <strong>Authored by<\/strong>: Shelli Carter and Lumen Learning. <strong>Provided by<\/strong>: Lumen Learning. <strong>License<\/strong>: <em><a target=\"_blank\" rel=\"license\" href=\"https:\/\/creativecommons.org\/licenses\/by\/4.0\/\">CC BY: Attribution<\/a><\/em><\/li><\/ul><div class=\"license-attribution-dropdown-subheading\">CC licensed content, Shared previously<\/div><ul class=\"citation-list\"><li>Biology. <strong>Provided by<\/strong>: OpenStax CNX. <strong>Located at<\/strong>: <a target=\"_blank\" href=\"http:\/\/cnx.org\/contents\/185cbf87-c72e-48f5-b51e-f14f21b5eabd@10.8\">http:\/\/cnx.org\/contents\/185cbf87-c72e-48f5-b51e-f14f21b5eabd@10.8<\/a>. <strong>License<\/strong>: <em><a target=\"_blank\" rel=\"license\" href=\"https:\/\/creativecommons.org\/licenses\/by\/4.0\/\">CC BY: Attribution<\/a><\/em>. <strong>License Terms<\/strong>: Download for free at http:\/\/cnx.org\/contents\/185cbf87-c72e-48f5-b51e-f14f21b5eabd@10.8<\/li><li>Stromatolites at Lake Thetis. <strong>Authored by<\/strong>: Ruth Ellison. <strong>Located at<\/strong>: <a target=\"_blank\" href=\"https:\/\/flic.kr\/p\/ezabK\">https:\/\/flic.kr\/p\/ezabK<\/a>. <strong>License<\/strong>: <em><a target=\"_blank\" rel=\"license\" href=\"https:\/\/creativecommons.org\/licenses\/by-nc\/4.0\/\">CC BY-NC: Attribution-NonCommercial<\/a><\/em><\/li><li>Scientific Inquiry. <strong>Provided by<\/strong>: Open Learning Initiative. <strong>Located at<\/strong>: <a target=\"_blank\" href=\"https:\/\/oli.cmu.edu\/jcourse\/workbook\/activity\/page?context=434a5c2680020ca6017c03488572e0f8\">https:\/\/oli.cmu.edu\/jcourse\/workbook\/activity\/page?context=434a5c2680020ca6017c03488572e0f8<\/a>. <strong>Project<\/strong>: Introduction to Biology (Open + Free). <strong>License<\/strong>: <em><a target=\"_blank\" rel=\"license\" href=\"https:\/\/creativecommons.org\/licenses\/by-nc-sa\/4.0\/\">CC BY-NC-SA: Attribution-NonCommercial-ShareAlike<\/a><\/em><\/li><\/ul><div class=\"license-attribution-dropdown-subheading\">All rights reserved content<\/div><ul class=\"citation-list\"><li>A Beginner&#039;s Guide to Graphing Data. <strong>Authored by<\/strong>: Bozeman Science. <strong>Located at<\/strong>: <a target=\"_blank\" href=\"https:\/\/youtu.be\/9BkbYeTC6Mo\">https:\/\/youtu.be\/9BkbYeTC6Mo<\/a>. <strong>License<\/strong>: <em>All Rights Reserved<\/em>. <strong>License Terms<\/strong>: Standard YouTube License<\/li><\/ul><div class=\"license-attribution-dropdown-subheading\">Public domain content<\/div><ul class=\"citation-list\"><li>Modification of Cyanobacteria; scale-bar data from Matt Russell. <strong>Provided by<\/strong>: NASA. <strong>Located at<\/strong>: <a target=\"_blank\" href=\"https:\/\/commons.wikimedia.org\/wiki\/File:Cyanobacteria_guerrero_negro.jpg\">https:\/\/commons.wikimedia.org\/wiki\/File:Cyanobacteria_guerrero_negro.jpg<\/a>. <strong>License<\/strong>: <em><a target=\"_blank\" rel=\"license\" href=\"https:\/\/creativecommons.org\/about\/pdm\">Public Domain: No Known Copyright<\/a><\/em><\/li><\/ul><\/div>\n\t\t\t\t\t\t <\/div>\n\t\t\t\t\t <\/div>\n\t\t\t <\/section>","protected":false},"author":18,"menu_order":1,"template":"","meta":{"_candela_citation":"[{\"type\":\"cc\",\"description\":\"Biology\",\"author\":\"\",\"organization\":\"OpenStax CNX\",\"url\":\"http:\/\/cnx.org\/contents\/185cbf87-c72e-48f5-b51e-f14f21b5eabd@10.8\",\"project\":\"\",\"license\":\"cc-by\",\"license_terms\":\"Download for free at http:\/\/cnx.org\/contents\/185cbf87-c72e-48f5-b51e-f14f21b5eabd@10.8\"},{\"type\":\"original\",\"description\":\"Revision, adaptation, and original content\",\"author\":\"Shelli Carter and Lumen Learning\",\"organization\":\"Lumen Learning\",\"url\":\"\",\"project\":\"\",\"license\":\"cc-by\",\"license_terms\":\"\"},{\"type\":\"pd\",\"description\":\"Modification of Cyanobacteria; 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