BIOL1307: General Biology II - Biological Principles - PDF

BIOL1307: General Biology II Biological Principles Characteristics of Life, Historical Figures and the Scientific Method  Biology Biology- – Study of life – What characteristics do all life forms share?  What is Science? There are 3 main ways that...

BIOL1307: General Biology II Biological Principles Characteristics of Life, Historical Figures and the Scientific Method  Biology Biology- – Study of life – What characteristics do all life forms share?  What is Science? There are 3 main ways that humans try to explain our world: 1. Religion 2. Philosophy 3. Science What is Biology? I. Characteristics of Life A. CHEMICAL COMPLEXITY Living organisms assemble and use large macromolecules. Nucleic acids DNA, RNA Proteins Amino acid chains Fig 1.2 Carbohydrates Sugars, chitin Lipids Fats, waxes, oils What is Biology? I. Characteristics of Life What is Biology? I. Characteristics of Life B. H I E R A R C H I C A L O R G A N I Z AT I O N Living organisms exist within Biosphere Individuals Above the Individual more complex hierarchical levels. Ecosystem Appearance of a new character Community at a given level of organization is called emergence. Species Arise from interactions among the component parts of a Population system. Multicellular Individual Cell Non-living Molecule Atom Subatomic particle What is Biology? I. Characteristics of Life C. REPRODUCTION Reproduction is seen at many hierarchical levels. DNA, Cells, Individuals, Species Fig 1.5 What is Biology? I. Characteristics of Life D. GENETIC PROGRAM All life forms have DNA Possible exception = Viruses Some have closely related RNA Debatable if viruses are “alive” DNA contains genetic information Genes Same rules are used to translate information in all life forms. “Universal” genetic code Fig 1.6 What is Biology? I. Characteristics of Life E. METABOLISM All organisms acquire and use energy. All organisms use the same basic chemical processes to transfer energy. What is Biology? I. Characteristics of Life F. DEVELOPMENT All organisms have developmental phases Animals- Zygote juvenile breeding adult post-breeding Fig 1.8 adult What is Biology? I. Characteristics of Life G. ENVIRONMENTAL INTERACTIONS All organisms respond to their environment. Light, temperature, other individuals, etc… Fig 1.9 Adaptations evolve so that organisms respond appropriately. What is Biology? I. Characteristics of Life H. LIFE OBEYS PHYSICAL LAWS Vitalism rejected Life has a mystical vital force First law of thermodynamics Second law of thermodynamics What is Biology? I. Characteristics of Life H. LIFE OBEYS PHYSICAL LAWS First law of thermodynamics Conservation of energy Energy is neither created or destroyed Photosynthesis simply changes the form of energy Sunlight energy to carbohydrates. Metabolism transfers energy from one organism to another What is Biology? I. Characteristics of Life H. LIFE OBEYS PHYSICAL LAWS Second law of thermodynamics Physical systems proceed toward a state of increasing disorder Entropy Energy is lost at each trophic level. Plant - herbivore - carnivores What is Biology? I. Characteristics of Life H. LIFE OBEYS PHYSICAL LAWS Survival, growth and development requires a constant supply of energy. Metabolism provides this energy. What is Science? I. The Evolution of Science A. NATURE OF SCIENCE Science comes from the Latin Scientia – to know Seeks natural explanations for natural phenomena. Explanations in the form of hypotheses and theories. Empirical Based on observations What is Science? I. The Evolution of Science A. NATURE OF SCIENCE Repeatability Shared Information Peer-reviewed and tested What is Science? I. The Evolution of Science B. LIMITATIONS OF SCIENCE Science cannot... Explain or invoke supernatural phenomena nature = observable universe Address basic philosophical questions "Why are we here?" Direct ethical decisions Should one… choose sex of your offspring promote genetically modified foods Address theology Beliefs are not testable What is Science? II. Historical Figures of Science Aristotle 384 – 322 BC student of Plato emphasized importance of empiricism = relying on or derived from observation or experiment studied: behavior and habitat of birds seasonal effects on reproduction animal geography hibernation and migration color change feeding habits symbiosis What is Science? II. Historical Figures of Science Scientific Revolution roughly 1550 - 1700 fundamental change in the approach to explaining phenomena that are not understood unofficially begins with Copernicus What is Science? II. Historical Figures of Science Scientific Revolution Mikołaj Kopernik (Nicolaus Copernicus) 1473 - 1543 Polish astronomer first to argue for heliocentric view of solar system What is Science? II. Historical Figures of Science Scientific Revolution Johannes Kepler Galileo Galilei German, Italian, 1564 – 1571 – 1630 1642 laws of empirical planetary support for motion Copernicanism René Decartes Isaac Newton 1596 – 1650 English, 1643 – French mathematician 1727 developed analytical physicist, geometry Discourse on Method mathematician, 4 precepts that astronomer emphasized objective observations What is Science? II. Historical Figures of Science so out of the scientific revolution comes the formalization of the scientific method summarized by… Karl Popper 1902 – 1994 emphasized falsifiability in science Pointed out the elusiveness of “proof” Strong hypotheses are not proven correct, they survive attempts to disprove What is Science? III. Essentials of Scientific Inquiry Science – modern definition a pursuit of knowledge using observations, questions, hypotheses, deductions, and conclusions that produces natural explanations for natural phenomena that take the form of hypotheses and theories that can be falsified. What is Science? III. Essentials of Scientific Inquiry Essentials of scientific inquiry: 1) It is guided by natural explanations; 2) It has to be explanatory by reference to natural mechanisms; 3) It is testable against the empirical world; What is Science? III. Essentials of Scientific Inquiry Essentials of scientific inquiry: 4) Its conclusions are tentative, i.e. are not necessarily the final word; 5) It is falsifiable. What is Science? III. Essentials of Scientific Inquiry _____________: observation repeatedly verified _________________________: hypothesis of broad scope with overwhelming evidence ____________________________: powerful theory that guides a field of knowledge ___________________: description of how a system behaves under specific circumstances What is Science? IV. The Scientific Method A. (HYPOTHETICO-DEDUCTIVE) SYSTEM 1. Make observations 2. Ask questions 3. Form hypotheses, or tentative answers to the questions make predictions based on these hypotheses Null hypothesis: hypothesis of no effect or no difference ex.______________________________________________ __________________________________________ Alternative hypothesis: hypothesis that there is an effect or difference ex.________________________________________ __________________________________________ What is Science? IV. The Scientific Method A. (HYPOTHETICO-DEDUCTIVE) SYSTEM 4. Test hypotheses & predictions make additional observations conduct experiments 5. Form conclusions hypothesis accepted or rejected acceptance does not = proof 6. Publication, peer review, intense scrutiny What is Science? IV. The Scientific Method If results of continued testing support hypothesis, it may come to be considered a theory If results do not support hypothesis, it may be modified or abandoned Most tests of hypotheses are of 3 types… What is Science? IV. The Scientific Method B. HYPOTHESIS TESTING Observational methods Experimental manipulations Other methods not covered sample size is crucial in all studies. – accurate sampling of patterns despite occasional atypical data points. – application of statistical methods to quantify levels of support. What is Science? IV. The Scientific Method C. OBSERVATIONAL METHODS Test without manipulation. Compare groups Ex. _________________________ Often deal with _______________ causation What is Science? IV. The Scientific Method C. OBSERVATIONAL METHODS Ex. peppered moth studies in England Observations: moths hide on trees polluted areas have trees with dark, soot- covered bark moths in polluted areas are darker than in clean areas where trees are grey Hyp. 1: moth colors are not adaptations to tree bark Hyp. 2: moth colors are adaptations to match tree bark What is Science? IV. The Scientific Method C. OBSERVATIONAL METHODS Compare colors of moths before and after pollution levels drop Prediction under Hyp.1 (moth colors are not adaptations to tree colors): # dark moths should not change Prediction under Hyp. 2 (moth colors are adaptations to tree colors): # dark moths should decrease after pollution levels drop What is Science? IV. The Scientific Method C. OBSERVATIONAL METHODS Fig. 1.11 What is Science? IV. The Scientific Method D. EXPERIMENTAL MANIPULATIONS _____________________ one variable manipulated to learn its effects _____________________ manipulation w/held for a clean comparison; checks assumptions often deal with _______________ causation What is Science? IV. The Scientific Method D. EXPERIMENTAL MANIPULATIONS Ex. Function of Wing display in Tephritid Flies Observations: Flies have banded wings Wings are displayed when disturbed. What is Science? IV. The Scientific Method D. EXPERIMENTAL MANIPULATIONS Do flies mimic jumping spiders to scare off predators? Hyp1- ______________________________________ Hyp2- ______________________________________ Hyp3- ______________________________________ What is Science? IV. The Scientific Method D. EXPERIMENTAL MANIPULATIONS Hypothesis test: offer flies to spiders; compare response to fruit flies and house fly & make manipulations What is Science? IV. The Scientific Method D. EXPERIMENTAL MANIPULATIONS Control groups make sure that experimental manipulations are not clouding the data. What is Science? IV. The Scientific Method D. EXPERIMENTAL MANIPULATIONS Data consistent with _____________