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Unformatted text preview: 7/16/2020 The Science of Biology | Boundless Biology Boundless Biology The Study of Life The Science of Biology 1/34 7/16/2020 The Science of Biology | Boundless Biology Introduction to the Study of Biology Biology is the study of life and living things through rigorously-tested and peer-reviewed scienti c research methods. LEARNING OBJECTIVES Describe the eld of biological science KEY TAKEAWAYS Key Points Biology has evolved as a eld of science since it was rst studied in ancient civilizations, although modern biology is a relatively recent eld. Science is a process that requires the testing of ideas using evidence gathered from the natural world. Science is iterative in nature and involves critical thinking, careful data collection, rigorous 2/34 7/16/2020 The Science of Biology | Boundless Biology peer review, and the communication of results. Science also refers to the body of knowledge produced by scienti c investigation. Pseudoscience is a belief presented as scienti c although it is not a product of scienti c investigation. Key Terms pseudoscience: Any belief purported to be scienti c or supported by science that is not a product of scienti c investigation. science: A process for learning about the natural world that tests ideas using evidence gathered from nature. Biology: A natural science concerned with the study of life and living organisms. The Study of Life Biology is a natural science concerned with the study of life and living organisms. Modern biology is a vast and eclectic eld composed of many specialized disciplines that study the structure, function, growth, distribution, evolution, or other features of living organisms. However, despite the broad scope of biology, there are 3/34 7/16/2020 The Science of Biology | Boundless Biology certain general and unifying concepts that govern all study and research: the cell is the basic unit of life genes (consisting of DNA or RNA) are the basic unit of heredity evolution accounts for the unity and diversity seen among living organisms all organisms survive by consuming and transforming energy all organisms maintain a stable internal environment 4/34 7/16/2020 The Science of Biology | Boundless Biology Biology: The Study of Life: A collection of organisms clockwise from top left: bacteria, koala, fern, toadstool, tree frog, tarantula. Biological research indicates the rst forms of life on Earth were microorganisms that existed for billions of years before the evolution of larger organisms. The mammals, birds, and owers so familiar to us are all relatively recent, originating within the last 200 million years. Modern-appearing humans, Homo sapiens, are a relatively new species, having inhabited this planet for only the last 200,000 years (approximately). Stromatolites: Stromatolites, sedimentary accretions formed by the actions of cyanobacteria, provide fossil evidence of life on Earth about 3.5 billion years ago. History of Biological Science Although modern biology is a relatively recent development, sciences related to and included within it 5/34 7/16/2020 The Science of Biology | Boundless Biology have been studied since ancient times. Natural philosophy was studied as early as the ancient civilizations of Mesopotamia, Egypt, the Indian subcontinent, and China. However, the origins of modern biology and its approach to the study of nature are most often traced back to ancient Greece. (Biology is derived from the Greek word “bio” meaning “life” and the su x “ology” meaning “study of.”) Advances in microscopy also had a profound impact on biological thinking. In the early 19th century, a number of biologists pointed to the central importance of the cell and in 1838, Schleiden and Schwann began promoting the now universal ideas of the cell theory. Jean-Baptiste Lamarck was the rst to present a coherent theory of evolution, although it was the British naturalist Charles Darwin who spread the theory of natural selection throughout the scienti c community. In 1953, the discovery of the double helical structure of DNA marked the transition to the era of molecular genetics. Science and Pseudoscience Science is a process for learning about the natural world. Most scienti c investigations involve the testing of potential answers to important research questions. For example, oncologists ( cancer doctors) are interested in nding out why some cancers respond well to chemotherapy while others are una ected. Based on their growing knowledge of molecular biology, some doctors suspect a connection between a patient’s 6/34 7/16/2020 The Science of Biology | Boundless Biology genetics and their response to chemotherapy. Many years of research have produced numerous scienti c papers documenting the evidence for a connection between cancer, genetics, and treatment response. Once published, scienti c information is available for anyone to read, learn from, or even question/dispute. This makes science an Phrenology: Dr. Spurzheim’s divisions of the organs of phrenology marked externally : Phrenology is a pseudoscience that attempted to determine brain function and personality by analyzing an individual’s skull. iterative, or cumulative, process, where previous research is used as the foundation for new research. Our current understanding of any issue in the sciences is the culmination of all previous work. Pseudoscience is a belief presented as scienti c although it is not a product of scienti c investigation. Pseudoscience is often known as fringe or alternative science. It usually lacks the carefully-controlled and thoughtfully-interpreted experiments which provide the foundation of the natural sciences and which contribute to their advancement. 7/34 7/16/2020 The Science of Biology | Boundless Biology Scienti c Reasoning Science is knowledge obtained from logical inferences and deductive experimentation that attempts to comprehend nature. LEARNING OBJECTIVES Compare and contrast theories and hypotheses KEY TAKEAWAYS Key Points A hypothesis is a statement/prediction that can be tested by experimentation. A theory is an explanation for a set of observations or phenomena that is supported by extensive research and that can be used as the basis for further research. Inductive reasoning draws on observations to infer logical conclusions based on the evidence. Deductive reasoning is hypothesis-based logical reasoning that deduces 8/34 7/16/2020 The Science of Biology | Boundless Biology conclusions from test results. Key Terms theory: a well-substantiated explanation of some aspect of the natural world based on knowledge that has been repeatedly con rmed through observation and experimentation hypothesis: a tentative conjecture explaining an observation, phenomenon, or scienti c problem that can be tested by further observation, investigation, and/or experimentation The Process of Science Science (from the Latin scientia, meaning “knowledge”) can be de ned as knowledge that covers general truths or the operation of general laws, especially when acquired and tested by the scienti c method. The steps of the scienti c method will be examined in detail later, but one of the most important aspects of this method is the testing of hypotheses (testable statements) by means of repeatable experiments. Although using the scienti c method is inherent to science, it is inadequate in determining what science is. This is because it is relatively easy to apply the scienti c method to disciplines such as physics and chemistry, but when it comes to disciplines like archaeology, paleoanthropology, psychology, and geology, the 9/34 7/16/2020 The Science of Biology | Boundless Biology scienti c method becomes less applicable as it becomes more di cult to repeat experiments. These areas of study are still sciences, however. Consider archaeology: even though one cannot perform repeatable experiments, hypotheses may still be supported. For instance, an archaeologist can hypothesize that an ancient culture existed based on nding a piece of pottery. Further hypotheses could be made about various characteristics of this culture. These hypotheses may be found to be plausible (supported by data) and tentatively accepted, or may be falsi ed and rejected altogether (due to contradictions from data and other ndings). A group of related hypotheses, that have not been disproven, may eventually lead to the development of a veri ed theory. A theory is a tested and con rmed explanation for observations or phenomena that is supported by a large body of evidence. Science may be better de ned as elds of study that attempt to comprehend the nature of the universe. Scienti c Reasoning One thing is common to all forms of science: an ultimate goal “to know.” Curiosity and inquiry are the driving forces for the development of science. Scientists seek to understand the world and the way it operates. To do this, they use two methods of logical thinking: inductive reasoning and deductive reasoning. 10/34 7/16/2020 The Science of Biology | Boundless Biology Inductive reasoning is a form of logical thinking that uses related observations to arrive at a general conclusion. This type of reasoning is common in descriptive science. A life scientist such as a biologist makes observations and records them. These data can be Scienti c Reasoning: Scientists use two types of reasoning, inductive and deductive, to advance scienti c knowledge. qualitative or quantitative and the raw data can be supplemented with drawings, pictures, photos, or videos. From many observations, the scientist can infer conclusions (inductions) based on evidence. Inductive reasoning involves formulating generalizations inferred from careful observation and the analysis of a large amount of data. Brain studies provide an example. In this type of research, many live brains are observed while people are doing a speci c activity, such as viewing images of food. The part of the brain that “lights up” during this activity is then predicted to be the part controlling the response to the selected stimulus; in this case, images of food. The “lighting up” of the various areas of the brain is caused by excess absorption of radioactive sugar derivatives by active areas of the brain. The resultant increase in radioactivity is observed by a scanner. Then researchers can stimulate that part of the brain to see if similar responses result. 11/34 7/16/2020 The Science of Biology | Boundless Biology Deductive reasoning or deduction is the type of logic used in hypothesis-based science. In deductive reason, the pattern of thinking moves in the opposite direction as compared to inductive reasoning. Deductive reasoning is a form of logical thinking that uses a general principle or law to forecast speci c results. From those general principles, a scientist can extrapolate and predict the speci c results that would be valid as long as the general principles are valid. Studies in climate change can illustrate this type of reasoning. For example, scientists may predict that if the climate becomes warmer in a particular region, then the distribution of plants and animals should change. These predictions have been written and tested, and many such predicted changes have been observed, such as the modi cation of arable areas for agriculture correlated with changes in the average temperatures. Both types of logical thinking are related to the two main pathways of scienti c study: descriptive science and hypothesis-based science. Descriptive (or discovery) science, which is usually inductive, aims to observe, explore, and discover, while hypothesis-based science, which is usually deductive, begins with a speci c question or problem and a potential answer or solution that can be tested. The boundary between these two forms of study is often blurred and most scienti c endeavors combine both approaches. The fuzzy boundary becomes apparent when thinking about how easily observation can lead to speci c questions. For 12/34 7/16/2020 The Science of Biology | Boundless Biology example, a gentleman in the 1940s observed that the burr seeds that stuck to his clothes and his dog’s fur had a tiny hook structure. Upon closer inspection, he discovered that the burrs’ gripping device was more reliable than a zipper. He eventually developed a company and produced the hook-and-loop fastener popularly known today as Velcro. Descriptive science and hypothesis-based science are in continuous dialogue. A Burr: This fruit attaches to animal fur via the hooks on its surface to improve distribution. Velcro is an example of a biomimetic invention which has copied burrs and uses small exible hooks to reversibly attach to u y surfaces. The Scienti c Method The scienti c method is a process by which 13/34 7/16/2020 The Science of Biology | Boundless Biology observations are questioned; hypotheses are created and tested; and the results are analyzed. LEARNING OBJECTIVES Discuss hypotheses and the components of a scienti c experiment as part of the scienti c method KEY TAKEAWAYS Key Points In the scienti c method, observations lead to questions that require answers. In the scienti c method, the hypothesis is a testable statement proposed to answer a question. In the scienti c method, experiments (often with controls and variables) are devised to test hypotheses. In the scienti c method, analysis of the results of an experiment will lead to the hypothesis being accepted or rejected. Key Terms 14/34 7/16/2020 The Science of Biology | Boundless Biology scienti c method: a way of discovering knowledge based on making falsi able predictions (hypotheses), testing them, and developing theories based on collected data hypothesis: an educated guess that usually is found in an “if…then…” format control group: a group that contains every feature of the experimental group except it is not given the manipulation that is hypothesized The Scienti c Method Biologists study the living world by posing questions about it and seeking science -based responses. This approach is common to other sciences as well and is often referred to as the scienti c method. The scienti c method was used even in ancient times, but it was rst documented by England’s Sir Francis Bacon (1561–1626) who set up inductive methods for scienti c inquiry. The scienti c method can be applied to almost all elds of study as a logical, rational, problem-solving method. The scienti c process typically starts with an observation (often a problem to be solved) that leads to a question. Let’s think about a simple problem that starts with an observation and apply the scienti c method to solve the problem. A teenager notices that his friend is 15/34 7/16/2020 The Science of Biology | Boundless Biology really tall and wonders why. So his question might be, “Why is my friend so tall? ” Proposing a Hypothesis Recall that a hypothesis is an educated guess that can be tested. Hypotheses often also include an explanation for the educated guess. To solve one problem, several hypotheses may be proposed. For example, the student Sir Francis Bacon: Sir Francis Bacon (1561–1626) is credited with being the rst to de ne the scienti c method. might believe that his friend is tall because he drinks a lot of milk. So his hypothesis might be “If a person drinks a lot of milk, then they will grow to be very tall because milk is good for your bones.” Generally, hypotheses have the format “If… then…” Keep in mind that there could be other responses to the question; therefore, other hypotheses may be proposed. A second hypothesis might be, “If a person has tall parents, then they will also be tall, because they have the genes to be tall. ” Once a hypothesis has been selected, the student can make a prediction. A prediction is similar to a hypothesis but it is truly a guess. For instance, they might predict 16/34 7/16/2020 The Science of Biology | Boundless Biology that their friend is tall because he drinks a lot of milk. Testing a Hypothesis A valid hypothesis must be testable. It should also be falsi able, meaning that it can be disproven by experimental results. Importantly, science does not claim to “prove” anything because The Scienti c Method: The scienti c method consists of a series of well-de ned steps. If a hypothesis is not supported by experimental data, a new hypothesis can be proposed. scienti c understandings are always subject to modi cation with further information. This step— openness to disproving ideas—is what distinguishes sciences from non-sciences. The presence of the supernatural, for instance, is neither testable nor falsi able. To test a hypothesis, a researcher will conduct one or more experiments designed to eliminate one or more of the hypotheses. Each experiment will have one or more variables and one or more controls. A variable is any part of the experiment that can vary or change during the experiment. The control group contains every feature of the experimental group except it is not given the manipulation that is hypothesized. For example, a control group could be a group of varied 17/34 7/16/2020 The Science of Biology | Boundless Biology teenagers that did not drink milk and they could be compared to the experimental group, a group of varied teenagers that did drink milk. Thus, if the results of the experimental group di er from the control group, the di erence must be due to the hypothesized manipulation rather than some outside factor. To test the rst hypothesis, the student would nd out if drinking milk a ects height. If drinking milk has no a ect on height, then there must be another reason for the height of the friend. To test the second hypothesis, the student could check whether or not his friend has tall parents. Each hypothesis should be tested by carrying out appropriate experiments. Be aware that rejecting one hypothesis does not determine whether or not the other hypotheses can be accepted. It simply eliminates one hypothesis that is not valid. Using the scienti c method, the hypotheses that are inconsistent with experimental data are rejected. While this “tallness” example is based on observational results, other hypotheses and experiments might have clearer controls. For instance, a student might attend class on Monday and realize she had di culty concentrating on the lecture. One hypothesis to explain this occurrence might be, “If I eat breakfast before class, then I am better able to pay attention.” The student could then design an experiment with a control to test this hypothesis. The scienti c method may seem too rigid and 18/34 7/16/2020 The Science of Biology | Boundless Biology structured. It is important to keep in mind that although scientists often follow this sequence, there is exibility. Many times, science does not operate in a linear fashion. Instead, scientists continually draw inferences and make generalizations, nding patterns as their research proceeds. Scienti c reasoning is more complex than the scienti c method alone suggests. Basic and Applied Science Basic science increases the knowledge base of a eld of research while applied science uses that knowledge to solve speci c problems. LEARNING OBJECTIVES Di erentiate between basic and applied science KEY TAKEAWAYS Key Points The only goal of basic science research is to increase the knowledge base of a particular eld of study. Applied science uses the knowledge base supplied by basic science to devise 19/34 7/16/2020 The Science of Biology | Boundless Biology solutions, often technological, to speci c problems. The basic science involved in mapping the human genome is leading to applied science techniques that will diagnose and treat genetic diseases. Key Terms basic science: research done solely to expand the knowledge base applied science: The discipline dealing with the art or science of applying scienti c knowledge to practical problems. Two Types of Science: Basic Science and Applied Science The scienti c community has been debating ...
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