BIOL 1440 1st Edition Lecture 1 I II III Outline of Current Lecture Genius Scientific method and what each step means Atomic mass with protons and electrons Current Lecture Smallest unit of classification system is species Similar physical and functional characteristics Can interbreed and produce fertile offspring 2nd smallest unit is genus All living human beings belong to the same genus and species Homo sapiens Bipedalism able to stand upright and walk on two legs Opposable thumbs able to grasp objects between thumb and tips of fingers Large brain relative to body size Capacity for language both spoken and written Human Biology can be studied on many different levels of organization Atom Molecule Cell Tissue Organ Organ system Community Organism Ecosystem Biosphere Science Is Both a body of knowledge and a process Science is the study of the natural world Biology specifically studies living things Science is two things Knowledge about the natural world The process used to acquire knowledge Called the Scientific Method Steps in the Scientific Method Observe and generalize Formulate a hypothesis Make a testable prediction Experiment or observe Draw a conclusion Modify the hypothesis as necessary and repeat Make observations about the natural world Ask a question or make generalizations based on observations Every winter in the past was colder than the preceding summer Winter will always be colder than summer A hypothesis is a tentative statement about how things may work in the natural world A hypothesis must be testable and potentially able to be proven incorrect Should be based on the hypothesis Are often in the form of if then statements Used to test accuracy of the hypothesis An experiment should be designed to eliminate other possible explanations for the results For example set up two experimental groups that differ in only one variable A good experiment uses controls as a basis of comparison 5 The conclusion may be that the experimental data supports or fails to support the hypothesis We never say that the experiment proves the hypothesis Why not Because we may discover more data in future experiments or with more advanced technology that disproves the hypothesis Modify the hypothesis as necessary and repeat steps 3 through 5 If prediction is not supported the hypothesis must be modified If the prediction is supported only one small part of the hypothesis has been tested Further testing required Findings can be disseminated in Peer reviewed journals Experts must approve articles before publication Experiments are sometimes repeated or critiqued conclusions are debated Popular press Electronic publications Internet is less regulated than print and broadcast media For a hypothesis to become a Scientific Theory it must Be broad Be extensively tested Be supported over time Explain a broad range of facts Have a high degree of reliability Theories may be refuted in the future In this course learn to think like a scientist Be a skeptic Appreciate the value of statistics Learn to read graphics Distinguish anecdotes from scientific evidence Separate facts from conclusions Understand the differences between correlation and causation Role of Science in Society Science improves technology and the human condition Science has limits Science helps us to make informed choices Study guide questions List the 7 characteristics that all living things must have If something has some of the characteristics of living things but not all is it still a living thing Chapter 2 The Chemistry of Living Things All matter on Earth is made of Elements Cannot be broken down to a simpler form Iron gold potassium helium carbon H Hydrogen C Carbon Atoms Smallest functional unit of elements An atom is the smallest unit that has all an elements physical and chemical properties Consist of protons neutrons and electrons Protons Positive charge have mass Found in nucleus core of atom Neutrons No charge neutral have mass Also found in nucleus of atom Electrons Negative charge no mass Found orbiting atom s nucleus in shells Each element has a unique Atomic Number above the symbol Defined by the number of protons E g Hydrogen has 1 proton Phosphorus P has 15 protons Atomic Mass below the symbol Equal to number of protons neutrons In an electrically neutral atom number of protons number of electrons That is positive charges negative charges Isotopes have a different number of neutrons Same number of protons different of neutrons Isotopes are forms of an element with a different number of neutrons than the usual number Same atomic number same number of protons Different atomic mass different number of neutrons E g 3 forms of Hydrogen exist in nature Unstable isotopes are called radioisotopes Radioisotopes give off energy radiation Some are harmful to humans Used for determining age of fossils 14C Some are useful in medicine 6 atomic number Protons C 12 011 atomic mass Protons neutron