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Intro to Biology Bio 9 CCSF Lecture Outline • Welcome & syllabus • Intro to Biology • The scientific method Biology is the study of life Biology has many subdisciplines • • • • • • • • • • Biochemistry Cell biology Ecology Physiology Microbiology Genetics Molecular biology Population genetics Botany Agriculture • • • • • • • • • • Bioinformatics Systems biology Health Medicine Pharmacology Evolution Anatomy Taxonomy Paleobiology Etc., etc., etc. Biology from a human perspective • Focuses on human body • Biological principles and their relevance to human health, human physiology, and the human experience • Environment, evolution, and other biology topics are also of significant human interest Biology is transforming our lives • As available biological information increases, our knowledge of biology advances Biology is transforming our lives • Antibiotics have saved countless lives • Antibiotics are part of a constant war against microbes • The war isn’t over yet Biology is transforming our lives • Oscar Pistorius, South Africa, 400m • Fastest time: 46.25 sec • World record: 43.18sec • Cleared to compete in the Olympics • Didn’t compete (3rd at S.A. Oly trials; but Oly standard = 45.55) Knowing Biology is a good way to get a job • Developments in biological knowledge have led to discovery of new drugs • Many drugs require special manufacturing procedures • The bay area is a pretty good place to get such a job Knowing biology is a good way to get a job • America has a rapidly aging population • Jobs in healthcare are rapidly increasing Knowing Biology is a good way to help out • Biology addresses many needs and dangers the earth and its inhabitants currently face Knowing biology is a good way to stay healthy through a long life Knowing Biology can help you make decisions about right and wrong Knowing Biology can help you avoid being deceived Knowing Biology can stop crime On a piece of paper • Write the following – Your name – Where you’re from – Guilty pleasure music – The goals you have for CCSF – How Bio 9 fits into those goals • Share with your tablemates when you are done Biology and other sciences owe their progress to the Scientific Method Hypothesis testing Experimental design Clinical trials There is no set “Scientific Method” • Jane Goodall did not conduct “experiments” • Neither did Charles Darwin • Experiments are still very important • Two basic forms of the scientific method: • Discovery Science • Hypothesis testing The scientific method Observations of interesting phenomena lead to a hypothesis (educated guess) as to their causes Predictions based on the hypothesis lead to experimental tests The scientific method When results are obtained according to predictions, the hypothesis is supported, and further predictions about the hypothesis can be made When results contradict hypothesis, the hypothesis is rejected, and the hypothesis must either be revised or discarded for a new one LE 1-8a-1 Hypothesis testing an important means by which science advances Observations Question LE 1-8a-1 A good hypothesis must be testable Observations Question Hypothesis #1: Dead batteries Hypothesis #2: Burnt-out bulb LE 1-8a-3 A good hypothesis must be falsifiable Observations Question Hypothesis #1: Dead batteries Prediction: Replacing batteries will fix problem Test prediction Hypothesis #2: Burnt-out bulb Prediction: Replacing bulb will fix problem Test prediction While good hypotheses are always falsifiable, proving them "true” can be very difficult Observations Question Hypothesis #1: Dead batteries Prediction: Replacing batteries will fix problem Test prediction Test falsifies hypothesis Hypothesis #2: Burnt-out bulb Prediction: Replacing bulb will fix problem Test prediction Test does not falsify hypothesis Scientists record data using SI (metric) units of measurement In what way(s) is the science of biology influencing and changing our culture? A) by providing new tools that can be used in forensics B) by revolutionizing medicine and agriculture C) by helping us evaluate environmental issues and the impacts of human actions D) all of the above E) none of the above Does excess iron decrease growth? • How can we test this? Does excess iron decrease growth? • How can we test this? • How many groups should we use? • What size are the groups? • How shall we create the groups? • What is the dependent/independent variable? Does excess iron decrease growth? • How can we test this? • How many groups should we use? • What size are the groups? • How shall we create the groups? • What is the dependent/independent variable? • How would this experiment be different if it were conducted with people? Good experiments are controlled • Controls are references which can be used for comparison • Experimental groupreceives treatment (independent variable) • Control group- does not receive treatment • Control variablesomething besides the independent variable which affects the outome Experimental terminology • Experimental group- group receiving treatment in question • Control group- group not receiving treatment • Independent variable- the treatment • Dependent variableexpected measurable result of treatment with independent variable • Sample size- number of subjects in study group • Positive control- a control group created to resemble a positive result • Negative control- group resembling a negative result • Placebo- accounts for human mind • Double-blind- neither patient (subject) nor doctor (test administrator) knows who is getting placebo • Confirmation bias- The tendency to view results according to predictions Clinical trials look at results in people Drugs must be proven safe by the FDA • The drug approval process is lengthy and costly • Usually costs $500m$1bn • The drug is tested in vitro first • Then on cell culture flasks • Then on animals • Then clinical trials begin Clinical trials on humans require multiple phases • Phase I: a small (20-50) group of healthy volunteers determine pharmacokinetics and pharmacodynamics of drug Anyone want to volunteer? • Phase II: larger groups of actual patients (20-300) and are designed to assess how well the drug works • Phase III: randomized controlled multicenter trials on large patient groups (300–3,000 or more) in comparison with current 'gold standard' treatment • Phase IV: After drug is released to public Sometimes clinical trials are outsourced to foreign countries Critical thinking about experiments and their results is a vital check to the scientific method • Drug compaines often suffer from confirmation bias when they fund their own studies • Clinical trials are extremely costly • Successful drugs can be extremely profitable • Vioxx revenues: $2.5bn/yr • Projected additional heart attacks: 90,000-130,000 (~30-40% fatal) Vioxx doubles risk of heart attack compared to placebo The scientific method has advanced society The scientific method is applicable beyond the hard sciences • Parents Grossly Underestimate The Influence Their Children Wield Over In-Store Purchases. • 178 parents shopping with their child in Austrian supermarkets were unobtrusively observed while strolling through the aisles…When asked how many products their children had made them buy, on average parents only reported half the number of purchases that had been secretly observed. Does excess iron decrease growth? • How can we test this? • How many groups should we use? • What size are the groups? • How shall we create the groups? • What is the dependent/independent variable? • How would this experiment be different if we used people? "An athlete who uses dietary supplements will perform better than one who doesn't." This statement would be an example of which of the following? • • • • A) Theory B) Hypothesis C) Skeptic D) A haphazard statement Defining life Characteristics of life vs. nonlife Biology is the study of life Charles Darwin, Born Feb 12, 1809 HIV, with genes corresponding to proteins What is life? • We know it when we see it • Characteristics not so easy to define • Some are more basic than others Life is orderly in a disorderly universe Seven important characteristics common to living things 1. Macromolecular composition 2. Cellular structure 3. Growth and reproduction 4. Use of energy and materials Seven important characteristics common to living things 1. Response to stimuli 2. Maintenance of homeostasis 3. Evolution and adaptation 1. All living things are composed of 4 common macromolecules • • • • Nucleic Acids Proteins Carbohydrates Lipids • DNA is a nucleic acid 2. Cellular structure Unicellular- Bacteria, Archaea, some protists Multicellular- Eukarya: plants, animals, fungi, other protists 3. Living things grow and reproduce • Bacteria reproduce by binary fission • Daughter cells of bacteria are nearly identical • But not quite… • Sexual reproduction ensures offspring are different from parents 4. All living things utilize energy and raw materials The ultimate source for energy for all ecosystems is the sun Humans and other animals get energy & raw materials from food 5. All living things respond to their environment 6. All living things regulate their internal environment against external changes • Homeostasis- “staying the same” 7. All life evolves across generations, thereby adapting to its environment • Variation in offspring allows natural selection • Variation in offspring ultimately has its roots in imperfect replication of DNA • Important noteIndividuals do NOT evolve- populations evolve Natural Selection in the Peppered Moth • Same species, 2 variants • Which one is better adapted to its current environment? • What does the future hold for this population of moths? Evolutionary history traces back to a single origin for all known life What is biology? A) the study of life B) the study of the environment C) the study of genetics D) DNA fingerprinting E) the study of biomes Major themes of biology Classification Evolution DNA Levels of organization A primary goal of biology is classification of life • Living things are primarily organized according to ancestry rather than similarity of appearance Life is organized into 3 major groups called domains- Bacteria, Archaea, and Eukarya Within the Eukaryotes, there are 4 major kingdoms- Protists, Fungi, Plants, and Animals The unifying theme of biology is evolution • The evolution of millions of species belies the common ancestry of all life • Evolution: “change over time” -Natural Selection is the mechanism by which populations evolve - “Survival (and reproduction) of the fittest”- those which best fit their environment Population with varied inherited traits Elimination of individuals with certain traits Reproduction of survivors Figure 1.15b The increasing prevalence of antibiotic – resistant pathogenic microbes is an example of evolution by natural selection in action Scientists seek to classify life according to its common ancestry All living things have DNA • DNA is an orderly, selfreplicating molecule • DNA stores all genetic information • It does not reproduce itself perfectly every single time… • As DNA evolves, living things evolve Changes in DNA are called mutations, and can be inherited • When DNA is changed, proteins change • Ear proteins in cats can cause curled ears LE 1-1a Biosphere Ecosystem Florida coast Life can be studied at many levels Community All organisms on the Florida coast Population Group of brown pelicans Organism Brown pelican LE 1-1b Organism Brown pelican Spinal cord Nerve Organ system Nervous system Brain New properties emerge at each new level of complexity Organ Brain Tissue Nervous tissue Cell Nerve cell Nucleus Organelle Nucleus Atom Molecule DNA Which of the following is not a characteristic of all living things? • A) They are composed of multiple cells. • B) They respond to stimuli. • C) They contain organic molecules such as carbohydrates, proteins, lipids, and nucleic acids. • D) They have adaptive traits.