August 2002
In 1837 Darwin started his “B” notebook on Transmutation of Species, and on page 36 wrote “I think” above the first evolutionary tree. Photo: Museum of Natural History in Manhattan.
Charles Darwin, Gregor Mendel, James Watson and Francis Crick — every biology student encounters these great heroes in the course of their studies. Their discoveries are occasions to celebrate. As role models, they may even inspire careers in science. More deeply, they provide glimpses into real biology in action. Every teacher may thus consider history as a valuable resource for teaching the process of science more effectively. Students enjoy stories. Accounts of scientific discovery, in particular, are compelling. For the resourceful teacher, histories are also opportunities that are as potentially instructive as they are engaging. They are especially apt for lessons in the nature of science, now a widespread goal in science education.3,5,14
Darwin’s nose, Mendel’s luck and Watson’s play
Consider for example, Darwin’s nose. Many textbooks portray the significance of Darwin’s voyage on the Beagle. Yet Darwin almost did not go. His passage was provided in part to provide socialty for the captain, Robert FitzRoy. FitzRoy worried that the shape of Darwin’s nose did not reflect the criteria of “sufficient energy and determination” for the trip! An amicable first meeting apparently persuaded him.4 The anecdote is amusing, yet also informative:
- First, one can see the import of physiognomy, a practice now regarded as pseudoscience: a cautionary tale, even for today.7
- Second, one sees how science can hinge on odd particulars of personality and chance, not just deliberate method.
- Finally, FitzRoy’s criteria ultimately mattered to science.
For the same reason, Darwin’s social class was important. FitzRoy, due to his own status, required a companion of equal peerage. Darwin’s family background may seem incidental. But it also provided Darwin the leisure to pursue his travels — and supported his continued research once he returned. Science involves time and money. And Darwin’s many discoveries relied in part on his wealth.
Consider, too, how Mendel discerned the mathematical patterns of inheritance. Mendel reported on seven, now renowned, pairs of traits in peas: tall/short, wrinkled/smooth, etc. However, not all traits in peas show clearly dichotomous ratios of recombination — nor every pair independent assortment.
Was Mendel lucky? Perhaps he knew more at the outset than he let on? Many presume that Mendel tested a clear hypothesis. That fits the textbook version of the scientific method, at least. But his strategy seems quite different. He apparently followed twenty-two traits, tracking various combinations, hoping patterns would emerge.8 Only a few pure-breeding forms were available commercially. Mendel worked with what he had. He searched somewhat blindly and ignored confusing results. Still, he made an important discovery.
Finally, consider James Watson and Francis Crick developing the double helix model of DNA.18 Watson’s “method” underscores the creative dimension of science, sometimes relying on unexpected events and play. Watson, following Linus Pauling, first considered a triple helix. Then he paired nucleotide bases on the outside of a backbone. Later he paired like with like. How did he finally discover the complementary pairs? He cut out cardboard templates of the bases. Then Watson played with them, like pieces of a jigsaw puzzle. Watson’s officemate pointed out that the shapes of the guanine and thymine bases were likely wrong. The revised bases, combined and turned appropriately, matched.
These three stories about great discoveries in biology, as brief as they are, offer important lessons about how science happens. Science is more complex — and more interesting! — than the method commonly profiled in textbooks. History is valuable because it portrays this richness.
Teaching how science works: Monthly case studies
Teachers should go beyond the occasional anecdote, however. To fully appreciate the many dimensions of scientific practice, students must delve into historical case studies. In case studies, students see the process of science and the context of science in concert. Appropriate questions to address in any episode include:
- What motivated the work?
- How did the individual encounter a particular problem or question?
- How did the scientist collect the relevant information? How was its reliability ensured?
- Were the claims criticized? Why?
- How were alternative explanations addressed?
- How was disagreement resolved?
- How was the work funded or supported?
- What ethical, economic, political, cultural or gendered issues may have accompanied the research?
Students learn even more vividly when immersed in the historical context. They may be invited to tackle some problems themselves: interpreting results, finding alternative explanations, designing experiments, persuading critics, assessing ethical dilemmas, etc.10 This helps them develop their own thinking skills, especially when they can compare their work to how the earlier scientists reasoned. Students may also re-enact historical debates (for example, about spontaneous generation16 or about color vision17. Reviving the uncertainty underscores the challenge of interpreting evidence before the answer is known.
Students peering virtually over the shoulders of scientists learn how they reach conclusions. Not all research follows the formula of “the scientific method” so often profiled in textbooks. Biologists use a diverse toolbox of methods. They:
- build models
- apply analogies
- induce patterns
- allow results to “self-select” themselves
- harvest raw data for archives
- look for statistical correlations
- run computer simulations
- tinker with experimental apparatus
- test predictions derived indirectly from hypotheses
Biology now permeates personal and public decision-making, from climate change and pesticides to cloning and stem cells. Claims are supported by many methods. Teachers need to prepare individuals to interpret the available evidence and to pose relevant further questions, whatever the case.
Students typically enter biology classes with notions of how science happens. They often believe romanticized depictions of extraordinary genius and rare moments of insight. They find no reason to question these widespread myths. For any biologist who toils in the lab or field, checks every control, or struggles to develop a new experimental procedure, the myths are fictions. Of course, good history can remedy such misconceptions.2 But the history itself must be well informed. Teachers should thus ensure that their own sources are reliable and complete. They should also convey historical context well.1
Every case study adds depth to a student’s knowledge of science. One episode alone is often enough to transform preconceived stereotypes of scientists, say, or of instant certainty. However, science is complex and textured. The ideal is several case studies in succession. Multiple episodes display the diversity, as well as highlight common themes. Hence, ideally, introduce at least one case study each month. Other lessons may thereby be displaced. But the trade-offs work. Anything that is learned from a book, students can learn when the occasion demands. The skills of interpreting what they read or hear from scientists cannot. Skills and perspective need modeling, practice and guidance. Teachers will find that students readily affirm the value of what they learn from historical case studies.
More lessons in the nature of science
Further lessons benefit those who delve even deeper into history. For example, scientific ideas change. Sometimes they reveal earlier errors. Sometimes, research is inconclusive or interpretation of results is uncertain. This, too, can be important for public policy and decision-making. Students need to learn the limits, as well as the foundations of scientific claims. Again, history is a powerful teaching tool. Episodes of conceptual change help reveal how the meaning of evidence sometimes shifts dramatically.
Consider Christiaan Eijkman and the cause of beriberi.6,10 Here, a student sees both the power and the limit of controlled experiments.
In the 1890s, Eijkman applied newly established germ theory and saw the disease as bacterial.
Through a series of accidents, he believed that he had isolated the source of the microorganism in white rice.
For confirmation, he coordinated a large controlled study showing how a white rice diet — and not other hygienic factors — correlated to beriberi among over one-quarter million prisoners in Java.
Based on his findings, diets changed and beriberi declined.
Eijkman had not considered, however (and his successor later showed), that the white rice was deficient in an essential nutrient (later identified as the vitamin thiamine). Eijkman even rejected the idea when first proposed!
He was wrong about the bacterium. He erred. Still, his achievement was significant and earned him a share in the 1929 Nobel Prize.
Other stories of error may convey a less noble image of science. Science is, ultimately, a human enterprise. And sometimes scientists express cultural bias. For example, in the U.S. in the 1950s, a group of researchers did not treat some syphilis patients because they wanted to study the advanced stages of their disease. They did not seek informed consent. The subjects were all Negroes. For us now, the racism that allowed the lapse in research ethics is painfully obvious.12 It shows that biologists are not immune to human prejudices just because they are scientists. Indeed, “scientific” results have even been used to support racist ideologies. Studies of intelligence — first, based on skulls, and later on IQ — typically endeavored to show that the researcher’s own “kind” was superior. The scientists mostly seemed unaware of their own errors, even while they claimed the authority of science.9
Concepts of anatomy, behavior, and nature have likewise sometimes been shaped by gendered perspectives.11,15 It is all too easy to imagine that the banner of science legitimates such studies. A scientifically literate individual is thus familiar with such cases and is prepared to analyze and critique science, especially where power and profit are at stake.
A valuable teaching tool
Finally, history also offers teachers tools for teaching basic content. For example, history provides one framework for student motivation. Context gives meaning to biological questions. Arranged sequentially, they can often structure curriculum.13 Students also often share preconceptions with their historical counterparts. The experience of the past offers clues about how to guide students to more sophisticated views. History thus offers more than a parade of heroic discoveries or asides for human interest. A healthy approach to science adopts history as a tool for teaching the process of science: reasoning patterns and standards of evidence, as well as their limits. History is also essential for portraying the nature of science fully, including its human and cultural dimensions. For non-scientists, in particular, history makes biology engaging and informative.
© 2002, American Institute of Biological Sciences. Educators have permission to reprint articles for classroom use; other users, please contact editor@actionbioscience.org for reprint permission. See reprint policy.
