Science 103 Life Sciences Bilgen Bilgin 2008 Fall Lecture 1 SCIE 103 Life Sciences

Why study science? Scientific literacy can be defined as the knowledge and understanding of scientific concepts and processes required for scientific decision making, participation in civic and cultural affairs, and economic productivity. The tenets of scientific literacy include the ability to: Find or determine answers to questions derived from everyday experiences. Describe, explain, and predict natural phenomena. Understand articles about science. Engage in non-technical conversation about the validity of conclusions. Identify scientific issues underlying national and local decisions. Pose explanations based on evidence derived from one's own work. 2008 Fall Lecture 1 SCIE 103 Life Sciences

Why study science? It is its predictive power that distinguishes a scientific from a nonscientific explanation, even if the prediction does not match the experimental outcome. To make a prediction, scientists follow hypothetico-deductive reasoning: If “such and such” is correct, and we do “this and that,” the following will happen. Then they perform the experiment, compare the results with the prediction, and decide whether the explanation should be revised. 2008 Fall Lecture 1 SCIE 103 Life Sciences

Scientific Method Scientific method involves a number of basic principles that one should systematically proceed with. These principles should be applied in an orderly manner with the appropriate technique, helping to ascertain an answer to a question. Scientific method is a process that allows new knowledge of natural or physical or social phenomena to be acquired, gaining explanations by sifting the truth from the false, rather than by guesswork or by something supernatural or from beyond the bounds of nature. It is this method of discovery, and the justification for that discovery, which must be accomplished entirely with integrity. The first discipline is to observe. One dictum of the word science is that the truth is ascertained by observation, and observation is something that has obviously stirred human thought processes since early beginnings. The word science comes from the Latin scienta, derived from scire which means “to know”, and was coined in Roman times. Ancient tablets from around 2000BC show that scholars from the Babylonian civilisation had knowledge of a theory that the ancient Greek mathematician Pythagoras would not fully establish until the Fifth Century BC. The oldest written records precede all of these and were excavated from ancient Mesopotamian sites, the oldest of which date back to 7000BC. They include astronomical, medical and chemical observations, as well as mathematical tables. In fact, evidence of trying to organise knowledge can be traced back to prehistoric times in the form of records carved in bone or stone, and by paintings on cave walls. 2008 Fall Lecture 1 SCIE 103 Life Sciences

Scientific Method Once observed, questions must be asked and then a hypothesis, (from the Greek hupothesis meaning “proposal”), can be formulated in order for a prediction or predictions to be derived. These would then be tested by means of experiment. The results would need to be analysed and evaluated. If the end product supports the original prediction and one’s curiosity satisfied, then a theory can be established. If the test results are not consistent with the original hypothesis, then alterations to the said hypothesis need to be applied and a fresh set of results achieved. The theory, (from the Greek theoria meaning “speculation”), can be accepted if the results obtained are repeatable and cannot be made false. 2008 Fall Lecture 1 SCIE 103 Life Sciences

Scientific Method The logical approach to considering a matter from every point of view is a science in itself. It was an Ancient Greek philosopher and scientist, Aristotle, who founded the science we know as Logic, this is another word derived from the Greek language. Logos translates to ‘word’,’ speech’ or ‘reason’. Aristotle lived from 384-322BC and was to become the most prominent pupil at the Greek philosopher Plato’s Academy in Athens. Plato lived from 427-347BC and was himself a great thinker of his time. He was the first to use the term philosophy, derived from two Greek words; ‘philos’ meaning loving and ‘sophia’, wisdom. Hence philosopher for one who is a student of philosophy, a “lover of wisdom”. Plato had been a student of Socrates (c.469-399BC), whose works were passed on in Plato’s dialectical writings. The dialectic method is how Socrates had argued that truthful knowledge comes from conversation and methodical questioning. A system of philosophical thinking that centuries later would form a basis for some areas of political thinking. Plato adapted these ideas and he essentially based his beliefs upon the theory of “forms”, or ideal substance, which set out that in an ideal world only perfect forms can be the objects of true knowledge. Plato’s philosophy did not accept that scientific experiment could establish any facts, because the mind is the primary principle over matter. Aristotle was in agreement with these theories for a time but later became critical of Plato, arguing that all things are subject to change and therefore they are not all a pure form. 2008 Fall Lecture 1 SCIE 103 Life Sciences

Scientific Method Aristotle had joined the Academy at the tender age of seventeen and remained there for about twenty years. He then left to become the tutor of Alexander the Great, returning to Athens to found the Lyceum, another great ancient school. Apart from logic, he was a prolific writer of a vast number of works on a wide range of subjects; working and writing on zoology, astronomy, ethics, aesthetics, politics, psychology and physics. His first great works, though, were the writings on logic. Collectively they became known as the “Organon” (meaning “instrument” or “tool”), because they were perceived to provide the required procedure to gain understanding in a philosophical way. In such a way Aristotle laid down many of the rules for scientific method Aristotle maintained that our knowledge only comes from our sensory experiences. He regarded logic as the careful study of methods of understanding or intelligence being the same for any subject matter. He developed deductive reasoning to back this up. This is where a pair or more of statements give a new conclusion when taken together. The most famous example of this being: “All human beings are mortal” and “All Greeks are human beings” giving the logical conclusion that “All Greeks are mortal”. The formal answer from the argument became known as a “syllogism” (The Greek "sullogismos" means "deduction"). The opposite to deduction is induction where the assumption is that if something is true in a number of observed instances, it must be true in similar, but unobserved instances. The inductive method provides the scope for scientific method to employ the use of statistical procedures in order to redefine existing concepts. The simplest form of induction is employed in the field of modern politics, with the probabilities of an election being predicted by an opinion poll. Here a small section of the electorate would be questioned in order to project a result across the total population. 2008 Fall Lecture 1 SCIE 103 Life Sciences

Scientific Method The legacy of Aristotle’s philosophy has been to influence all areas of science, even up to the present day. His doctrines have played important roles in theology, education, politics and zoology. During the Middle Ages, Aristotle’s philosophy became the foundation of Islamic philosophy, also then being incorporated into Christian religious science. His works were adopted by Arabic and Jewish scholars alike, in order to reconcile belief and reason for faith. In the field of education, modern teaching methods in science are partly based on Aristotle’s theories. In political science, his writings “Politics” foretold the future efforts of many scholars regarding the discipline of government. The use of scientific method attempts to eliminate the thoughts and influence of a scientist upon an experiment. The scientist may really have a preference for the result and therefore bias the conclusion and subsequent theory. A fundamental error would be to not experiment at all and mistake the hypothesis of an observation as the theory. An example of this comes from Aristotle himself, with his theory that Greek men had more teeth than Greek women. He argued vehemently that this was so, but never experimented the hypothesis. The testing of an hypothesis is paramount to scientific method, indeed to scientific progress. In physics this is the supreme discipline. The theory must stand up to repeated testing. However, continual testing of an original theory, as new technology comes in to use and new observations are made, leads to its own new hypotheses and theories. An original theory may not be tested completely to its end, but years later the work can be seen as an important step in the right direction. 2008 Fall Lecture 1 SCIE 103 Life Sciences

Scientific Method One such science that proves this point is astronomy. Heliocentric vs Geocentric Universe Aristarchus (310 BC - ca. 230 BC) was a Greek astronomer and mathematician, born on the island of Samos, in Greece. He was the first person to present an explicit argument for a heliocentric model of the solar system, placing the Sun, not the Earth, at the center of the known universe (hence he is sometimes known as the "Greek Copernicus"). He was influenced by the Pythagorean Philolaus of Kroton, but in contrast to Philolaus he had both identified the central fire with the Sun, as well as putting other planets in correct order from the Sun. His astronomical ideas were rejected in favor of the geocentric theories of Aristotle and Ptolemy until they were successfully revived nearly 1800 years later by Copernicus and extensively developed and built upon by Johannes Kepler and Isaac Newton. A Polish scientist called Nicolaus Copernicus (1473-1543) worked for thirty years on a hypothesis he derived from observing that the heavenly bodies were in different positions in the night sky. He argued that it was the rotation and orbital motion of the Earth around the Sun that was responsible for this effect, throwing the perceived ideas of European culture into shock, and defying Christian church doctrines. In the year of his death he published his greatest work “On the Revolutions of the Heavenly Spheres”. Copernicus’s model to back this up could not be proved right as it contained flaws. But future astronomers built on this beginning. Copernicus’s theory of the Sun being the centre of the Universe was proved by the Italian Galileo Galilei (1564-1642). He developed the telescope and saw that the planet Venus went through phases, changing its aspect. The plausibility of this was confirmed with his work on the acceleration of a body or object. He found that whatever weight the body was, heavy or light, the rate of acceleration was the same, and more importantly, that the body neither sped up or slowed down on a perfectly smooth surface. This was an important step in founding modern scientific method. Whereas, before Galileo, observations on phenomena were casually made, he methodically made those observations amenable to testing. Making them prone to experimentation in order to arrive at a theory. 2008 Fall Lecture 1 SCIE 103 Life Sciences

Ptolematic Universe 2008 Fall Lecture 1 SCIE 103 Life Sciences

Copernican Universe 2008 Fall Lecture 1 SCIE 103 Life Sciences

Tycho & Kepler Universes 2008 Fall Lecture 1 SCIE 103 Life Sciences

Scientific Method In 1687 the English scientist and mathematician, Sir Isaac Newton (1642-1727), published a scientific masterpiece, Principia. Newton’s mathematical genius helped him “see” more deeply into the secrets of nature than ever before. Building on the work of Galileo, the book laid down Newton’s Laws of Motion. Unless acted upon by an unbalanced force, a body at rest stays at rest, and a moving body continues at the same speed in the same straight line. An unbalanced force applied to a body gives it acceleration proportional to the force and in the direction of the force. When a body A exerts a force on body B, B exerts an equal and opposite force on A; that is, to every action there is an equal and opposite reaction. 2008 Fall Lecture 1 SCIE 103 Life Sciences

Scientific Method Perhaps Newton’s greatest contribution to science was the development of his general theory of gravitation as a universal law of attraction between two bodies. Legend has it that, whilst sitting under an apple tree, he witnessed an apple fall to the ground. This dedication to observation inspired him to investigate the phenomenon. His activeness in mathematical theory, using classical techniques along with analytical probability; (deduction and induction), meant that he could answer so many problems that others before him could not primarily do so. Newton was then able to link the resulting law of gravity with observations from Danish scientist Tycho Brahe (1546-1601), along with predictions by his German assistant Johann Kepler (1571-1630), proving their theories about the motion of the planets. This linking of ideas is a role model of scientific method. 2008 Fall Lecture 1 SCIE 103 Life Sciences

Scientific Method The great advantage of the scientific method is that it is “unprejudiced” if the rules are adhered to. Errors can occur, either intrinsically by the failure of equipment, or by the increasing error in recording or measuring. However, in science there are standard ways of estimating and thus reducing errors. One does not have to believe the findings of the researcher, one can make the experiment and therefore determine for oneself whether the truth is there or not. This is the fundamental difference between science and art, and even science and an act of faith. Aristotle had supreme confidence in the ability of all human beings’ ability to deduce an understanding of the world around them. For every individual, science acquires systematic knowledge of the truth and laws of natural or physical phenomena that govern the world. Science classifies by definite rules. To be “scientific” is to agree with, and be well instructed in the principles of science. The manner of proceeding to an end, by orderly means, is “method”. The appearance that the use of scientific method is simply logical can be misleading, there is no more complex question of how we arrive at our thoughts. 2008 Fall Lecture 1 SCIE 103 Life Sciences

The Hypothetico-Deductive Method Francis Bacon (1561-1626), a 17th century English philosopher, was the first individual to suggest a universal methodology for science. Bacon believed that scientific method required an inductive process of inquiry. Philosopher Karl Popper suggested that it is impossible to prove a scientific theory true by means of induction, because no amount of evidence assures us that contrary evidence will not be found. Instead, Karl Popper proposed that proper science is accomplished by deduction. Deduction involves the process of falsification. Falsification is a particular specialized aspect of hypothesis testing. It involves stating some output from theory in specific and then finding contrary cases using experiments or observations. The methodology proposed by Popper is commonly known as the hypothetico-deductive method. Popper's version of scientific method first begins with the postulation of a hypothesis. A hypothesis is an educated guess or a theory that explains some phenomenon. The researcher then tries to prove or test this scientific theory false through prediction or experimentation. A prediction is a forecast or extrapolation from the current state of the system of interest. Predictions are most useful if they can go beyond simple forecast. An experiment is a controlled investigation designed to evaluate the outcomes of causal manipulations on some system of interest. 2008 Fall Lecture 1 SCIE 103 Life Sciences

Relationship between phenomena, theory, and understanding using scientific method. The broadest, most inclusive goal of science is to understand. Understanding encompasses a number of other goals of science, many of which are quite specialized. Explanation is perhaps the most important basic goal of understanding. Explanation consists of relating observed reality to a system of concepts, laws, or empirically based generalizations. Explanation may also relate observed phenomena to a system of causes, or link them to mechanisms that are hierarchically structured at lower-levels of function. 2008 Fall Lecture 1 SCIE 103 Life Sciences

Relationship between phenomena, theory, and understanding using scientific method. The secondary goal of explanation has two important components: generalization and unification. Generalization may be considered to be the condensation of a body of empirical fact into a simple statement. In the process of such condensation, it is likely that some detail must be omitted and the processes and phenomenon abstracted. Generalization may also involve isolating the phenomenon from other aspects of the system of interest. This is sometimes referred to as idealization. A second aspect of explanation is the unification of apparently unrelated phenomena in the same abstract or ideal system of concepts. Another minor goal of science is the validation of constructed models (conceptual model building) of understanding. Validation is accomplished through hypothesis testing, prediction, and falsification. 2008 Fall Lecture 1 SCIE 103 Life Sciences

Overview of the Scientific Method The scientific method is a process for experimentation that is used to explore observations and answer questions. Scientists use the scientific method to search for cause and effect relationships in nature. In other words, they design an experiment so that changes to one item cause something else to vary in a predictable way. 2008 Fall Lecture 1 SCIE 103 Life Sciences

Steps of the Scientific Method Ask a Question: The scientific method starts when you ask a question about something that you observe: How, What, When, Who, Which, Why, or Where? And, in order for the scientific method to answer the question it must be about something that you can measure, preferably with a number. 2008 Fall Lecture 1 SCIE 103 Life Sciences

Steps of the Scientific Method Do Background Research: Rather than starting from scratch in putting together a plan for answering your question, you want to be a savvy scientist using library and Internet research to help you find the best way to do things and insure that you don't repeat mistakes from the past. 2008 Fall Lecture 1 SCIE 103 Life Sciences

Steps of the Scientific Method Construct a Hypothesis: A hypothesis is an educated guess about how things work: "If _____[I do this] _____, then _____[this]_____ will happen." You must state your hypothesis in a way that you can easily measure, and of course, your hypothesis should be constructed in a way to help you answer your original question. 2008 Fall Lecture 1 SCIE 103 Life Sciences

Steps of the Scientific Method Test Your Hypothesis by Doing an Experiment: Your experiment tests whether your hypothesis is true or false. It is important for your experiment to be a fair test. You conduct a fair test by making sure that you change only one factor at a time while keeping all other conditions the same. You should also repeat your experiments several times to make sure that the first results weren't just an accident. 2008 Fall Lecture 1 SCIE 103 Life Sciences

Steps of the Scientific Method Analyze Your Data and Draw a Conclusion: Once your experiment is complete, you collect your measurements and analyze them to see if your hypothesis is true or false. Scientists often find that their hypothesis was false, and in such cases they will construct a new hypothesis starting the entire process of the scientific method over again. Even if they find that their hypothesis was true, they may want to test it again in a new way. 2008 Fall Lecture 1 SCIE 103 Life Sciences

Steps of the Scientific Method Communicate Your Results: Scientists publish their final report in a scientific journal or by presenting their results on a poster at a scientific meeting. 2008 Fall Lecture 1 SCIE 103 Life Sciences

Steps of the Scientific Method Even though we show the scientific method as a series of steps, keep in mind that new information or thinking might cause a scientist to back up and repeat steps at any point during the process. A process like the scientific method that involves such backing up and repeating is called an iterative process. https://www.gc.maricopa.edu/biology/glacier/scientific_method/ http://sunshine.chpc.utah.edu/labs/scientific_method/sci_method_main.html http://biology.clc.uc.edu/courses/bio104/sci_meth.htm 2008 Fall Lecture 1 SCIE 103 Life Sciences

What is Ockham's Razor? When a new set of facts requires the creation of a new theory the process is far from the orderly picture often presented in books. Many hypothesis are proposed, studied, rejected. Researchers discuss their validity (sometimes quite heatedly) proposing experiments which will determine the validity of one or the other, exposing flaws in their least favorite ones, etc. Yet, even when the unfit hypotheses are discarded, several options may remain, in some cases making the exact same predictions, but having very different underlying assumptions. In order to choose among these possible theories a very useful tool is what is called Ockham's razor. Ockham's Razor is the principle proposed by William of Ockham in the fourteenth century: “Pluralitas non est ponenda sine neccesitate”, which translates as “entities should not be multiplied unnecessarily”. 2008 Fall Lecture 1 SCIE 103 Life Sciences

Summary Question: The scientist raises a question about what (s)he sees going on. The question raised must have a “simple”, concrete answer that can be obtained by performing an experiment. Hypothesis: a testable‚ tentative answer to a question   (hypo = under‚ beneath; thesis = an arranging) Inductive reasoning goes from a set of specific observations to general conclusions: I observed cells in x, y, and z organisms, therefore all animals have cells. Deductive reasoning flows from general to specific. From general premises, a scientist would extrapolate to specific results: if all organisms have cells and humans are organisms, then humans should have cells. This is a prediction about a specific case based on the general premises. Generally, in the scientific method, if a particular hypothesis/premise is true and “X” experiment is done, then one should expect (prediction) a certain result. This involves the use of “if-then” logic. For example, if my hypothesis that my throat is sore because I did too much screaming at the ball game is true and if a doctor examines my vocal cords, then (s)he should be able to observe that they are inflamed, and as the inflammation heals, the sore throat should go away. A prediction is the expected results if the hypothesis and other underlying assumptions and principles are true and an experiment is done to test that hypothesis. For example, in physics if Newton’s Theory of Motion is true and certain “unexplained” measurements and calculations pointing to the possibility of another planet are correct, then if I point my telescope to the specific position that I can calculate mathematically, I should be able to discover/observe that new planet. Indeed, that is the way in which Neptune was discovered in 1846. Testing: Then, the scientist performs the experiment to see if the predicted results are obtained. If the expected results are obtained, that supports (but does not prove) the hypothesis. In science when testing, when doing the experiment, it must be a controlled experiment. The scientist must contrast an “experimental group” with a “control group”. The two groups are treated EXACTLY alike except for the ONE variable being tested. Sometimes several experimental groups may be used. For example, in an experiment to test the effects of day length on plant flowering, one could compare normal, natural day length (the control group) to several variations (the experimental groups). 2008 Fall Lecture 1 SCIE 103 Life Sciences

Definitions of terms related to the scientific method: Laws are generalizations, principles or patterns in nature and theories are the explanations of those generalizations. Theory : a hypothesis that has been expand and is supported by a great deal of experimental data. Examples:  Cell Theory; Theory of Relativity Hypothesis: an educated guess (the best estimate) as to a causal relationship between two variables. Example from Cricket Experiment:  Air temperature determines the rate of chirping in crickets Experimental variables: the two factors or conditions that will vary or change in the course of an experiment Examples from Cricket experiment:  (1) Air temperature and (2) rate of chirping Independent Variable:  the factor or condition that YOU DELIBERATELY VARY in the experiment Example from Cricket experiment:   air temperature - you selected four or five different air temperatures to use Dependent Variable:  the factor or condition that YOU MEASURE as the results of the experiment. Example from Cricket experiment: rate of chirping - you counted the number of chirps per minute at the different temperatures Controlled variable or controlled factors: All the other conditions that are kept constant in the experiment, that you want not to vary Examples from Cricket experiment:  humidity, wind speed, number of crickets, etc Experimental Control:   The experimental control is one group or set up in the experiment which is totally lacking the independent variable.  This control provides a baseline against which to compare your experimental findings.  It tells you how your experiment will turn out when there is NO level of the independent variable present. Problem:  in biological experiments it is sometimes difficult to provide an experimental control. In the cricket experiment the factor that determined the rate of chirping was air temperature, so air temperature is the independent variable for the experiment. The experimental control, then, would be crickets exposed to NO air temperature. Is that possible?????  No, so the best we can do is use the normal temperature in the field as a control and experimentally vary the temperature above and below that. Predictions: Results you expect to obtain in an experiment if your hypothesis is correct. Examples from Cricket experiment:  If air temperature determines the rate of chirping in crickets then when you raise the air temperature from 5o C to 50o C the number of chirps per minute should increase. 2008 Fall Lecture 1 SCIE 103 Life Sciences