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What is Science?. BIO 200. What is Science?. A way of investigating the world in order to form general rules about why things happen. Science is a way of knowing based on experimental or observational evidence and its interpretation.
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What is Science? BIO 200
What is Science? A way of investigating the world in order to form general rules about why things happen. Science is a way of knowing based on experimental or observational evidence and its interpretation. Science is a discipline largely defined by its primary method – the scientific method.
When did the study of science begin? Paleolithic paintings on cave walls and recordings on bones- observations 32,000 years ago
When did the study of science begin? Mesopotamian 7,000 B.C. to 6th century B.C. Medical text Astronomy Bronze surgical knives
Aristotle (384-322 B.C.) • Scientific method (observation, inductive reasoning) • Described hundreds of marine species • Dolphin is a mammal • The earth is round • Biology (spontaneous generation)- disproved by Francesco Redi (1668), an Italian doctor who proved maggots came from flies.
Ptolemy (170 A.D.)- geocentric universe Copernicus (1500’s)- heliocentric universe; not accepted until 100 years after his death Galileo (1600’s)- physicist, astronomer, scientific method
Darwin- HMS Beagle (1831) Subsidence theory Origin of Species (1859) Galapagos Islands, Ecuador
Wegener (1915) 248 mya Continental drift theory 65 mya present
Ballard & Grassle (1977) • Alvin to Galapagos • Discovered hydrothermal vents • Sulfur-rich vents 660 oF, but quickly cool to 73 oF • Unique communities • New kingdom of bacteria
The nature of science Science: A systematic process for learning about the world and testing our understanding of it The accumulated body of knowledge that results from a dynamic process of observation, testing, and discovery Science is essential: To sort fact from fiction Develop solutions to the problems we face
Global Warming Fact or Fiction?
Science as a Way of Knowing Pure Science- pursuit of knowledge Applied Science- search for practical uses of scientific knowledge Pain relief in terminal cancer patients tetradoxin
Scientists test ideas Two Primary Approaches to Science • Hypothesis-driven or experimental science. • Discovery or observational science.
Discovery/Observational Studies Some Scientific Questions Can’t Be Answered By Experimentation Discovery or observational science is still science; falsifiable hypotheses based on natural phenomenon are proposed to best account for observations.
Characteristics of Scientific Explanations Science is empirical. It relies on observation and experience. The phenomenon studied must be measurable. Phenomenon that cannot be measured: Is this painting beautiful? Does God exist? It must be consistent with known natural laws and well-established, well-documented existing theories. It must be derived objectively from independently confirmable observations. All scientific knowledge must be regarded as tentative.
Scientific statements must be testable and reproducible (i.e., valid & reliable). Hypothesis:The fibropapilloma virus causes tumors in green sea turtles. Hypothesis: Hermatypic corals exposed to temperatures above 36oC expel their symbiotic zoothanthellae. Hypothesis: Naval explosions at the thermocline layer cause hearing loss in whales. Hypothesis: Ulua are better predators.
Scientific Method A way to answer questions Must be testable & repeatable, i.e., validity and reliability Deductive Reasoning- general to specific reasoning from general theories to account for specific experimental results (theory-data collection-analysis) Inductive Reasoning- specific to general reasoning from specific observations and experiments to more general theories (data collection-analysis-theory)
Lost at Sea January1992 in the North Pacific
Rubber Duckies and Ocean currents. • Jim Ingram (NOAA scientist)- offered a reward • He graphed and studied the data as it came in. • Hypothesis: ocean currents were moving the ducks in about the same speed and direction that the currents were going!
Toy trek Researchers expect some 29,000 bath toys lost at sea in 1992 to make the ice-covered trek over the North Pole and to the North Atlantic by this summer.
The scientific method A technique for testing ideas • Observations • Question • Formulate Hypothesis • Conduct Experiment • Analyze Results • Conclusions • Discussion
Testing predictions Experiment: an activity that tests the validity of a hypothesis Variables: conditions that can be manipulated and/or measured Independent variable: a condition that is manipulated Dependent variable: a variable that is affected by the manipulation of the independent variable Controlled experiment: one in which all variables are controlled Control: the unmanipulated point of comparison Treatment: the manipulated point of comparison Data: information that is generally quantitative (numerical)
Experiments test the validity of a hypothesis Manipulative experiments yield the strongest evidence Provides the strongest type of evidence Reveal causal relationships: changes in independent variables cause changes in dependent variables But many things can’t be manipulated: long-term or large-scale questions (i.e., global climate change) Natural experiments show real-world complexity Only feasible approach for ecosystem or planet-scale Results are not so neat and clean, so answers aren’t simply black and white
Ben Franklin & the Gulf Stream Observation: Question: 1786 Hypothesis: Test hypothesis: Analyze Results: Draw Conclusion: 1996
Paine’s study on Pisaster and blue mussels What effect does starfish removal have on community structure? mussels (Mytilus) Pisaster barnacles chiton limpet
Paine’s study on Pisaster and blue mussels Keystone Species
Do sponges affect mangrove root growth? Mangrove Study
Mangrove Study Select a large sample size Randomly divide the sample into 2 groups Treat the groups equally in all ways but one Observe or make measurements Compare results
What is difference between hypothesis, theory & law? Hypothesis - “an educated guess”; a tentative explanation of phenomena. Theory - a widely accepted explanation of natural phenomena; has stood up to thorough & continual testing. Law - a statement of what always occurs under certain conditions.
Theories Cell Theory Evolution
Laws Physics, Chemistry, Math- Lots!!!! Biology: Mendelian Inheritance
The Blind Men and the Elephant (Saxe; 1816-1887) I. It was six men of Indostan To learn much inclined, Who went to see the elephant (Though all of them were blind), That each by observation Might satisfy their mind. II. The First approached the elephant, And happened to fall Against his broad sturdy side, At once began to bawl: “Bless me!—but the Elephant is very like a wall!”
III. The Second, feeling of the tusk , Cried, “Ho!—what have we here So very round and smooth and sharp? To me ‘t is mighty clear This wonder of an Elephant Is very like a spear!” IV. The Third approached the animal, And happening to take The squirming trunk within his hands, Thus boldly up and spake: “I see,” quoth he, “the Elephant Is very like a snake!”
V. The Fourth reached out his eager hand, And felt about the knee. “What most this wondrous beast is like Is might plain’” quoth he; “‘T is clear enough the Elephant Is very like a tree!” VI. The Fifth, who chanced to touch the ear, Said, “E’en the blindest man Can tell what this resembles most; Deny the fact who can, This marvel of an Elephant Is very like a fan!”
VII. The Sixth no sooner had begun About the beast to grope, Than seizing on the swinging tail That fell within his scope, “I see,” quoth he, “the Elephant Is very like a rope!” VIII. And so these men of Indostan Disputed loud and long, Each with his own opinion Exceeding stiff and strong, Though each was partly in the right, And all were in the wrong!
Moral. So, oft in these theological wars The disputants, I ween, Rail on in utter ignorance Of what each other mean, And prate about an elephant Not one of them has seen!
The Blind Men and the Elephant, Part 2, I. They talked, those men from Indostan While standing at the door, Of elephants and how they looked (This talk was such a bore!), At last they agreed that the knowledge gained Required something more. II. Perhaps each one in his own way, Did learn a bit Of the beast’s elusive mystery, But just a part of it With work, they thought, that they might see The puzzle pieces fit.
III. ‘Twas obvious to all of them For learning to progress, That they must share in what they found— Jointly sort out the mess. And seek to fully understand Elephants, more or less. IV. Some worked alone and some in teams, In both the field and lab. Models were made: some soft, some hard Some good, some pretty bad. But when they pooled the useful work, And truth they made a grab.
V. They checked each other’s methods out, Some kept, some put asunder. To use the ones which passed the test Reduced the chance of blunder. Then they’d trust what they had learned Of elephants’ fine wonders. VI. They made great strides in what they knew Of the nature of the beast. Of what and where and how and why They knew much more at least. For blind men learned how best to learn And vision soon increased!
Inquiry • What is the difference between a hypothesis, theory and law? • Can a theory ever be proven? • In the mangrove study, what is the dependent variable? • State Ben Franklin’s hypothesis. • In Paine’s study on Pisaster, what role did blue mussels play?
QUESTION: Review Which is the correct order of the scientific method? Observation, question, hypothesis, testing, results Hypothesis, observation, testing, results Question, observation, testing, results, hypothesis observation, question,testing, hypothesis, results
QUESTION: Interpreting Graphs and Data What happens if test results reject a hypothesis? The scientist formulates a new hypothesis. It shows the test failed. The scientist should be fired. The scientist used faulty data .