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Introduction to Biology Prologue: The Molecular Perspective Prologue: Packet #1 Biology in Your World Biology is believed to be the most influential science of the 21st century Cancer cures? Genetic engineering / counseling / cloning Stem cells But, just because we can…should we? Prologue: Packet #1 Ethics and Biology Using Knowledge Wisely Ethics – a system of moral principles to distinguish right from wrong What are your ethics based upon? Public Policy – laws and regulations that govern how science is applied What role do you play in deciding public policy? Example http://www.csmonitor.com/USA/Justice/2011/0429/Stem-cell-research-Court-gives-Obama-a-victory-but-policy-still-on-trial Prologue: Packet #1 What is science? An organized way of using evidence to learn about the natural world The body of knowledge that scientists have accumulated over time It is not based on belief or faith, magic, or legend but on actual evidence. Pseudoscience – associating real science to some supernatural occurrence or pattern without evidence EXs: Palm reading, Astrology, Alchemy, Intelligent Design Daily Horoscope Prologue: Packet #1 Important Scientific Skills Observing – process of gathering information using your senses in a careful, orderly way Inferencing – making a logical interpretation based on prior knowledge or experience Did not eyewitness Example… Baby was asleep upstairs – heard a loud thump – heard crying What inferences can we make? http://www.philtulga.com/Riddles.html - Inferencing game Prologue: Packet #1 The Scientific Process Analyzes problems through TESTING Hypothesis – possible explanation of observations that are testable through experimentation or observation. Theory – a repeatedly tested hypothesis that accurately explains observations and predicts future occurrences. “If….then” Cell theory, gene theory Laws – widely accepted and repeatedly tested theories Newton’s Law, Thermodynamics Prologue: Packet #1 Good Scientists…. Are skeptics: they question existing ideas and new hypotheses Are open-minded: they are always willing to consider new ideas when evidence demands it Rely on basic natural laws: they understand that the universe functions as a system of interacting processes Repeat experiments: through an immense amount of research a certain hypothesis might become so wellsupported that scientists consider it a theory Keep up with new knowledge gained through research: they continually revise and re-evaluate ideas. NOTHING IS “FACT” Prologue: Packet #1 What is Life? A fundamental scientific question Prologue: Packet #1 “Life is Organized” Smallest / most simple Atoms C,H,O,N,P,S Molecules Organelles Cells Tissues Organs Organ Systems Organism Species Population Community Ecosystem Biome Ex: Tundra, desert, temperate forest Biosphere Largest / most complex Prologue: Packet #1 How did life begin? An Idea The Oparin-Haldane Hypothesis (1920s) Verified by Miller-Urey (1953) Built an apparatus to mimic early earth: Reducing atmosphere; methane, ammonia, hydrogen Boiled water, shocked it, cooled it Atoms bumped together & formed hydrocarbons and amino acids! Prologue: Packet #1 Living things… Are made up of units called CELLS Are based on a universal GENETIC code REPRODUCE GROW and DEVELOP CHANGE over time (evolve) Obtain & Use Materials and ENERGY Maintain an Internal BALANCE = homeostasis RESPOND to their Environment Prologue: Packet #1 EVOLVE Why does a duck have a rounded bill and a heron have a long pointed bill? All organisms are uniquely adapted for their environments. Scientists know that over long periods of time organisms have changed or adapted to better survive in their environments. They call this slow process of change evolution. Natural Selection: Those best adapted survive and Prologue: Packet #1 reproduce. Life BEGINS… CELLS with DNA are passed on through REPRODUCTION An organism GROWS and DEVELOPS to an age where it can REPRODUCE. Over time, subtle changes are introduced through mutation of DNA. These changes are selected for, leading to EVOLUTION of a population. Prologue: Packet #1 A Mechanism for Evolution: Science at Work The formulation of a Theory An Example of The Scientific Process Prologue: Packet #1 Jean Baptiste Lamarck (1744 – 1829) Organisms change over time by using or not using certain features. These acquired characteristics are then passed onto offspring “Use or Disuse” “If a male and a female increase the size of their muscles through weight training, then their children will be born with large muscles.” Mr. Palmé as a 5 yr old Prologue: Packet #1 Was Lamarck right? Prologue: Packet #1 Charles Darwin (1809 – 1882) A naturalist on a 5-year voyage of the Beagle around the world Observed numerous, diverse organisms Influenced by the geologists, Charles Lyell and James Hutton, who proposed uniformitarianism (everything in the universe acts under the same laws of physics) Geological forces existing in the past are similar to the forces of today and in the future Proposed the mechanism of evolution Natural Selection Prologue: Packet #1 Theory of Natural Selection Organism best suited (specific traits/characteristics) for the environment would survive and reproduce. The suitable traits would be passed on to their offspring. The specific traits or characteristics are called adaptations Prologue: Packet #1 Is this how Evolution works? Prologue: Packet #1 Survival of the Fittest Thomas Malthus (economist) noticed that species numbers exceed food supply In order to pass on characteristics, an organism must eat enough to live to reproduce. Ultimately, the only organisms alive are those with beneficial adaptations What are some adaptations? Prologue: Packet #1 Darwin’s Predictions If organisms with favorable variations are most likely to survive and reproduce, then those organisms with unfavorable variations would be less successful at reproduction and die out. If organisms with those favorable adaptations become so different from members of the original species that they can no longer reproduce together, then a new species may have evolved. Prologue: Packet #1 Was Darwin Right? Whose to say but… Experiments repeatedly show same results Descent with Modification – related organisms share a common ancestor The greater the similarity between two groups of organisms, the closer their relationship How is this studied today? Prologue: Packet #1