01 - Introduction and The Scientific Method(1).pptx

Chapter 1 Learning About Human Biology Cecie Starr | Beverly McMillan © Cengage Learning 2016  My Objective I want you to understand the biology...

Chapter 1 Learning About Human Biology Cecie Starr | Beverly McMillan © Cengage Learning 2016  My Objective I want you to understand the biology of your body such that you can: – Have constructive conversations with doctors, family, etc. – Make informed decisions about your health © Cengage Learning 2016  Approaching This Course Biology has a lot of vocabulary – Anatomy: the study of the physical parts of the body – Physiology: the study of the functions of those parts and interactions between them. It can feel dry and daunting – Flash cards – Concept maps © Cengage Learning 2016  Shared Features of Life Basic characteristics of living things – Consist of one or more cells – Take in and use energy and materials (metabolism) – Sense and respond to changes in the environment – Maintain homeostasis – Reproduce and grow © Cengage Learning 2016 © Cengage Learning 2016 Figure 1.1 p  Response to Stimuli © Cengage Learning 2016  Living Things Reproduce © Cengage Learning 2016 © Cengage Learning 2016  Our Place in the Natural World Humans have evolved over time – Evolution means change over time Biological organisms evolve by changes in DNA Organisms classified into groups with similar characteristics – Humans are primates – Humans are also mammals and vertebrates © Cengage Learning 2016  MAMMALS 4,500 living species VERTEBRATES including more than 50,000 species of fishes, amphibians, reptiles, birds, and mammals Protis Plant Fun Anima ts s gi ls Bacter Archa Eukar ia ea ya © Cengage Learning 2016 Figure 1.3 p  Distinctive Human Characteristics Humans are related to every other life form Humans share characteristics with some of these life forms – Body hair – Manual dexterity – Complex brain – Apes: closest primate relatives © Cengage Learning 2016 © Cengage Learning 2016 Figure 1.4 p3  Life’s Organization We can approach biology from different levels of organization: – Atoms: smallest units of matter – Molecules: combinations of atoms – Macromolecules: larger, complex molecules like carbohydrates, fats, proteins, and DNA – Cells: built from molecules – Tissues: Groups of cells working together – Organs: made up of different kinds of tissues – Organ systems make up entire organisms © Cengage Learning 2016  A atom B molecule C cell D tissue E organ F organ system (muscle cells) (heart muscle) (heart) (cardiovascular system) (A, B, C, F: © Cengage Learning; D: Ed Reschke/Peter Arnold; E: CMSP/Custom Medical Stock) © Cengage Learning 2016  K the biosphere G organism H population I community J ecosystem (human) G: © Lavaria Ferreri Liotti/Shutterstock.com; H: © Rafael Ramirez Lee/Shutterstock.com; I: © Robert J. Beyers II/Shutterstock.com; J: © Sebastien Burel/Shutterstock.com; K: NASA © Cengage Learning 2016  Flow of Energy and Materials Organisms must take in energy and materials Energy flows into the biosphere from the sun – Solar energy used by plants to create chemical “fuel” – Fuel used for building tissues – Other raw materials come from air, soil, and water One-way flow of energy through organisms and cycling of materials among them connects each to the others – Where do humans fit in? © Cengage Learning 2016  Sun © Cengage Learning 2016 A fungus Decomposer Producers Grasses and other plants Consumers Cattle and humans Clockwise from top left: Edward S. Ross; © iStockphoto.com/shaunl; Nancy J. Pierce/Science Source; © Ozerov Alexander/Shutterstock.com  Using Science to Explain Natural Events Scientific studies – Systematic – Gather information by doing experiments Or record detailed observations © Cengage Learning 2016  The Scientific Method Steps in the scientific method – Observe some natural phenomenon – Identify a question or problem to explore – Develop a testable hypothesis – Make a specific prediction – Test the prediction Note: This is the ideal process – Science is often a lot of "messing around" and making observations – The finalized experiment from which conclusions are drawn should be a controlled experiment © Cengage Learning 2016  Hypothesis Eating a high-protein breakfast reduces daily appetite. Prediction Young women who eat a high-protein breakfast will eat less later in the day than when they eat a “normal- protein” breakfast or none at all. Experiment Control Group Experimental Group Skips breakfast Eats 1 week of “normal- protein” breakfasts and 1 week of high-protein breakfasts Blood tests and brain scans for all groups Results Strong desire to eat Reduced desire to eat, at lunch and especially after protein- throughthe evening, rich breakfast; less including late-night unhealthy snacking snacking Questionnaires closely track results of physiological tests (hormones in blood and brain scans). Conclusion Eating a breakfast containing 35 grams of protein improved appetite control in the test group of young “breakfast-skipping” women. © Evikka/Shutterstock.com © Y_L/Shutterstock.com © Cengage Learning 2016  Scientific Experiments Test carried out under controlled conditions Variable – Factor that can change with time or different circumstances Researchers design experiments to test one variable at a time Control group – Used to compare results against tested group © Cengage Learning 2016  Experimental Process Control group should be identical to the experimental group – Except for the variable being studied Eliminate unwanted variables – Critical in obtaining reliable results Sampling error – Occurs when results from a tested subset of a group is not representative of group as a whole – Most likely to occur with small sample sizes Note: sometimes, especially with living things, it can be hard to control all possible variables. – Large sample size helps to overcome this – Larger population = less likelihood of sampling error © Cengage Learning 2016  Experimental Conclusions Must be consistent with experimental findings Example from breakfast study – Incorrect conclusion: eating a high-protein breakfast helps people lose weight  Weight loss was not specifically measured – Correct conclusion: eating breakfast, especially one high in protein, helps curb desire to eat more later in the day © Cengage Learning 2016  Sometimes Science is about Putting Pants on Frogs… This example illustrates the "messing around" part of science To draw valid conclusions, Spallanzani would have: – Designed a more controlled experiment – Had a large sample size – Repeated testing multiple times. © Cengage Learning 2016  Critical Thinking in Science and Life Critical thinking – Evaluate information objectively © Cengage Learning 2016  Steps in Critical Thinking Evaluate the source of information – Credible scientific evidence is better than opinions and hearsay – Question credentials and motives Evaluate the content of information – Differentiate between cause of an event and correlation with an event Spurious Correlations – Differentiate between fact and opinion © Cengage Learning 2016  Critical Thinking Activity Take a moment to think about this graph. Talk with a partner if you’d like. Teacher’s note: I’m not taking a political side. Just evaluate the information. Thoughts? Questions? Concerns? © Cengage Learning 2016  Science in Perspective Scientific theory – Explains a large number of observations – Based on repeated, careful testing of hypotheses – Usually only becomes accepted after years of testing by multiple scientists © Cengage Learning 2016 © Cengage Learning 2016  Changing Theories Theories can be modified or rejected – When scientific test results do not align – When new data or evidence is collected Example – Some facts in this textbook will be revised one day as scientists learn more Willingness to reconsider ideas – Major strength of science © Cengage Learning 2016  Limits of Science Science cannot explain: – The meaning of life – Why each of us dies at a certain moment Subjective answers shaped by experiences and beliefs Science does not involve value judgments – May lead to situations where research is at odds with moral or ethical standards © Cengage Learning 2016 © Cengage Learning 2016  The Human Body Multicellular Follows hierarchy of organization – Cells, tissues, organs, organ systems, organism Responds to stimuli (signals from the environment) – both internal and external Obtains energy via metabolism Eleven interconnected systems – Work together to maintain homeostasis © Cengage Learning 2016  Internal vs. External Internal organs are housed within two major body cavities – Dorsal cavity – Ventral cavity To be considered "inside" the body, a substance must cross a membrane barrier – Ex: Digestive tract – indigestible items can be swallowed and come out intact – Respiratory and Urinary systems are also "exposed" to the outside Part of maintaining homeostasis is regulating what enters and what leaves © Cengage Learning 2016  Homeostasis Cells make up State of chemical body systems and physical “stability” muscle cells – Dynamic equilibrium (constantly changing) – Can never stay exactly stable Failure to maintain Stable conditions allow cells to survive homeostasis = death muscular system Body system functions to help © Cengage Learning 2016 maintain homeostasis  Negative Feedback © Cengage Learning 2016  Negative Feedback Most systems of the body use negative feedback – Work against a change in a specific variable Three main parts – Sensor or receptor: senses change in variable – Control center: "decides" what to do based on the information received – Effector: Takes an action to (hopefully) correct the change © Cengage Learning 2016  Example: Body Temperature © Cengage Learning 2016  Example: Body Temperature Both sides of the loop are negative feedback Working to correct/counter a change in temperature © Cengage Learning 2016  Example: Blood Sugar Glucose: simple sugar, key "fuel" of cells – Your "blood sugar" refers to glucose molecules in your blood As organs do more work, they do more metabolism – Need more glucose Glucose reserves are stored in the pancreas Two main hormones (chemical signals, part of the endocrine system) control glucose levels – Insulin tells cells to take glucose out of the blood – Glucagon signals the pancreas to release more glucose © Cengage Learning 2016  Example: Blood Sugar © Cengage Learning 2016  Example: Blood Sugar © Cengage Learning 2016  Homeostatic Breakdown: Diabetes Problems with insulin molecule Type 1: Cannot produce insulin – Genetic – BUT: cells will still respond to insulin – Insulin shots give individuals the insulin they cannot make Type 2: Cells stop responding to insulin – Can only control glucose through lifestyle – Regulate how much sugar enters via diet – Glucose is used through activity/exercise © Cengage Learning 2016  Homeostatic Breakdown: Diabetes © Cengage Learning 2016  Positive Feedback Works with the change in a variable – Amplifies the change – "Let's hurry up and get this done" Only three examples in the human body: – Childbirth – Blood clotting – Menstrual cycle  Some argument that this is negative feedback due to it being a cycle  Homeostasis = maintaining a 28 day cycle © Cengage Learning 2016  Childbirth Will continue until the initiating stimulus (pressure on the cervix) is removed © Cengage Learning 2016  Blood Clotting © Cengage Learning 2016  Systems of the Human Body © Cengage Learning 2016  The Structural Systems Integumentary – Skin and extensions (hair, nails) – Acts as a barrier to the environment (immune function) – Helps to regulate body temperature – Involved in synthesis of Vitamin D (which requires UV radiation) © Cengage Learning 2016  The Structural Systems Muscular – Muscles attached to bones – Provide for structure and movement with the skeletal system – Activity generates heat © Cengage Learning 2016  The Structural Systems Skeletal – Bones and attaching ligaments and tendons – Provide a rigid framework for the muscles – Storage of calcium – Stem cells in bone marrow produce new blood cells  Connection to cardiovascular system © Cengage Learning 2016  The Control Systems Nervous – Brain, spinal cord, nerves, and sensory organs – "Electrical" control of the body – Provide more immediate sensing of and response to stimuli – Control center for many feedback loops – Storage of long-term information (memories) – Many homeostatic set points are "hard wired" © Cengage Learning 2016  The Control Systems Endocrine – Glands of the body – Secrete hormones internally  Molecules that act as chemical signals – Not as immediate as nervous system  Can still be relatively fast (ex: glucose regulation over the course of 30-60 minutes)  Can be VERY long term (ex: changes of puberty across many years) – Not as coherent as other systems  Loosely connected in that most glands are controlled by the pituitary gland © Cengage Learning 2016  The Transport Systems Cardiovascular – Heart, arteries, veins, capillaries, and blood – Transports everything internally  Oxygen and CO2  Hormones  Glucose and other compounds from food  Waste products from cells © Cengage Learning 2016  The Transport Systems Lymphatic/Immune – Lymph nodes and lymphatic vessels – Fluid that leaks from the cardiovascular system – Contains many specialized white blood cells called lymphatic cells that filter leaked fluid © Cengage Learning 2016  The "Loading and Unloading" Systems Respiratory – Lungs and respiratory tract – Loads oxygen into blood – Unloads CO2 from blood – Assists in regulating pH © Cengage Learning 2016  The "Loading and Unloading" Systems Digestive – Mouth, esophagus, stomach, small and large intestines – Accessory organs: Salivary glands, pancreas, liver – Breaks down food and absorbs chemical components into blood © Cengage Learning 2016  The "Loading and Unloading" Systems Urinary – Kidneys, bladder, urethra – Removes waste products (urea) from the blood – Regulates water content of blood – Regulates pH of blood © Cengage Learning 2016  The Reproductive Systems Male – Testes, vas deferens, seminal vesicles, prostate, and penis – Creates sperm to transmit genetic material – Endocrine function of testes Female – Ovaries, fallopian tubes, uterus, vagina – Releases mature eggs for reproduction – Receives sperm – Nourishes developing embryo and eventually fetus – Variety of endocrine functions © Cengage Learning 2016  Interconnected Systems All systems play a role in homeostasis Human body incredibly complex Maintaining all variables at the same time requires feedback and contributions from all systems © Cengage Learning 2016