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A standard genetic/bioinformatic activity in the genomics era is the identification within DNA sequences of an "open reading frame" (ORF) that encodes a polypeptide sequence. As an educational introduction to such a search, we provide a webapp that composes, displays for solution, and then solves short DNA exemplars with a single ORFTo the Editor: We wish to bring a new Web resource to the attention of CBE—Life Sciences Education readers.When being introduced to the central dogma of nucleic acid transactions, students are often required to identify the 5′→3′ DNA template strand in a double-stranded DNA (dsDNA) molecule; transcribe an antiparallel, complementary 5′→3′ mRNA; and then translate the mRNA codons 5′→3′ into an amino acid polypeptide by means of the genetic code table. Although this algorithm replicates the molecular genetic process of protein synthesis, experience shows that the series of left/right, antiparallel, and/or 5′→3′ reversals is confusing to many students when worked by hand. Students may also obtain the “right” answer for the “wrong” reasons, as when the “wrong” DNA strand is transcribed in the “wrong” 3′→5′ direction, so as to produce a string of letters that “translates correctly.”In genetics and bioinformatics education, we have found it more intuitively appealing to demonstrate and emphasize the equivalence of the mRNA to the DNA sense strand complement of the template strand. The sense strand is oriented in the same 5′→3′ direction and has a sequence identical to the mRNA, except for substitution of thymidine in the DNA for uracil in the mRNA. It is thus more computationally efficient to “read” the polypeptide sequence directly from this strand, with mental substitution of thymidine in the triplets of the genetic code table. (By definition, “codons” occur only in mRNA: the equivalent three-letter words in the DNA sense strand may be designated “triplets.”) This is the same logic used in DNA “translation” software programs.A further constraint often imposed on dsDNA teaching exemplars is that five of the six possible reading frames are “closed” by the occurrence of one or more “stop” triplets, and only one is an open reading frame (ORF) that encodes an uninterrupted polypeptide. We designate this the “5&1” condition. The task for the student is to identify the ORF and “translate” it correctly. Other considerations include correct labeling of the sense and template DNA strands, their 5′ and 3′ ends (and of the mRNA as required), and the amino (N) and carboxyl (C) termini of the polypeptide.Thus, instructors face the logistical challenge of creating dsDNA sequences that satisfy the “5&1” condition for homework and exam questions. Instructors must compose sequences with one or more “stops” in the three overlapping read frames of one strand, while simultaneously creating two “stopped” frames and one ORF in the other. We have explored these constraints as an algorithmic and computational challenge (Carr et al., 2014 ). There are no “5&1” exemplars of length L ≤ 10, and the proportion of exemplars of length L ≥ 11 is very small relative to the 4L possible sequences (e.g., 0.0023% for L = 11, 0.048% for L = 15, 0.89% for L = 25). This makes random exploration for such exemplars inefficient.We therefore developed a two-stage recursive search algorithm that samples 4L space randomly to generate “5&1” exemplars of any specified length L from 11 ≤ L ≤ 100. The algorithm has been implemented as a Web application (“RandomORF,” available at www.ucs.mun.ca/~donald/orf/randomorf). Figure 1 shows a screen capture of the successive stages of the presentation. The application requires JavaScript on the computer used to run the Web browser.Open in a separate windowFigure 1.Successive screen captures of the webapp RandomORF. First panel: the Length parameter is the desired number of base pairs. Second panel: Clicking the “Generate dsDNA” button shows the dsDNA sequence to be solved, with labeled 5′ and 3′ ends. The button changes to “Show ORF.” Third panel: A second click shows the six reading frames, with the ORF highlighted. Here, the ORF is in the sixth reading frame on the bottom (sense) strand. The polypeptide sequence, read right to left, is N–EITHLRL–C, where N and C are the amino and carboxyl termini, respectively. The conventional IUPAC single-letter abbreviations for amino acids are centered over the middle base of the triplet; stop triplets are indicated by asterisks (*).The webapp provides a means for students to practice identifying ORFs by efficiently generating many examples with unique solutions (Supplemental Material); this can take the place of the more standard offering of a small number of set examples with an answer key. The two-stage display makes it possible for problems to be worked “cold,” with the correct ORF identified only afterward. For examinations, any exemplar may be presented in any of four ways, by transposing the top and bottom strands and/or reversing the direction of the strands left to right. Presentation of the 5′ end of the sense strand at the lower left or upper or lower right tests student recognition that sense strands are always read in the 5′→3′ direction, irrespective of the “natural” left-to-right and/or top-then-bottom order. We intend to modify the webapp to include other features of pedagogical value, including constraints on [G+C] composition and the type, number, and distribution of stop triplets. We welcome suggestions from readers.  相似文献   

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The scale and importance of Vision and Change in Undergraduate Biology Education: A Call to Action challenges us to ask fundamental questions about widespread transformation of college biology instruction. I propose that we have clarified the “vision” but lack research-based models and evidence needed to guide the “change.” To support this claim, I focus on several key topics, including evidence about effective use of active-teaching pedagogy by typical faculty and whether certain programs improve students’ understanding of the Vision and Change core concepts. Program evaluation is especially problematic. While current education research and theory should inform evaluation, several prominent biology faculty–development programs continue to rely on self-reporting by faculty and students. Science, technology, engineering, and mathematics (STEM) faculty-development overviews can guide program design. Such studies highlight viewing faculty members as collaborators, embedding rewards faculty value, and characteristics of effective faculty-development learning communities. A recent National Research Council report on discipline-based STEM education research emphasizes the need for long-term faculty development and deep conceptual change in teaching and learning as the basis for genuine transformation of college instruction. Despite the progress evident in Vision and Change, forward momentum will likely be limited, because we lack evidence-based, reliable models for actually realizing the desired “change.”
All members of the biology academic community should be committed to creating, using, assessing, and disseminating effective practices in teaching and learning and in building a true community of scholars. (American Association for the Advancement of Science [AAAS], 2011 , p. 49)
Realizing the “vision” in Vision and Change in Undergraduate Biology Education (Vision and Change; AAAS, 2011 ) is an enormous undertaking for the biology education community, and the scale and critical importance of this challenge prompts us to ask fundamental questions about widespread transformation of college biology teaching and learning. For example, Vision and Change reflects the consensus that active teaching enhances the learning of biology. However, what is known about widespread application of effective active-teaching pedagogy and how it may differ across institutional and classroom settings or with the depth of pedagogical understanding a biology faculty member may have? More broadly, what is the research base concerning higher education biology faculty–development programs, especially designs that lead to real change in classroom teaching? Has the develop-and-disseminate approach favored by the National Science Foundation''s (NSF) Division of Undergraduate Education (Dancy and Henderson, 2007 ) been generally effective? Can we directly apply outcomes from faculty-development programs in other science, technology, engineering, and mathematics (STEM) disciplines or is teaching college biology unique in important ways? In other words, if we intend to use Vision and Change as the basis for widespread transformation of biology instruction, is there a good deal of scholarly literature about how to help faculty make the endorsed changes or is this research base lacking?In the context of Vision and Change, in this essay I focus on a few key topics relevant to broad-scale faculty development, highlighting the extent and quality of the research base for it. My intention is to reveal numerous issues that may well inhibit forward momentum toward real transformation of college-level biology teaching and learning. Some are quite fundamental, such as ongoing dependence on less reliable assessment approaches for professional-development programs and mixed success of active-learning pedagogy by broad populations of biology faculty. I also offer specific suggestions to improve and build on identified issues.At the center of my inquiry is the faculty member. Following the definition used by the Professional and Organizational Development Network in Higher Education (www.podnetwork.org), I use “faculty development” to indicate programs that emphasize the individual faculty member as teacher (e.g., his or her skill in the classroom), scholar/professional (publishing, college/university service), and person (time constraints, self-confidence). Of course, faculty members work within particular departments and institutions, and these environments are clearly critical as well (Stark et al., 2002 ). Consequently, in addition to focusing on the individual, faculty-development programs may also consider organizational structure (such as administrators and criteria for reappointment and tenure) and instructional development (the overall curriculum, who teaches particular courses). In fact, Diamond (2002) emphasizes that the three areas of effort (individual, organizational, instructional) should complement one another in faculty-development programs. The scope of the numerous factors impacting higher education biology instruction is a realistic reminder about the complexity and challenge of the second half of the Vision and Change endeavor.This essay is organized around specific topics meant to be representative and to illustrate the state of the art of widespread (beyond a limited number of courses and institutions) professional development for biology faculty. The first two sections focus on active teaching and biology students’ conceptual understanding, respectively. The third section concerns important elements that have been identified as critical for effective STEM faculty-development programs.  相似文献   

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Plant Behavior     
Plants are a huge and diverse group of organisms ranging from microscopic marine phytoplankton to enormous terrestrial trees. Stunning, and yet some of us take plants for granted. In this plant issue of LSE, WWW.Life Sciences Education focuses on a botanical topic that most people, even biologists, do not think about—plant behavior.Plants are a huge and diverse group of organisms (Figure 1), ranging from microscopic marine phytoplankton (see http://oceandatacenter.ucsc.edu/PhytoGallery/phytolist.html for beautiful images of many species) to enormous terrestrial trees epitomized by the giant sequoia: 300 feet tall, living 3000 years, and weighing as much as 3000 tons (visit the Arkive website, www.arkive.org/giant-sequoia/sequoiadendron-giganteum, for photos and basic information). Stunning, and yet some of us take plants for granted, like a side salad. We may see plants as a focal point during the blooming season or as a nice backdrop for all the interesting things animals do. For this plant issue of CBE—Life Sciences Education, I am going to focus on a botanical topic that most people, even biologists, do not think about—plant behavior.Open in a separate windowFigure 1.Plants are very diverse, ranging in size from microscopic plankton (left, courtesy of University of California–Santa Cruz Ocean Data Center) to the biggest organisms on our planet (right, courtesy Arkive.org).Before digging into plant behavior, let us define what a plant is. All plants evolved from the eukaryotic cell that acquired a photosynthetic cyanobacterium as an endosymbiont ∼1.6 billion years ago. This event gave the lineage its defining trait of being a eukaryote that can directly harvest sunlight for energy. The cyanobacteria had been photosynthesizing on their own for a long time already, but this new “plant cell” gave rise to a huge and diverse line of unicellular and multicellular species. Genome sequences have shed light on the birth and evolution of plants, and John Bowman and colleagues published an excellent review titled “Green Genes” several years ago in Cell (www.sciencedirect.com/science/article/pii/S0092867407004618#; Bowman et al., 2007 ). The article has concise information on the origin and evolution of plant groups, including helpful graphics (Figure 2). Of course, plants were classified and subdivided long before DNA analysis was possible. The Encyclopedia of Earth (EOE) is a good website for exploring biological diversity and has an article on plants (www.eoearth.org/view/article/155261) that lays out the major plant groups and their characteristics. It states that there are more than 400,000 described species, a fraction of the estimated total number.Open in a separate windowFigure 2.Genomic analysis has illuminated the relationship among the many species of plants, as illustrated in this phylogeny of three major plant groups from Bowman et al. (2007 , p. 129).The venerable Kew Gardens has an excellent website (Figure 3) that includes extensive pages under the tab Science and Conservation (www.kew.org/science-conservation). It is a beautifully organized website for exploring plant diversity and burrowing into the science of plants, and includes an excellent blog. Ever wonder how many different kinds of flowers there are? You can find out by visiting their feature titled, “How Many Flowering Plants Are There in the World?” There is an interesting video feature on coffee, which describes how only two species out of more than a hundred have come to dominate coffee production for drinking. As the monoculture in Ireland led to the potato blight, a lack of genetic diversity in today''s coffee plants is threatening the world''s coffee supply with the onset of climate change. The possibility of life without coffee is a call to action if ever I have heard one.Open in a separate windowFigure 3.Kew Gardens has a large and informative website that should appeal to gardeners and flower lovers, as well as more serious botanists and ecologists.Classification of plants is challenging for students and teachers alike. Perhaps understandable, given that plants constitute an entire kingdom of life. For an overview, have students read the EOE article as well as the Bowman Cell article to appreciate the enormity and diversity of the organisms we call plants. The EOE article is reproduced on the Encyclopedia of Life website (http://eol.org/info/449), an excellent context for further exploration of diverse plant species. As we probe the topic of plant behavior, the examples will be drawn from the vascular plants that include the many familiar plants commonly called trees, shrubs, flowers, vegetables, and weeds.Plants do respond to changes in their environment, but is it fruitful or scientifically valid to say that they have behavior? They lack muscles and nerves, do not have mouths or digestive systems, and are often literally rooted in place. A growing number of plant biologists have embraced the term behavior, as demonstrated by the journal devoted to the subject, Plant Behavior. Their resources page (www.plantbehavior.org/resources.html) is a good place to get oriented to the field.As in so many things, Darwin anticipated important questions concerning the movement of plants, despite the difficulties in observing plant behavior, and in 1880 he published The Power of Movement in Plants. The Darwin Correspondence Project website has a good treatment of Darwin''s work on plants, with interesting anecdotes relating to how he collaborated with his son Francis on this work late in his career (www.darwinproject.ac.uk/power-of-movement-in-plants). You can download Chapter 9 of the book and some of the correspondence between Darwin and his son. The entire book is available at http://darwin-online.org.uk/content/frameset?itemID=F1325&viewtype=text&pageseq=1, or in various e-reader formats at the Project Gutenberg website (http://www.gutenberg.org/ebooks/5605). The PBS NOVA website, has a feature covering several of Darwin''s “predictions,” including one in which he noted the importance of plant and animal interactions. He famously predicted that a Madagascar orchid (Angraecum sesquipedale), which has a long narrow passage to its nectar stash, must have a long-tongued pollinator. In 1903, biologists identified the giant hawkmoth, with a 12-inch-long proboscis, as the pollinator predicted by Darwin (www.pbs.org/wgbh/nova/id/pred-nf.html).Darwin recognized that plants mostly do things on a timescale that is hard for us to observe, so he devised clever ways to record their movements. Placing a plant behind a pane of glass, he marked the plant''s position on the glass over time using a stationary reference grid placed behind the plant. Darwin transferred the drawing to a sheet of paper before cleaning the glass for the next experiment (Figure 4). By varying the distance between the plant, the reference points, and the glass, he magnified apparent distances to detect even small plant movements over periods as short as minutes. High-definition time-lapse photography and other modern techniques have extended Darwin''s observations in some compelling directions.Open in a separate windowFigure 4.One of Darwin''s drawings that can be found on the Darwin Correspondence Project Web pages devoted to his book The Power of Movement in Plants. For this figure, the position of the cotyledons of a Brassica was marked on a glass plate about every 30 min over a period of more than 10 h.A recent episode of the PBS Nature series, “What Plants Talk About,” epitomizes the increased interest in plant behavior and, unfortunately, some of the hyperbole associated with the field. The time-lapse video sequences and associated science are fascinating, and the entire program can be viewed on the PBS website at http://video.pbs.org/video/2338524490. The home page for the program (Figure 5; www.pbs.org/wnet/nature/episodes/what-plants-talk-about/introduction/8228) has two short video clips that are interesting. The video titled “Dodder Vine Sniffs Out Its Prey” is nicely filmed and features some interesting experiments involving plant signaling. It might be instructive to ask students to respond to the vocabulary used in the narration, which unfortunately tries to impart intent and mindfulness to the plant''s activities, and to make sensible experimental results somehow seem shocking. The “Plant Self-Defense” video is a compelling “poison pill” story that needs no narrative embellishment. A plant responds to caterpillars feeding on it by producing a substance that tags them for increased attention from predators. Increased predation reduces the number of caterpillars feeding on the plants. The story offers a remarkable series of complex interactions and evolutionary adaptations. Another documentary, In the Mind of Plants (www.youtube.com/watch?v=HU859ziUoPc), was originally produced in French. Perhaps some experimental interpretations were mangled in translation, but the camera work is consistently excellent.Open in a separate windowFigure 5.The Nature pages of the PBS website have video clips and a short article, as well as the entire hour-long program “What Plants Talk About.” The program features fantastic camera work and solid science, but some questionable narration.Skepticism is part and parcel of scientific thinking, but particular caution may be warranted in the field of plant behavior because of the 1970s book and documentary called The Secret Life of Plants (www.youtube.com/watch?v=sGl4btrsiHk). The Secret Life of Plants was a sensation at the time and was largely responsible for the persistent myths that talking to your plants makes them healthier, that plants have auras, and that plants grow better when played classical music rather than rock. While the program woke people up to the notion that plants indeed do fascinating things, the conclusions based on bad science or no science at all were in the end more destructive than helpful to this aspect of plant science. Michael Pollan, author of The Botany of Desire and other excellent plant books, addresses some of the controversy that dogs the field of plant behavior in an interview on the public radio program Science Friday (http://sciencefriday.com/segment/01/03/2014/can-plants-think.html). His article “The Intelligent Plant” in the New Yorker (www.newyorker.com/reporting/2013/12/23/131223fa_fact_pollan?currentPage=all), covers similar ground.The excellently understated Plants in Motion website (http://plantsinmotion.bio.indiana.edu/plantmotion) is a welcome antidote to some of the filmic excesses. The site features dozens of low-definition, time-lapse videos of plants moving, accompanied by straightforward explanations of the experimental conditions and some background on the plants. The lack of narration conveys a refreshing cinema verité quality, and you can choose your own music to play while you watch. Highlights include corn shoots growing toward a light bulb, the rapid response of a mimosa plant to a flame, vines twining, and pumpkins plumping at night. You may have driven past a field of sunflowers and heard the remark that the heads follow the sun, but that is a partial truth. The young buds of the early plants do track the sun, but once they bloom, the tall plants stiffen and every head in the field permanently faces … east! The creators of Plants in Motion curated an exhibit at the Chicago Botanic Gardens called sLowlife (Figure 6). The accompanying video and “essay” (http://plantsinmotion.bio.indiana.edu/usbg/toc.htm) are excellent, featuring many interesting aspects of plant biology.Open in a separate windowFigure 6.sLowlife is an evocative multimedia essay designed to accompany an exhibit installed at the Chicago Botanic Gardens. It features text and video that reveal interesting aspects of plant biology.High-definition time-lapse photography is far from the only tool available to reveal hard-to-observe activities of plants. Greg Asner and colleagues at the Carnegie Airborne Observatory are using informatics to study the dynamic lives of plants at the community ecology level. The Airborne Observatory uses several impressive computer- and laser-enabled techniques (http://cao.stanford.edu/?page=cao_systems) to scan the landscape at the resolution of single leaves on trees and in modalities that can yield information at the molecular level. These techniques can yield insights into how forests respond to heat or water stress or the introduction of a new species. The site has a gallery of projects that are best started at this page: http://cao.stanford.edu/?page=research&pag=5. Here, they are documenting the effect of the Amazon megadrought on the rain forest. The very simple navigation at the top right consists of 15 numbered squares for the different projects. Each project is worth paging through to understand how versatile these aerial-mapping techniques are. They also have six buttons of video pages (http://cao.stanford.edu/?page=videos) that give you a feel for what it might be like to be in the air while collecting the data (Figure 7).Open in a separate windowFigure 7.The Carnegie Airborne Observatory is a flying lab that can collect real-time aerial data on forests at resolutions smaller than a single leaf on a tree.If this Feature seems to have been too conservative about whether plants have behavior, visit the LINV blog (www.linv.org/blog/category/plant-behavior) of the International Laboratory for Plant Neurobiology. The term “plant neurobiology” may be going too far, but the website presents some interesting science. Another fascinating dimension of plant “behavior” is seed dispersal, from seeds that can burrow, to seeds that “fly,” to seeds that are shot like bullets. A couple of websites have some good information and photos of the myriad designs that have evolved to take advantage of air currents for seed dispersal; see http://waynesword.palomar.edu/plfeb99.htm and http://theseedsite.co.uk/sdwind.html. The previously mentioned PBS Nature series also produced a program on seeds, “The Seedy Side of Plants,” which you can view at www.pbs.org/wnet/nature/episodes/the-seedy-side-of-plants/introduction/1268. ChloroFilms, a worldwide competition for plant videos, is now in its fourth season, with some really good videos (www.chlorofilms.org). If you love plants, work with plants, or have insights into plant biology, you should consider submitting a video!  相似文献   

5.
This feature is designed to point CBE—Life Sciences Education readers to current articles of interest in life sciences education as well as more general and noteworthy publications in education research.This feature is designed to point CBE—Life Sciences Education readers to current articles of interest in life sciences education as well as more general and noteworthy publications in education research. URLs are provided for the abstracts or full text of articles. For articles listed as “Abstract available,” full text may be accessible at the indicated URL for readers whose institutions subscribe to the corresponding journal.1. Bush SD, Pelaez NJ, Rudd JA, Stevens MT, Tanner KD, Williams KS (2013). Widespread distribution and unexpected variation among science faculty with education specialties (SFES) across the United States. Proc Natl Acad Sci USA 110, 7170–7175.[Available at: www.pnas.org/content/110/18/7170.full.pdf+html?sid=f2823860-1fef-422c-b861-adfe8d82cef5]College and university basic science departments are taking an increasingly active role in innovating and improving science education and are hiring science faculty with education specialties (SFES) to reflect this emphasis. This paper describes a nationwide survey of these faculty at private and public degree-granting institutions. The authors assert that this is the first such analysis undertaken, despite the apparent importance of SFES at many, if not most, higher education institutions. It expands on earlier work summarizing survey results from SFES used in the California state university system (Bush et al., 2011 ).The methods incorporated a nationwide outreach that invited self-identified SFES to complete an anonymous, online survey. SFES are described as those “specifically hired in science departments to specialize in science education beyond typical faculty teaching duties” or “who have transitioned after their initial hire to a role as a faculty member focused on issues in science education beyond typical faculty teaching duties.” Two hundred eighty-nine individuals representing all major types of institutions of higher education completed the 95-question, face-validated instrument. Slightly more than half were female (52.9%), and 95.5% were white. There is extensive supporting information, including the survey instrument, appended to the article.Key findings are multiple. First, but not surprisingly, SFES are a national, widespread, and growing phenomenon. About half were hired since the year 2000 (the survey was completed in 2011). Interestingly, although 72.7% were in tenured or tenure-track positions, most did not have tenure before adopting SFES roles, suggesting that such roles are not, by themselves, an impediment to achieving tenure. A second key finding was that SFES differed significantly more between institutional types than between science disciplines. For example, SFES respondents at PhD-granting institutions were less likely to occupy tenure-track positions than those at MS-granting institutions and primarily undergraduate institutions (PUIs). Also, SFES at PhD institutions reported spending more time on teaching and less on research than their non-SFES peers. This may be influenced, of course, by the probability that fewer faculty at MS and PUI institutions have research as a core responsibility. The pattern is complex, however, because all SFES at all types of institutions listed teaching, service, and research as professional activities. SFES did report that they were much more heavily engaged in service activities than their non-SFES peers across all three types of institutions. A significantly higher proportion of SFES respondents at MS-granting institutions had formal science education training (60.9%), as compared with those at PhD-granting institutions (39.3%) or PUIs (34.8%).A third finding dealt with success of SFES in obtaining funding for science education research, with funding success defined as cumulatively obtaining $100,000 or more in their current positions. Interestingly, the factors that most strongly correlated statistically with funding success were 1) occupying a tenure-track position, 2) employment at a PhD-granting institution, and 3) having also obtained funding for basic science research. Not correlated were disciplinary field and, surprisingly, formal science education training.Noting that MS-granting institutions show the highest proportions of SFES who are tenured or tenure-track, who are higher ranked, who are trained in science education, and who have professional expectations aligned with those of their non-SFES peers, the authors suggest that these institutions are in the vanguard of developing science education as an independent discipline, similar to ecology or organic chemistry. They also point out that SFES at PhD institutions appear to be a different subset, occupying primarily non–tenure track, teaching positions. To the extent that more science education research funding is being awarded to these latter SFES, who occupy less enfranchised roles within their departments, the authors suggest the possibility that such funding may not substantially improve science education at these institutions. However, the authors make it clear that the implications of their findings merit more careful examination and discussion.2. Opfer JE, Nehm RH, Ha M (2012). Cognitive foundations for science assessment design: knowing what students know about evolution. J Res Sci Teach 49, 744–777.[Abstract available: http://onlinelibrary.wiley.com/doi/10.1002/tea.21028/abstract]The authors previously published an article (Nehm et al., 2012) documenting a new instrument (more specifically, a short-answer diagnostic test), Assessing Contextual Reasoning about Natural Selection (ACORNS). This article describes how cognitive principles were used in designing the theoretical framework of ACORNS. In particular, the authors attempted to follow up on the premise of a National Research Council (2001) report on educational assessment that use of research-based, cognitive models for student learning could improve the design of items used to measure students’ conceptual understandings.In applying this recommendation to design of the ACORNS, the authors were guided by four principles for assessing the progression from novice to expert in using core concepts of natural selection to explain and discuss the process of evolutionary change. The items in ACORNS are designed to assess whether, in moving toward expertise, individuals 1) use core concepts for facilitation of long-term recall; 2) continue to hold naïve ideas coexistent with more scientifically normative ones; 3) offer explanations centered around mechanistic rather than teleological causes; and 4) can use generalizations (abstract knowledge) to guide reasoning, rather than focusing on specifics or less-relevant surface features. Thus, these items prioritize recall over recognition, detect students’ use of causal features of natural selection, test for coexistence of normative and naïve conceptions, and assess students’ focus on surface features when offering explanations.The paper provides an illustrative set of four sample items, each of which describes an evolutionary change scenario with different surface features (familiar vs. unfamiliar taxa; plants vs. animals) and then prompts respondents to write explanations for how the change occurred. To evaluate the ability of items to detect gradations in expertise, the authors enlisted the participation of 320 students enrolled in an introductory biology sequence. Students’ written explanations for each of the four items were independently coded by two expert scorers for presence of core concepts and cognitive biases (deviations from scientifically normative ideas and causal reasoning). Indices were calculated to determine the frequency, diversity, and coherence of students’ concept usage. The authors also compared the students’ grades in a subsequent evolutionary biology course to determine whether the use of core concepts and cognitive biases in their ACORNS explanations could successfully predict future performance.Evidence from these qualitative and quantitative data analyses argued that the items were consistent with the cognitive model and four guiding principles used in their design, and that the assessment could successfully predict students’ level of academic achievement in subsequent study of evolutionary biology. The authors conclude by offering examples of student explanations to highlight the utility of this cognitive model for designing assessment items that document students’ progress toward expertise.3. Sampson V, Enderle P, Grooms J (2013). Development and initial validation of the Beliefs about Reformed Science Teaching and Learning (BARSTL) questionnaire. School Sci Math 113, 3–15.[Available: http://onlinelibrary.wiley.com/doi/10.1111/j.1949-8594.2013.00175.x/full]The authors report on the development of a Beliefs about Reformed Science Teaching and Learning (BARSTL) instrument (questionnaire), designed to map teachers’ beliefs along a continuum from traditional to reform-minded. The authors define reformed views of science teaching and learning as being those that are consistent with constructivist philosophies. That is, as quoted from Driver et al. (1994 , p. 5), views that stem from the basic assumption that “knowledge is not transmitted directly from one knower to another, but is actively built up by the learner” by adjusting current understandings (and associated rules and mental models) to accommodate and make sense of new information and experiences.The basic premise for the instrument development posed by the authors is that teachers’ beliefs about the nature of science and of the teaching and learning of science serve as a filter for, and thus strongly influence how they enact, reform-based curricula in their classrooms. They cite a study from a high school physics setting (Feldman, 2002 ) to illustrate the impact that teachers’ differing beliefs can have on the ways in which they incorporate the same reform-based curriculum into their courses. They contend that, because educational reform efforts “privilege” constructivist views of teaching and learning, the BARSTL instrument could inform design of teacher education and professional development by monitoring the extent to which the experiences they offer are effective in shifting teachers’ beliefs toward the more constructivist end of the continuum.The BARTSL questionnaire described in the article has four subscales, with eight items per subscale. The four subscales are: a) how people learn about science; b) lesson design and implementation; c) characteristics of teachers and the learning environment; and d) the nature of the science curriculum. In each subscale, four of the items were designed to be aligned with reformed perspectives on science teaching and learning, and four to have a traditional perspective. Respondents indicate the extent to which they agree with the item statements on a 4-point Likert scale. In scoring the responses, strong agreement with a reform-based item is assigned a score of 4 and strong disagreement a score of 1; scores for traditional items were assigned on a reverse scale (e.g., 1 for strong agreement). A more extensive characterization of the subscales is provided in the article, along with all of the instrument items (see Appendix).The article describes the seven-step process and associated analyses used to, in the words of the authors, “assess the degree to which the BARTSL instrument has accurately translated the construct, reformed beliefs about science teaching, into an operationalization.” The steps include: 1) defining the specific constructs (concepts that can be used to explain related phenomena) that the instrument would measure; 2) developing instrument items; 3) evaluating items for clarity and comprehensibility; 4) evaluating construct and content validity of the items and subscales; 5) a first round of evaluation of the instrument; 6) item and instrument revision; and 7) a second evaluation of validity and reliability (the extent to which the instrument yields the same results on repetition). Step 3 was accomplished by science education doctoral students who reviewed the items and provided feedback, and step 4 with assistance from a seven-person panel composed of science education faculty and doctoral students. Administration of the instrument to 104 elementary teacher education majors (ETEs) enrolled in a teaching method course was used to evaluate the first draft of the instrument and identify items for inclusion in the final instrument. The instrument was administered to a separate population of 146 ETEs in step 7.The authors used two estimates of internal consistency, a Spearman-Brown corrected correlation and coefficient alpha, to assess the reliability of the instrument; the resulting values were 0.80 and 0.77, respectively, interpreted as being indicative of satisfactory internal consistency. Content validity, defined by the authors as the degree to which the sample of items measures what the instrument was designed to measure, was assessed by a panel of experts who reviewed the items within each of the four subscales. The experts concluded that items that were designed to be consistent with reformed and traditional perspectives were in fact consistent and were evenly distributed throughout the instrument. To evaluate construct validity (which was defined as the instrument''s “theoretical integrity”), the authors performed a correlation analysis on the four subscales to examine the extent to which each could predict the final overall score on the instrument and thus be viewed as a single construct of reformed beliefs. They found that each of the subscales was a good predictor of overall score. Finally, they performed an exploratory factor analysis and additional follow-up analyses to determine whether the four subscales measure four dimensions of reformed beliefs and to ensure that items were appropriately distributed among the subscales. In general, the authors contend that the results of these analyses indicated good content and construct validity.The authors conclude by pointing out that BARTSL scores could be used for quantitative comparisons of teachers’ beliefs and stances about reform-minded science teaching and learning and for following changes over time. However, they recommend BARTSL scores not be used to infer a given level of reform-mindedness and are best used in combination with other data-collection techniques, such as observations and interviews.4. Meredith DC, Bolker JA (2012). Rounding off the cow: challenges and successes in an interdisciplinary physics course for life sciences students. Am J Phys 80, 913–922.[Abstract available at: http://ajp.aapt.org/resource/1/ajpias/v80/i10/p913_s1?isAuthorized=no]There is a well-recognized need to rethink and reform the way physics is taught to students in the life sciences, to evaluate those efforts, and to communicate the results to the education community. This paper describes a multiyear effort at the University of New Hampshire by faculties in physics and biological sciences to transform an introductory physics course populated mainly by biology students into an explicitly interdisciplinary course designed to meet students’ needs.The context was that of a large-enrollment (250–320 students), two-semester Introductory Physics for Life Science Students (IPLS) course; students attend one of two lecture sections that meet three times per week and one laboratory session per week. The IPLS course was developed and cotaught by the authors, with a goal of having “students understand how and why physics is important to biology at levels from ecology and evolution through organismal form and function, to instrumentation.” The selection of topics was drastically modified from that of a traditional physics course, with some time-honored topics omitted or de-emphasized (e.g., projectile motion, relativity), and others thought to be more relevant to biology introduced or emphasized (e.g., fluids, dynamics). In addition, several themes not always emphasized in a traditional physics course but important in understanding life processes were woven through the IPLS course: scaling, estimation, and gradient-driven flows.It is well recognized that life sciences students need to strengthen their quantitative reasoning skills. To address their students’ needs in this area, the instructors ensured that online tutorials were available to students, mathematical proofs that the students are not expected use were de-emphasized, and Modeling Instruction labs were incorporated that require students to model their own data with an equation and compose a verbal link between their equations and the physical world.Student learning outcomes were assessed through the use of the Colorado Learning Attitudes about Science Survey (CLASS), which measures students’ personal epistemologies of science by their responses on a Likert-scale survey. These data were supplemented by locally developed, open-ended surveys and Likert-scale surveys to gauge students’ appreciation for the role of physics in biology. Students’ conceptual understanding was evaluated using the Force and Motion Concept Evaluation (FCME) and Test of Understanding Graphs in Kinematics (TUG-K), as well as locally developed, open-ended physics problems that probed students’ understanding in the context of biology-relevant applications and whether their understanding of physics was evident in their use of mathematics.The results broadly supported the efficacy of the authors’ approaches in many respects. More than 80% of the students very strongly or strongly agreed with the statement “I found the biological applications interesting,” and almost 60% of the students very strongly or strongly agreed with the statements “I found the biological applications relevant to my other courses and/or my planned career” and “I found the biological applications helped me understand the physics.” Students were also broadly able to integrate physics into their understanding of living systems. Examples of questions that students addressed include one that asked students to evaluate the forces on animals living in water versus those on land. Ninety-one percent of the students were able to describe at least one key difference between motion in air and water. Gains in the TUG-K score averaged 33.5% across the 4 yr of the course offering and were consistent across items. However, the positive attitudes about biology applications in physics were not associated with gains in areas of conceptual understanding measured by the FCME instrument. These gains were more mixed than those from the TUG-K and dependent on the concept being evaluated, with values as low as 15% for some concepts and an average gain on all items of 24%. Overall, the gains on the two instruments designed to measure physics understanding were described by the authors as being “modest at best,” particularly in the case of the FCME, given that reported national averages for reformed courses for this instrument range from 33 to 93%.The authors summarize by identifying considerations they think are essential to design and implementation of a IPLS-like course: 1) the need to streamline the coverage of course topics to emphasize those that are truly aligned with the needs of life sciences majors; 2) the importance of drawing from the research literature for evidence-based strategies to motivate students and aid in their development of problem-solving skills; 3) taking the time to foster collaborations with biologists who will reinforce the physics principles in their teaching of biology courses; and 4) considering the potential constraints and limitations to teaching across disciplinary boundaries and beginning to strategize ways around them and build models for sustainability. The irony of this last recommendation is that the authors report having suspended the teaching of IPLS at their institution due to resource constraints. They recommend that institutions claiming to value interdisciplinary collaboration need to find innovative ways to reward and acknowledge such collaborations, because “external calls for change resonate with our own conviction that we can do better than the traditional introductory course to help life science students learn and appreciate physics.”I invite readers to suggest current themes or articles of interest in life science education, as well as influential papers published in the more distant past or in the broader field of education research, to be featured in Current Insights. Please send any suggestions to Deborah Allen (ude.ledu@nellaed).  相似文献   

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The National Institutes of Health publishes a series of science curriculum supplements for K–12 education that are available from their Web site free of charge (http://science.education.nih.gov/supplements). In this feature, we review two of the high school supplements, Human Genetic Variation and Cell Biology and Cancer. Overall, we find that they are both excellent resources that engage students in learning science content while emphasizing the impact of scientific breakthroughs on personal and public health. In this review, we highlight the many strong features of the curricula and point out instances in which teachers may wish to seek out supplemental, updated information.  相似文献   

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A response to Maskiewicz and Lineback''s essay in the September 2013 issue of CBE-Life Sciences Education.Dear Editor:Maskiewicz and Lineback (2013) have written a provocative essay about how the term misconceptions is used in biology education and the learning sciences in general. Their historical perspective highlights the logic and utility of the constructivist theory of learning. They emphasize that students’ preliminary ideas are resources to be built upon, not errors to be eradicated. Furthermore, Maskiewicz and Lineback argue that the term misconception has been largely abandoned by educational researchers, because it is not consistent with constructivist theory. Instead, they conclude, members of the biology education community should speak of preconceptions, naïve conceptions, commonsense conceptions, or alternative conceptions.We respectfully disagree. Our objections encompass both the semantics of the term misconception and the more general issue of constructivist theory and practice. We now address each of these in turn. (For additional discussion, please see Leonard, Andrews, and Kalinowski , “Misconceptions Yesterday, Today, and Tomorrow,” CBE—Life Sciences Education [LSE], in press, 2014.)Is misconception suitable for use in scholarly discussions? The answer depends partly on the intended audience. We avoid using the term misconception with students, because it could be perceived as pejorative. However, connotations of disapproval are less of a concern for the primary audience of LSE and similar journals, that is, learning scientists, discipline-based education researchers, and classroom teachers.An additional consideration is whether misconception is still used in learning sciences outside biology education. Maskiewicz and Lineback claim that misconception is rarely used in journals such as Cognition and Instruction, Journal of the Learning Sciences, Journal of Research in Science Teaching, and Science Education, yet the term appears in about a quarter of the articles published by these journals in 2013 (National Research Council, 2012 ).

Table 1.

Use of the term misconception in selected education research journals in 2013
Journal (total articles published in 2013a)Articles using misconception (“nondisapproving” articles/total articles)Articles using other terms
LSE (59)23/24Alternative conception (4)
Commonsense conception (2)
Naïve conception (1)
Preconception (4)
Cognition and Instruction (16)3/3None
Journal of the Learning Sciences (17)4/4Commonsense science knowledge (1)
Naïve conception (1)
Prior conception (1)
Journal of Research in Science Teaching (49)11/13Commonsense idea (1)
Naïve conception (1)
Preconception (5)
Science Education (36)10/11Naïve conception (1)
Open in a separate windowaAs of November 25, 2013. Does not include very short editorials, commentaries, corrections, or prepublication online versions.A final consideration is whether any of the possible alternatives to misconception are preferable. We feel that the alternatives suggested by Maskiewicz and Lineback are problematic in their own ways. For example, naïve conception sounds more strongly pejorative to us than misconception. Naïve conception and preconception also imply that conceptual challenges occur only at the very beginning stages of learning, even though multiple rounds of conceptual revisions are sometimes necessary (e.g., see figure 1 of Andrews et al., 2012 ) as students move through learning progressions. Moreover, the terms preferred by Maskiewicz and Lineback are used infrequently (Smith et al. (1993) that they object to statements that misconceptions should be actively confronted, challenged, overcome, corrected, and/or replaced (Smith et al. (1993) argue on theoretical grounds that confrontation does not allow refinement of students’ pre-existing, imperfect ideas; instead, the students must simply choose among discrete prepackaged ideas. From Maskiewicz and Lineback''s perspective, the papers listed in Maskiewicz and Lineback (2013) as using outdated views of misconceptionsa
ArticleExample of constructivist languageExample of language suggesting confrontation
Andrews et al., 2011 “Constructivist theory argues that individuals construct new understanding based on what they already know and believe.… We can expect students to retain serious misconceptions if instruction is not specifically designed to elicit and address the prior knowledge students bring to class” (p. 400).Instructors were scored for “explaining to students why misconceptions were incorrect” and “making a substantial effort toward correcting misconceptions” (p. 399). “Misconceptions must be confronted before students can learn natural selection” (p. 399). “Instructors need to elicit misconceptions, create situations that challenge misconceptions.” (p. 403).
Baumler et al., 2012 “The last pair [of students]''s response invoked introns, an informative answer, in that it revealed a misconception grounded in a basic understanding of the Central Dogma” (p. 89; acknowledges students’ useful prior knowledge).No relevant text found
Cox-Paulson et al., 2012 No relevant text foundThis paper barely mentions misconceptions, but cites sources (Phillips et al., 2008 ; Robertson and Phillips, 2008 ) that refer to “exposing,” “uncovering,” and “correcting” misconceptions.
Crowther, 2012 “Prewritten songs may explain concepts in new ways that clash with students’ mental models and force revision of those models” (p. 28; emphasis added).“Songs can be particularly useful for countering … conceptual misunderstandings.… Prewritten songs may explain concepts in new ways that clash with students’ mental models and force revision of those models” (p. 28).
Kalinowski et al., 2010 “Several different instructional approaches for helping students to change misconceptions … agree that instructors must take students’ prior knowledge into account and help students integrate new knowledge with their existing knowledge” (p. 88).“One strategy for correcting misconceptions is to challenge them directly by ‘creating cognitive conflict,’ presenting students with new ideas that conflict with their pre-existing ideas about a phenomenon… In addition, study of multiple examples increases the chance of students identifying and overcoming persistent misconceptions” (p. 89).
Open in a separate windowaWhile these papers do not adhere to Smith et al.''s (1993) version of constructivism, they do adhere to the constructivist approach that advocates cognitive dissonance.Our own stance differs from that of Maskiewicz and Lineback, reflecting a lack of consensus within constructivist theory. We agree with those who argue that, not only are confrontations compatible with constructivist learning, they are a central part of it (e.g., Gilbert and Watts, 1983 ; Hammer, 1996 ). We note that Baviskar et al. (2009) list “creating cognitive dissonance” as one of the four main tenets of constructivist teaching. Their work is consistent with research showing that focusing students on conflicting ideas improves understanding more than approaches that do not highlight conflicts (e.g., Kowalski and Taylor, 2009 ; Gadgil et al., 2012 ). Similarly, the Discipline-Based Education Research report (National Research Council, 2012 , p. 70) advocates “bridging analogies,” a form of confrontation, to guide students toward more accurate ways of thinking. Therefore, we do not share Maskiewicz and Lineback''s concerns about the papers listed in Price, 2012 ). We embrace collegial disagreement.Maskiewicz and Lineback imply that labeling students’ ideas as misconceptions essentially classifies these ideas as either right or wrong, with no intermediate stages for constructivist refinement. In fact, a primary goal of creating concept inventories, which use the term misconception profusely (e.g., Morris et al., 2012 ; Prince et al., 2012 ), is to demonstrate that learning is a complex composite of scientifically valid and invalid ideas (e.g., Andrews et al., 2012 ). A researcher or instructor who uses the word misconceptions can agree wholeheartedly with Maskiewicz and Lineback''s point that misconceptions can be a good starting point from which to develop expertise.As we have seen, misconception is itself fraught with misconceptions. The term now embodies the evolution of our understanding of how people learn. We support the continued use of the term, agreeing with Maskiewicz and Lineback that authors should define it carefully. For example, in our own work, we define misconceptions as inaccurate ideas that can predate or emerge from instruction (e.g., Andrews et al., 2012 ). We encourage instructors to view misconceptions as opportunities for cognitive dissonance that students encounter as they progress in their learning.  相似文献   

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This edited volume of essays presents a countermainstream view against genetic underpinnings for cancer, behavior, and psychiatric conditions.This edited volume is a project from the Council of Responsible Genetics, a private organization based in Cambridge, Massachusetts, whose mission, as stated on its website, includes as one of several goals to “expose oversimplified and distorted scientific claims regarding the role of genetics in human disease, development and behavior.” This book represents such an effort. Editors Krimsky and Gruber are chair and president/executive director, respectively, of the organization and appear to have solicited contributions to the book from affiliates and other colleagues. Fewer than half of the 16 chapters are written by active laboratory scientists, however, and as a result, the book suffers from arguments clouded by imprecise use of terminology and preconceptions about genes and their functions. One might consider this book, or parts thereof, for an advanced undergraduate genetics class in which positions counter to the mainstream scientific view are presented and evaluated, and in which students are challenged to critically assess the quality of support for all arguments.The general theme of this book is to question the role of genes (and reproducible molecular mechanisms, more broadly) in cancer, behavior, psychiatric disorders, evolution, and other phenomena. One chapter promotes the tissue organization field theory (TOFT) against the somatic mutation theory of cancer. TOFT was proposed by the chapter authors in 2011 (Soto and Sonnenschein, 2011 ) but has not found traction and has garnered little attention beyond an initial refutation (Vaux, 2011 ). The authors assert that cancer is a disease of development and tissue repair primarily from environmental exposures and independent of genetic changes. Most cancer researchers agree that environmental factors can trigger cell growth but that ensuing mutations complete the picture in the genesis of malignancies. This chapter would be a good starting point from which one could assign students to explore papers cited in the Cancer Genome Atlas database, a growing resource compiling cancer genome data and subsequent validation in other systems of the effects of mutations found. In another chapter, a nonscientist author asserts that “in only a small percentage of cases are genes notable contributors to breast cancer,” implying imprecisely that only rare inherited cancer predisposition is genetic, when in fact cancer stemming from somatic mutations is also gene based. To assert that cancer stems only from environmental effects, to the exclusion of genes, overlooks the intertwining of the two arenas—radiation induces somatic mutations, for example, and estrogen mimics trigger cell division, which sets the stage for additional new mutations during DNA replication. Open in a separate windowOther sections of the book argue a lack of evidence for genetic influence on behaviors and psychiatric conditions. One chapter centers on several refuted ideas of biology and behavior (for example XYY and monoamine oxidase genotypes associated with aggression), with the intended implication that all other biological connections to behavior must be suspect. A chapter on autism accepts but downplays a partial role of genetics in the disorder, while emphasizing environmental exposures. Students exploring this topic could examine the growing literature on de novo mutations found in autism patients (Huguet et al., 2013 ), among other autism studies, to see how interlocking causes of the disorder might best explained by the available data. In the context of disorders such as schizophrenia, the book does not acknowledge or address the literature reporting genetic associations with psychiatric predispositions. In a troubling instance, a cited reference is misrepresented as refuting a genetic connection to schizophrenia; the reference in question (Collins et al., 2012 ) actually reports genome-wide association studies showing linkage of schizophrenia to particular loci (just not to the genes originally suspected). The same research group the previous month reported copy number variations associated with schizophrenia (Kirov et al., 2012 ), but this finding was not cited. Psychiatric genetics is a rich area for students to explore, and the contrarian viewpoint of the book can provide a starting point to trigger students’ delving into the literature.Genetic Explanations: Sense and Nonsense includes two chapters with assertions counter to the neo-Darwinian synthesis of evolution. One claims, fairly misleadingly, that “a growing number of evolutionary biologists … believe that macroevolution was the result of mechanisms other than natural selection.” Another states that “not genomic DNA but epigenetic environmental influences … overwhelmingly affect our health and well being.” The idea that gene regulation via environmental and epigenetic effects is somehow not reducible to genes (and that genes are therefore not central to evolution) would be an interesting subject for students to explore in the literature to see what the data actually support.This book is recommended only for use in advanced classes centered on weighing evidence and dissecting arguments in scientific controversies. The book''s countermainstream assertion of a lack of significant genetic connection to cancer, autism, schizophrenia, and other phenomena provides multiple opportunities for students to explore the scientific literature surrounding such genetic connections.  相似文献   

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Testing within the science classroom is commonly used for both formative and summative assessment purposes to let the student and the instructor gauge progress toward learning goals. Research within cognitive science suggests, however, that testing can also be a learning event. We present summaries of studies that suggest that repeated retrieval can enhance long-term learning in a laboratory setting; various testing formats can promote learning; feedback enhances the benefits of testing; testing can potentiate further study; and benefits of testing are not limited to rote memory. Most of these studies were performed in a laboratory environment, so we also present summaries of experiments suggesting that the benefits of testing can extend to the classroom. Finally, we suggest opportunities that these observations raise for the classroom and for further research.Almost all science classes incorporate testing. Tests are most commonly used as summative assessment tools meant to gauge whether students have achieved the learning objectives of the course. They are sometimes also used as formative assessment tools—often in the form of low-stakes weekly or daily quizzes—to give students and faculty members a sense of students’ progression toward those learning objectives. Occasionally, tests are also used as diagnostic tools, to determine students’ preexisting conceptions or skills relevant to an upcoming subject. Rarely, however, do we think of tests as learning tools. We may acknowledge that testing promotes student learning, but we often attribute this effect to the studying students do to prepare for the test. And yet, one of the most consistent findings in cognitive psychology is that testing leads to increased retention more than studying alone does (Roediger and Butler, 2011 ; Roediger and Pyc, 2012 ). This effect can be enhanced when students receive feedback for failed tests and can be observed for both short-term and long-term retention. There is some evidence that testing not only improves student memory of the tested information but also ability to remember related information. Finally, testing appears to potentiate further study, allowing students to gain more from study periods that follow a test. Given the potential power of testing as a tool to promote learning, we should consider how to incorporate tests into our courses not only to gauge students’ learning, but also to promote that learning (Klionsky, 2008 ).We provide six observations about the effects of testing from the cognitive psychology literature, summarizing key studies that led to these conclusions (see
StudyResearch question(s)ConclusionLength of delay before final testStudy participants
Repeated retrieval enhances long-term retention in a laboratory setting
“Test-enhanced learning: taking memory tests improves long-term retention” (Roediger and Karpicke, 2006a) Is a testing effect observed in educationally relevant conditions? Is the benefit of testing greater than the benefit of restudy? Do multiple tests produce a greater effect than a single test?Testing improved retention significantly more than restudy in delayed tests. Multiple tests provided greater benefit than a single test.Experiment 1: 2 d; 1 wk Experiment 2: 1 wkUndergraduates ages 18–24, Washington University
“Retrieval practice with short-answer, multiple-choice, and hybrid tests” (Smith and Karpicke, 2014) What effect does the type of question presented in retrieval practice have on long-term retention?Retrieval practice with multiple-choice, free-response, and hybrid formats improved students’ performance on a final, delayed test taken 1 wk later when compared with a no-retrieval control. The effect was observed for both questions that required only recall and those that required inference. Hybrid questions provided an advantage when the final test had a short-answer format.1 wkUndergraduates, Purdue University
“Retrieval practice produces more learning that elaborative studying with concept mapping” (Karpicke and Blunt, 2011) What is the effect of retrieval practice on learning relative to elaborative study using a concept map?Students in the retrieval-practice condition had greater gains in meaningful learning compared with those who used elaborative concept mapping as a learning tool.1 wkUndergraduates
Various testing formats can enhance learning
“Retrieval practice with short-answer, multiple-choice, and hybrid tests” (Smith and Karpicke, 2014) See above.See above.See above.See above.
“Test format and corrective feedback modify the effect of testing on long-term retention” (Kang et al., 2007) What effect does the type of question used for retrieval practice have on retention? Does feedback have an effect on retention for different types of questions?When no feedback was given, the difference in long-term retention between short-answer and multiple-choice questions was insignificant. When feedback was provided, short-answer questions were slightly more beneficial.3 dUndergraduates, Washington University psychology subjects’ pool
“The persisting benefits of using multiple-choice tests as learning events” (Little and Bjork, 2012) What effect does question format have on retention of information previously tested and related information not included in retrieval practice?Both cued-recall and multiple-choice questions improved recall compared with the no-test control. However, multiple-choice questions improved recall more than cued-recall questions for information not included in the retrieval practice, both after a 5-min and a 48-h delay.48 hUndergraduates, University of California, Los Angeles
Feedback enhances benefits of testing
“Feedback enhances positive effects and reduces the negative effects of multiple-choice testing” (Butler and Roediger, 2008) What effect does feedback on multiple-choice tests have on long-term retention of information?Feedback improved retention on a final cued-recall test. Delayed feedback resulted in better final performance than immediate feedback, though both showed benefits compared with no feedback. The final test occurred 1 wk after the initial test.1 wkUndergraduate psychology students, Washington University
“Correcting a metacognitive error: feedback increases retention of low-confidence responses” (Butler et al., 2008) What role does feedback play in retrieval practice? Can it correct metacognitive errors as well as memory errors?Both initially correct and incorrect answers were benefited by feedback, but low-confidence answers were most benefited by feedback.5 minUndergraduate psychology students, Washington University
Learning is not limited to rote memory
“Retrieval practice produces more learning than elaborative study with concept mapping” (Karpicke and Blunt, 2011) What is the effect of retrieval practice on learning relative to elaborative study using a concept map? Does retrieval practice improve students’ ability to perform higher-order cognitive activities (i.e., building a concept map) as well as simple recall tasks?Compared with elaborative study using concept mapping, retrieval practice improved students’ performance both on final tests that required short answers and final tests that required concept map production. See also earlier entry for this study.1 wkUndergraduates
“Retrieval practice with short-answer, multiple-choice, and hybrid tests” (Smith and Karpicke, 2014) See above.See above.See above.See above.
“Repeated testing produces superior transfer of learning relative to repeated studying” (Butler, 2010) Does test-enhanced learning promote transfer of facts and concepts from one domain to another?Testing improved retention and increased transfer of information from one domain to another through test questions that required factual or conceptual recall and inferential questions that required transfer.1 wkUndergraduate psychology students, Washington University
Testing potentiates further study
“Pretesting with multiple-choice questions facilitates learning” (Little and Bjork, 2011) Does pretesting using multiple-choice questions improve performance on a later test? Is an effect observed only for pretested information or also for related, previously untested information?A multiple-choice pretest improved performance on a final test, both for information that was included on the pretest and related information.1 wkUndergraduates, University of California, Los Angeles
“The interim test effect: testing prior material can facilitate the learning of new material” (Wissman et al., 2011) Does an interim test over previously learned material improve retention of subsequently learned material?Interim testing improves recall on a final test for information taught before and after the interim test.No delayUndergraduates, Kent State University
The benefits of testing appear to extend to the classroom
“The exam-a-day procedure improves performance in psychology classes” (Leeming, 2002) What effect does a daily exam have on retention at the end of the semester?Students who took a daily exam in an undergraduate psychology class scored higher on a retention test at the end of the course and had higher average grades than students who only took unit tests.One semesterUndergraduates enrolled in Summer term of Introductory Psychology, University of Memphis
“Repeated testing improves long-term retention relative to repeated study: a randomized controlled trial” (Larsen et al., 2009) Does repeated testing improve long-term retention in a real learning environment?In a study with medical residents, repeated testing with feedback improved retention more than repeated study for a final recall test 6 mo later.6 moResidents from Pediatrics and Emergency Medicine programs, Washington University
“Retrieving essential material at the end of lectures improves performance on statistics exams” (Lyle and Crawford, 2011) What effect does daily recall practice using the PUREMEM method have on course exam scores?In an undergraduate psychology course, students using the PUREMEM method had higher exams scores than students taught with traditional lectures, assessed by four noncumulative exams spaced evenly throughout the semester.∼3.5 wkUndergraduates enrolled in either of two consecutive years of Statistics for Psychology, University of Louisville
“Using quizzes to enhance summative-assessment performance in a web-based class: an experimental study” (McDaniel et al., 2012) What effects do online testing resources have on retention of information in an online undergraduate neuroscience course?Both multiple-choice and short-answer quiz questions improved retention and improved scores on the final exam for questions identical to those on the weekly quizzes and those that were related but not identical.15 wkUndergraduates enrolled in Web-based brain and behavior course
“Increasing student success using online quizzing in introductory (majors) biology” (Orr and Foster, 2013) What effect do required pre-exam quizzes have on final exam scores for students in an introductory (major) biology course?Students were required to complete 10 pre-exam quizzes throughout the semester. The scores of students who completed all of the quizzes or none of the quizzes were compared. Students of all abilities who completed all of the pre-exam quizzes had higher average exam scores than those who completed none.One semesterCommunity college students enrolled in an introductory biology course for majors
“Teaching students how to study: a workshop on information processing and self-testing helps students learn” (Stanger-Hall et al., 2011) What effect does a self-testing exercise done in a workshop have on final exam questions covering the same topic used in the workshop?Students who participated in the retrieval-practice workshop performed better on the exam questions related to the material covered in the workshop activity. However, there was no difference in overall performance on the exam between the two groups.10 wkUndergraduate students in a introductory biology class
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Interactions Are Critical     
Christopher W. Beck  Nancy G. Bliwise 《CBE life sciences education》2014,13(3):371-372
Although we agree with Theobold and Freeman (2014) that linear models are the most appropriate way in which to analyze assessment data, we show the importance of testing for interactions between covariates and factors.To the Editor:Recently, Theobald and Freeman (2014) reviewed approaches for measuring student learning gains in science, technology, engineering, and mathematics (STEM) education research. In their article, they highlighted the shortcomings of approaches such as raw change scores, normalized gain scores, normalized change scores, and effect sizes when students are not randomly assigned to classes based on the different pedagogies that are being compared. As an alternative, they propose using linear regression models in which characteristics of students, such as pretest scores, are included as independent variables in addition to treatments. Linear models that include both continuous and categorical independent variables are often termed analysis of covariance (ANCOVA) models. The approach of using ANCOVA to control for differences in students among treatments groups has been suggested previously by Weber (2009) . We largely agree with Theobald and Freeman (2014) and Weber (2009) that ANCOVA models are an appropriate method for situations in which students cannot be randomly assigned to treatments and controls. However, in describing how to implement linear regression models to examine student learning gains, Theobald and Freeman (2014) ignore a fundamental assumption of ANCOVA.ANCOVA assumes homogeneity of slopes (McDonald, 2009 ; Sokal and Rohlf, 2011 ). In other words, the slope of the relationship between the covariate (e.g., pretest score) and the dependent variable (e.g., posttest score) is the same for the treatment group and the control. This assumption is a strict assumption of ANCOVA in that violations of this assumption can result in incorrect conclusions (Engqvist, 2005 ). For example, in Figure 1, both pretest score and treatment have statistically significant main effects in a linear model with only pretest score (F(1, 97) = 25.6, p < 0.001) and treatment (F(1, 97) = 42.6, p < 0.01) as independent variables. Therefore, we would conclude that all students in the class with pedagogical innovation had significantly greater posttest scores than those students in the control class for a given pretest score. Furthermore, we would conclude that the pedagogical innovation led to the same increase in score for all students in the treatment class, independent of their pretest scores. Clearly, neither of these conclusions would be justified.Researchers must first test the assumption of the homogeneity of slopes by including an interaction term (covariate × treatment) in their linear model (McDonald, 2009 ; Weber 2009 ; Sokal and Rohlf, 2011 ). For example, if we measured student achievement in two courses with different instructional approaches in a typical pretest/posttest design, then the interaction between students’ pretest scores and the type of instruction must be considered, because the instruction may have a different effect for high- versus low-achieving students. If multiple covariates are included in the linear model (see Equation 1 in Theobald and Freeman, 2014 ), then interaction terms need to be included for each of the covariates in the model. If the interaction term is statistically significant, this suggests that the relationship between the covariate and the dependent variable is different for each treatment group (F(1, 96) = 25.1, p < 0.001; Figure 1). As a result, the effect of the treatment will depend on the value of the covariate, and universal statements about the effect of the treatment are not appropriate (Engqvist, 2005 ). If the interaction term is not statistically significant, it should be removed from the model and the analysis rerun without the interaction term. Failure to remove an interaction term that was not statistically significant also can lead to an incorrect conclusion (Engqvist, 2005 ). Whether there are statistically significant interactions between the “treatment” and the covariates in the data set used by Theobald and Freeman (2014) is unclear.Open in a separate windowFigure 1.Simulated data to demonstrate heterogeneity of slopes. Pretest values were generated from random normal distributions with mean = 59.8 (SD = 18.1) for the treatment course and mean = 59.3 (SD = 17.0) for the control course, based on values given in Theobald and Freeman (2014) . For the treatment course, posttest values were calculated using the formula posttesti = 80 + 0.1 × pre-testi + Ɛi, where Ɛi was selected from a random normal distribution with mean = 0 (SD = 10). For the control course, posttest values were calculated using the formula posttesti = 42 + 0.5 × pre-testi + Ɛi, where Ɛi was selected from a random normal distribution with mean = 0 (SD = 10). n = 50 for both courses.In addition to being a strict assumption of ANCOVA, testing for homogeneity of slopes in a linear model is important in STEM education research, as slopes are likely heterogeneous for several reasons. First, for many instruments used in STEM education research, high-achieving students score high on the pretest. As a result, their ability to improve is limited due to the ceiling effect, and differences between treatment and control groups in posttest scores are likely to be minimal (Figure 1). In contrast, low-achieving students have a greater opportunity to change their scores between their pretest and posttest. Second, pedagogical innovations are more likely to have a greater impact on the learning of lower-performing students than higher-performing students. For example, Beck and Blumer (2012) found statistically greater gains in student confidence and scientific reasoning skills for students in the lowest quartile as compared with students in the highest quartile on pretest assessments in inquiry-based laboratory courses.Theobald and Freeman (2014, p. 47) note that “regression models can also include interaction terms that test whether the intervention has a differential impact on different types of students.” Yet, we argue that these terms must be included and only should be excluded if they are not statistically significant.  相似文献   

19.
Jo Handelsman     
Laura L. Mays Hoopes 《CBE life sciences education》2009,8(3):165-166

Note from the Editor

Educator Highlights for CBE-LSE show how professors at different kinds of institutions educate students in life sciences with inspiration and panache. If you have a particularly creative teaching portfolio yourself, or if you wish to nominate an inspiring colleague to be profiled, please e-mail Laura Hoopes at lhoopes@pomona.edu.LH: You are deeply involved with the HHMI Teaching Fellows Program at Wisconsin and the Wisconsin Program for Scientific Teaching (Pfund et al., 2009 ), and you''ve coauthored a book about scientific teaching (Handelsman et al., 2006 ). How do you teach people to teach in your summer institutes?Handelsman: The HHMI Graduate Teaching Fellows Program teaches graduate students and postdoctoral fellows to apply theories of learning to classroom practice. The fellows set learning goals and assess whether they''re achieved. It''s theory, then practice.LH: Can you explain a little more about how it works?Handelsman: The program starts with eight weeks of a course, “Teaching Biology” in which the fellows learn about education principles and then practice on each other applying those principles. Then they go on to design their own materials, and finally, in the second semester, use that material in teaching students. In our qualitative and quantitative analysis of their teaching philosophy, we see little change after the first semester. But there is radical improvement after they put their ideas into practice in the second part. People learn by doing.LH: How about a specific example of how the fellows develop materials.Handelsman: There''s a choice of venues, but let''s say one picks the honors biology course. They identify a technical problem, such as explaining Southern, Northern, and Western blotting. Our fellows then develop active-learning materials to address a challenging concept and test them in the classroom, often in multiple sections of a class. They refine and retest them. Another fellow might choose “Microbes Rule,” a course developed by fellows, which teaches about bacteria, viruses, and fungi. That fellow develops learning goals about antibiotic resistance, flu, or contaminated peanut butter, and designs classroom materials to achieve these goals.Open in a separate windowJo Handelsman, HHMI Professor, Department of Bacteriology, University of Wisconsin–Madison, Madison, WI.LH: Do the teaching fellows find the work difficult?Handelsman: It''s a challenge for them to narrow down to a workable subtopic. We work with them to focus on the learning goals, asking “The students will know and be able to do what at the end of this unit?”LH: Did you learn this method of focusing on goals when you were being trained?Handelsman: No, most of us were never taught to consider goals for learning. So in training our fellows, we direct them to focus on that over and over, and ask how their plans relate to the goals. It''s backward design—think about what you want to achieve, then think about how to get there.LH: Assessment is becoming more important at universities and colleges all over the country. How do you teach the fellows to use it?Handelsman: Students design their own instruments. They develop skills to determine whether their goals are being met. We go over the tools with them repeatedly, identify potential downfalls, let them implement, and then review the results to see if they obtained the information needed to determine whether their teaching worked.LH: What kind of questions do they tend to use for assessment?Handelsman: Exam-type questions are important, whether taken as an examination or in a questionnaire. Videos of student presentations with reviewers who score on effectiveness are also useful. We ask how the fellows know if the students understood the material, and how the evidence relates to each of their learning goals.LH: How do they evaluate and incorporate input from past assessment?Handelsman: Before using an instrument for assessment, the fellows develop a rubric to score the quality of the answers. Often they decide to share this rubric with the students. They want to show the students what goal the assessment is addressing, what is an adequate answer, what is an outstanding answer. Then they discuss with their peers how to use this feedback to improve their teaching.LH: I''ve heard faculty members at other places saying that they do lots of assessment but don''t know what to do with it after they are forced to collect the information.Handelsman: I''d suggest that they do less and use it more! Not using assessment results is like designing a new experiment but ignoring your earlier results. If we have the information to improve our teaching, we should use it.LH: A lot of interviews for faculty positions ask for a teaching philosophy. It sounds like your fellows are well-positioned to answer these questions.Handelsman: Yes, they have to write their teaching philosophy several times, discuss it with the other fellows, and rewrite. The fellows have been very successful in obtaining positions.LH: Have you had undergraduate research students?Handelsman: Yes, it''s one of the most important academic activities in which students take part—anything hands-on is good, but undergraduate research is the best because it incorporates inquiry, discovery, real scientific processes. It plays into curiosity. It''s such a rewarding process to watch a student in the research lab! It''s a powerful thing to see them learn and grow into scientists over the course of a semester or two.LH: What motivated you to take on undergraduate research students at the start?Handelsman: I started undergraduate research myself in my first year of college—I walked into a lab and asked to do experiments. The difference between doing research and reading about it is so dramatic. I''ve always assumed that part of the structure of an academic lab is undergraduate involvement. Interestingly, I sometimes give the undergraduates riskier projects than the graduate students, who have more to lose if their projects fail.LH: Thanks for sharing your insights into teaching with CBE-LSE.  相似文献   

20.
Development of a Meiosis Concept Inventory     
Pamela Kalas  Angie O’Neill  Carol Pollock  Gülnur Birol 《CBE life sciences education》2013,12(4):655-664
We have designed, developed, and validated a 17-question Meiosis Concept Inventory (Meiosis CI) to diagnose student misconceptions on meiosis, which is a fundamental concept in genetics. We targeted large introductory biology and genetics courses and used published methodology for question development, which included the validation of questions by student interviews (n = 28), in-class testing of the questions by students (n = 193), and expert (n = 8) consensus on the correct answers. Our item analysis showed that the questions’ difficulty and discrimination indices were in agreement with published recommended standards and discriminated effectively between high- and low-scoring students. We foresee other institutions using the Meiosis CI as both a diagnostic tool and an instrument to assess teaching effectiveness and student progress, and invite instructors to visit http://q4b.biology.ubc.ca for more information.  相似文献   

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