Environmental Problems, Their Causes, and Sustainability 1

CTIONSWhat Is Harmingthe Robins?Suppose a scientist observes anabnormality in the growth ofrobin embryos in a certain area.CONNECTIONS She knows the area has beensprayed with a pesticide and suspectsthe chemical may be causing the abnormalitiesshe has observed.To test this hypothesis, the scientist carries out acontrolled experiment. She maintains two groups ofrobin embryos of the same age in the laboratory.Each group is exposed to exactly the same conditionsof light, temperature, food supply, and so on,except the embryos in the experimental group areexposed to a known amount of the pesticide inquestion.The embryos in both groups are then examinedover an identical period of time for the abnormality.If she finds a significantly larger number of theabnormalities in the experimental group than inthe control group, the results support the idea thatthe pesticide is the culprit.To be sure no errors occur during the procedure,the original researcher should repeat the experimentseveral times. Ideally one or more otherscientists should repeat the experimentindependently.Critical ThinkingCan you find flaws in this experiment that mightlead you to question the scientist’s conclusions?(Hint: What other factors in nature—not the laboratory—andin the embryos themselves could possiblyexplain the results?)cannot be absolutely sure someone will drop an objectthat does not fall to the earth’s surface.Deductive reasoning involves using logic to arriveat a specific conclusion based on a generalization orpremise. It is a form of “top-down” reasoning that goesfrom the general to the specific. For example,Generalization or premise: All birds have feathers.Example: Eagles are birds.Deductive conclusion: All eagles have feathers.The conclusion of this syllogism (a series of logicallyconnected statements) is valid as long as the premise iscorrect and we do not use faulty logic to arrive at theconclusion.Deductive and inductive reasoning and criticalthinking skills (p. 3) are important scientific tools. Butscientists also try to come up with new or creative ideasto explain some of the things they observe in nature.Often such ideas defy conventional logic and currentscientific knowledge. According to physicist AlbertEinstein, “There is no completely logical way to a newscientific idea.” Intuition, imagination, and creativityare as important in science as they are in poetry, art,music, and other great adventures of the human spirit,as reflected in scientist Warren Weaver’s quotationfound at the opening of this chapter.One of the exciting things about science is that it isnever complete. Each discovery unearths new unansweredquestions in an ongoing quest for knowledgeabout how the natural world works. This is one reasonwhy people choose this profession.How Valid Are the Results of Science?Very Reliable But Not PerfectScientists try to establish that a particular model,theory, or law has a very high probability of beingtrue.Scientists can do two major things. First, they candisprove things. Second, they can establish that a particularmodel, theory, or law has a very high probabilityor degree of certainty of being true. However, likescholars in any field, scientists cannot prove that theirtheories, models, and laws are absolutely true.Although it may be extremely low, some degree ofuncertainty is always involved in any scientific theory,model, or law. Most scientists rarely say somethinglike, “Cigarettes cause lung cancer.” Rather, the statementmight be phrased, “There is overwhelmingevidence from thousands of studies that indicate a significantrelationship between cigarette smoking andlung cancer.”Most scientists also rarely use the word proof.When scientists hear someone say we should not takea scientific finding seriously because it has not beenabsolutely proven they know that this person eitherknows little about the nature of science or is using adebating or advertising trick to cast doubt on a widelyaccepted scientific finding. Scientists tend to use wordslike projections and scenarios to describe what is likely tohappen in nature instead of making predictions or forecastsabout what will happen.What Is the Difference between FrontierScience and Sound Science? Preliminaryand Well-Tested ResultsScientific results fall into those that have not beenconfirmed (frontier science) and those that have beenwell tested and widely accepted (sound science).News reports about science often focus on two things:new so-called scientific breakthroughs, and disputesbetween scientists over the validity of preliminary andhttp://biology.brookscole.com/miller1435