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Developing students’ ability to think about systems, as opposed to isolated facts, is of central importance in much of science teaching. Prior work in this area has focused on students’ recognition...

Background Many students solving quantitative problems in science struggle to apply mathematical instruction they have received to novel problems. The few students who succeed often draw on both their mathematical understanding of the equation and their scientific understanding of the phenomenon. Understanding the sensemaking opportunities provided during instruction is necessary to develop strategies for improving student outcomes. However, few studies have examined the types of sensemaking opportunities provided during instruction of mathematical equations in science classrooms and whether they are organized in ways that facilitate integration of mathematical and scientific understanding. This study uses a multiple case study approach to examine the sensemaking opportunities provided by four different instructors when teaching the same biological phenomenon, population growth. Two questions are addressed: (1) What types of sensemaking opportunities are provided by instructors, and (2) How are those sensemaking opportunities organized? The Sci-Math Sensemaking Framework, previously developed by the authors, was used to identify the types of sensemaking. Types and organization of sensemaking opportunities were compared across the four instructors. Results The instructors provided different opportunities for sensemaking of equations, even though they were covering the same scientific phenomenon. Sensemaking opportunities were organized in three ways, blended (previously described in studies of student problem solving as integration of mathematics and science resources), and two novel patterns, coordinated and adjacent. In coordinated sensemaking, two types of sensemaking in the same dimension (either mathematics or science) are explicitly connected. In adjacent sensemaking, two different sensemaking opportunities are provided within the same activity but not explicitly connected. Adjacent sensemaking was observed in three instructors’ lessons, but only two instructors provided opportunities for students to engage in blended sensemaking. Conclusions Instructors provide different types of sensemaking opportunities when teaching the same biological phenomenon, making different resources available to students. The organization of sensemaking also differed with only two instructors providing blended sensemaking opportunities. This result may explain why few students engage in the successful strategy of integrating mathematics and science resources when solving quantitative problems. Documentation of these instructional differences in types and organization of sensemaking provides guidance for future studies investigating the effect of instruction on student sensemaking.

Undergraduate students interact with the culture of scientific research when they participate in direct mentorship experiences and laboratory courses such as course-based undergraduate research experiences (CUREs). Much work has been done to explore how CUREs impact the interest, motivation, and retention of undergraduate students in science. However, little work has been done exploring students' experiences and perceptions of the culture of scientific research in the CURE context, and how different CURE models representing different subfields of science impact these experiences and perceptions. This study explored which cultural aspects of scientific research students experienced after participating in a CURE and whether their perceptions of those cultural aspects differed based on students' participation in a bench-based or computer-based research project. Students discussed the Practices and Norms/Expectations of scientific research most frequently. Students in the bench-based and computer-based project areas mentioned different cultural aspects as important to their experiences. Bench-based and computational students also had different perceptions of some of the same cultural aspects, including Teamwork, FreedomIndependence, and PersistenceResilience. These results suggest that different CURE models differentially impact students' experiences and perceptions of the culture of scientific research, which has implications for examining how students move into scientific research.

When conducting biological investigations, experts constantly integrate their conceptual and quantitative understanding of variation with the design and analysis of the investigation. This process is difficult for students, because curricula often treat these concepts as separate components. This study describes the effect of a curricular intervention aimed at improving students' conceptual and quantitative understanding of variation in the context of experimental design and analysis. A model-based intervention curriculum consisting of five short modules was implemented in an introductory biology laboratory course. All students received the regular laboratory curriculum, and half of the students also received the Intervention curriculum. Students' understanding of variation was assessed using a published 16-question multiple-choice instrument designed and validated by the research team. Students were assessed before and after the intervention was implemented, and normalized gain scores were calculated. Students who received the intervention showed significantly higher normalized gains than students who did not receive the intervention. This effect was not influenced by students' gender or exposure to prior statistics courses and persisted into and through the following semester's laboratory course. These results provide support for the use of model-based approaches to improve students' understanding of biological variation in experimental design and analysis.

Interdisciplinary research is the synergistic combination of two or more disciplines to achieve one research objective. Current research highlights the importance of interdisciplinary research in science education, particularly between educational experts within a particular science discipline (discipline-based education researchers) and those who study human learning in a more general sense (learning scientists). However, this type of interdisciplinary research is not common and little empirical evidence exists that identifies barriers and possible solutions. We hosted a pre-conference workshop for Discipline-Based Educational Researchers and Learning Scientists designed to support interdisciplinary collaborations. We collected evidence during our workshop regarding barriers to interdisciplinary collaborations in science education, perceptions of perceived cohesion in participants’ home university departments and professional communities, and the impact of our workshop on fostering new connections. Based on participants’ responses, we identified three categories of barriers, Disciplinary Differences, Professional Integration, and Collaborative Practice. Using a post-conference survey, we found an inverse pattern in perceived cohesion to home departments compared to self-identified professional communities. Additionally, we found that after the workshop participants reported increased connections across disciplines. Our results provide empirical evidence regarding challenges to interdisciplinary research in science education and suggest that small professional development workshops have the potential for facilitating durable interdisciplinary networks where participants feel a sense of belonging not always available in their home departments.

Scientific research has a culture that can be challenging to enter. Different aspects of this culture may act as barriers or entry points for different people. Recognition of these barriers and entry points requires identifying aspects of the culture of scientific research and synthesizing them into a single, descriptive framework. A systematic literature review encompassing a two-pronged search strategy, descriptive mapping of ideas, and consensus building, was performed to identify aspects of scientific research culture. This resulted in the Culture of Scientific Research (CSR) Framework, composed of 31 cultural aspects categorized as either Practices, Norms/Expectations, or Values/Beliefs. Additional evidence of validity was collected through a survey that asked biological researchers to indicate which aspects in the framework were relevant to their experiences of research. The majority of survey respondents (n = 161) perceived the 31 aspects in the CSR Framework as relevant to biological research. This framework provides a consistent structure for describing the experiences of people engaging with the culture of scientific research. The literature review included literature from multiple disciplines, so the CSR Framework should be broadly applicable. Future applications of the CSR Framework include identifying possible barriers and entry points experienced by groups currently underrepresented in scientific research.

Biologists consider variability during biological investigations. A robust quantitative understanding of variability is particularly important during data analysis, where statistics are used to quantify variation and draw conclusions about phenomena while accounting for variation. Many students struggle to correctly apply a quantitative understanding of variation to statistically analyze data. We present quantitative and qualitative analyses of introductory biology students’ responses on two pairs of multiple-choice questions querying two concepts related to the quantitative analysis of variation. More students correctly identify a mathematical expression of variation than correctly interpret it. Many students correctly interpret a nonsignificant p-value in the context of a very small sample size, but fewer students do so in the context of a large sample size. These results imply that many students have an incomplete quantitative understanding of variation. These findings suggest that instruction focusing on conceptual understanding, not procedural problem solving, may elevate students’ quantitative understanding of variation.

Scientific ideas are often expressed as mathematical equations. Understanding the ideas contained within these equations requires making sense of both the embedded mathematics knowledge and scientific knowledge. Students who can engage in this type of blended sensemaking are more successful at solving novel or more complex problems with these equations. However, students often tend to rely on algorithmic/procedural approaches and struggle to make sense of the underlying science. This deficit may partly be the fault of instruction that focuses on superficial connections with the science and mathematics knowledge such as defining variables in the equation and demonstrating step-by-step procedures for solving problems. Research into the types of sensemaking of mathematical equations in science contexts is hindered by the absence of a shared framework. Therefore, a review of the literature was completed to identify themes addressing sensemaking of mathematical equations in science. These themes were compiled into nine categories, four in the science sensemaking dimension and five in the mathematics sensemaking dimension. This framework will allow for comparison across studies on the teaching and learning of mathematical equations in science and thus help to advance our understanding of how students engage in sensemaking when solving quantitative problems as well as how instruction influences this sensemaking.

Instruments for assessing secondary students’ conceptual understanding of core concepts in biology are needed by educational practitioners and researchers alike. Most instruments available for secondary biology (years 9 to 12) focus only on highly specific biological concepts instead of multiple core concepts. This study describes the development of a 25-item instrument designed to fill this gap, the High School Biology Concept Inventory (HS-BCI). The HS-BCI not only assesses student knowledge of key biological concepts but also alternative conceptions. Using Rasch theory, the initial instrument was constructed from a pool of 61 instrument items using test results from 1015 students. The final 25-item instrument was validated with 1955 students. The results provide reliability and validity evidence for the HS-BCI. The findings suggest that it can be utilized to assess both conceptual knowledge and alternative conceptions.

The National Research Council framework for science education and the Next Generation Science Standards have developed a need for additional research and development of curricula that is both technologically model-based and includes engineering practices. This is especially the case for biology education. This paper describes a quasi-experimental design study to test the effectiveness of a model-based curriculum focused on the concepts of natural selection and population ecology that makes use of Excel modeling tools (Modeling Instruction in Biology with Excel, MBI-E). The curriculum revolves around the bio-engineering practice of controlling an invasive species. The study takes place in the Midwest within ten high schools teaching a regular-level introductory biology class. A post-test was designed that targeted a number of common misconceptions in both concept areas as well as representational usage. The results of a post-test demonstrate that the MBI-E students significantly outperformed the traditional classes in both natural selection and population ecology concepts, thus overcoming a number of misconceptions. In addition, implementing students made use of more multiple representations as well as demonstrating greater fascination for science.

Variation is an important concept that underlies experimental design and data analysis. Incomplete understanding of variation can preclude students from designing experiments that adequately manage organismal and experimental variation, and from accurately conducting and interpreting statistical analyses of data. Because of the lack of assessment instruments that measure students' ideas about variation in the context of biological investigations, we developed the Biological Variation in Experimental Design and Analysis (BioVEDA) assessment. Psychometric analyses indicate that BioVEDA assessment scores are reliable/precise. We provide evidence that the BioVEDA instrument can be used to evaluate students' understanding of biological variation in the context of experimental design and analysis relative to other students and to their prior scores.

Course-based undergraduate research experiences (CUREs) have the potential to improve undergraduate biology education by involving large numbers of students in research. CUREs can take a variety of forms with different affordances and constraints, complicating the evaluation of design features that might contribute to successful outcomes. In this study, we compared students’ responses to three different research experiences offered within the same course. One of the research experiences involved purely computational work, whereas the other two offerings were bench-based research experiences. We found that students who participated in computer-based research reported at least as much interest in their research projects, a higher sense of achievement, and a higher level of satisfaction with the course compared with students who did bench-based research projects. In open-ended comments, similar proportions of students in each research area expressed some sense of project ownership as contributing positively to their course experiences. Their comments also supported the finding that experiencing a sense of achievement was a predictor of course satisfaction. We conclude that both computer-based and bench-based CUREs can have positive impacts on students’ attitudes. Development of more computer-based CUREs might allow larger numbers of students to benefit from participating in a research experience.

The use of scientific models and modeling in science education has been demonstrated to achieve cognitive gains in several science disciplines (Jackson et al. in Sci Educ 17:10–17, 2008; Malone et al. in Paper presentation at NARST 2017: the 2017 international conference of the national association for research in science teaching, San Antonio, TX, 2017; Schuchardt and Schunn in Sci Educ 100:290–320, 2016). In the area of evolution, prior researchers have studied how students view models and how to support student learning through the use of computer-based modeling. Frequently, researchers used case studies with small samples of students describing the impact of modeling on conceptual change (Passmore and Stewart in J Res Sci Teach 39:185–204, 2002; Wagh and Wilensky in Proceedings of constructionism 2014, 2014). There is a dearth of quasi-experimental studies in secondary classrooms that examine how the use of models and modeling can affect the cognitive gains of learners in biology and evolution in particularly. This chapter will discuss an evolution unit grounded in the use of modeling and its effects on learning in evolution and attitudes toward science in general. The first section will include a discussion of the modeling activities used in the unit, such as hands-on inquiry activities to develop the model as well as deployments of the model in numerous biology contexts. The second section will include details of the mixed methods analysis of the effects of this curriculum on student learning in evolution.

Amid calls for integrating science, technology, engineering, and mathematics (iSTEM) in K–12 education, there is a pressing need to uncover productive methods of integration. Prior research has shown that increasing contextual linkages between science and mathematics is associated with student problem solving and conceptual understanding. However, few studies explicitly test the benefits of specific instructional mechanisms for fostering such linkages. We test the effect of students developing a modeled process mathematical equation of a scientific phenomenon. Links between mathematical variables and processes within the equation and fundamental entities and processes of the scientific phenomenon are embedded within the equation. These connections are made explicit as students participate in model development. Pre–post gains are tested in students from diverse high school classrooms studying inheritance. Students taught using this instructional approach are contrasted against students in matched classrooms implementing more traditional instruction (Study 1) or prior traditional instruction from the same teachers (Study 2). Students given modeled process instruction improved more in their ability to solve complex mathematical problems compared to traditionally instructed students. These modeled process students also show increased conceptual understanding of mathematically modeled processes. The observed effects are not due to differences in instructional time or teacher effects.

Prior studies have shown that students have difficulty understanding the role of mutation in evolution and genetics. However, little is known about unifying themes underlying students’ difficulty with mutation. In this study, we examined students’ written explanations about mutation from a cognitive science perspective. According to one cognitive perspective, scientific phenomena can be perceived as entities or processes, and the miscategorization of processes as entities can lead to noncanonical ideas about scientific phenomena that are difficult to change. Students’ incorrect categorization of processes as entities is well documented in physics but has not been studied in biology. Unlike other scientific phenomena that have been studied, the word “mutation” refers to both the process causing a change in the DNA and the entity, the altered DNA, making mutation a relevant concept for exploration and extension of this theory. In this study, we show that, even after instruction on mutation, the majority of students provided entity-focused descriptions of mutation in response to a question that prompted for a process-focused description in a lizard or a bacterial population. Students’ noncanonical ideas about mutation occurred in both entity- and process-focused descriptions. Implications for conceptual understanding and instruction are discussed.

In the fall of 2011 five secondary level biology teachers in the northeast United States implemented an experimental instructional module that challenged their students with a design problem. This challenge required students to perform both mathematical analysis and the engineering application of biological concepts in order to reach a resolution. Specifically, given the parental genotypes of two gecko parents, students were tasked to: (a) mathematically represent the relative frequency of all possible offspring genotypes; and (b) design a systematic breeding program for the geckos that would consistently produce a rare and highly desired genotype as a result. Presented here is a study of how the participating teachers made sense of the mathematics and engineering design applied to the biological process of inheritance, and their reflections on their own implementations of the instructional module. Emergent themes dealt with the limitations of mathematics in teachers’ own biology education, their lack of experience with either engineering or design, and their efforts to help students address similar circumstances.

Almost 1% of human infants are born with urogenital abnormalities, many of which are linked to irregular connections between the distal ureters and the bladder. During development, ureters migrate by an unknown mechanism from their initial integration site in the Wolffian ducts up to the base of the bladder in a process that we call ureter maturation. Rara(-/-) Rarb2(-/-) mice display impaired vitamin A signaling and develop syndromic urogenital malformations similar to those that occur in humans, including renal hypoplasia, hydronephrosis and mega-ureter, abnormalities also seen in mice with mutations in the proto-oncogene Ret. Here we show that ureter maturation depends on formation of the 'trigonal wedge', a newly identified epithelial outgrowth from the base of the Wolffian ducts, and that the distal ureter abnormalities seen in Rara(-/-) Rarb2(-/-) and Ret(-/-) mutant mice are probably caused by a failure of this process. Our studies indicate that formation of the trigonal wedge may be essential for correct insertion of the distal ureters into the bladder, and that these events are mediated by the vitamin A and Ret signaling pathways.

During spinal cord development, commissural (C) neurons, located near the dorsal midline, send axons ventrally and across the floor plate (FP). The trajectory of these axons toward the FP is guided in part by netrins. The mechanisms that guide the early phase of C axon extension, however, have not been resolved. We show that the roof plate (RP) expresses a diffusible activity that repels C axons and orients their growth within the dorsal spinal cord. Bone morphogenetic proteins (BMPs) appear to act as RP-derived chemorepellents that guide the early trajectory of the axons of C neurons in the developing spinal cord: BMP7 mimics the RP repellent activity for C axons in vitro, can act directly to collapse C growth cones, and appears to serve an essential function in RP repulsion of C axons.

Extracellular matrix molecules, including laminin, affect the development of enteric neurons and accumulate in the aganglionic colon of ls/ls mice. Quantitative Northern analysis revealed that mRNAs encoding the beta 1 and gamma 1 subunits of laminin and collagens alpha 1(IV) and alpha 2(IV) are increased in the colons of ls/ls mice. Transcripts of laminin alpha 1 were evaluated quantitatively with reverse transcription and the competitive polymerase chain reaction (RT-cPCR). The abundance of laminin alpha 1 transcripts was developmentally regulated, but greater in the ls/ls than the wild-type colon at each age examined. In situ hybridization revealed that transcripts in the colon encoding laminin alpha 1 and beta 1 and collagen alpha 2(IV) were initially expressed in the endoderm, but by E15, expression shifted to cells of the colonic mesenchyme (ls/ls > wild type) where crest-derived cells migrate. The expression of laminin alpha 1 was examined in the totally aganglionic intestine of E15 and newborn c-ret -/- mice, to determine whether an increase occurs when neurogenesis fails independently of the ls/ls defect. RT-cPCR revealed no difference from control in mRNA encoding laminin alpha 1 in the c-ret -/- colon in either E15 or newborn animals. The accumulation of immunohistochemically demonstrable laminin that is prominent in the newborn ls/ls colon could not be detected in that of c-ret -/- animals. These observations suggest that transcripts encoding laminin-1 and collagen (IV) are increased in the colon and surrounding pelvic mesenchyme of ls/ls mice because of an intrinsic lesion, rather than a secondary consequence of aganglionosis. The data are compatible with the hypothesis that the increased expression of laminin-1 contributes to the failure of crest-derived cells to complete their colonization of the ls/ls colon.

The c-ret gene encodes a receptor tyrosine kinase that is expressed in the Wolffian duct and ureteric bud of the developing excretory system. Newborn mice homozygous for a mutation in c-ret displayed renal agenesis or severe hypodysplasia, suggesting a critical role for this gene in metanephric kidney development. To investigate the embryological basis of these defects, we characterized the early development of the excretory system in mutant homozygotes, and observed a range of defects in the formation, growth and branching of the ureteric bud, which account for the spectrum of renal defects seen at birth. Co-culture of isolated ureteric buds and metanephric mesenchyme show that the primary defect is intrinsic to the ureteric bud. While the mutant bud failed to respond to induction by wild-type mesenchyme, mutant mesenchyme was competent to induce the growth and branching of the wild-type bud. Furthermore, the mutant metanephric mesenchyme displayed a normal capacity to differentiate into nephric tubules when co-cultured with embryonic spinal cord. These findings suggest a model in which c-ret encodes the receptor for a (yet to be identified) factor produced by the metanephric mesenchyme, which mediates the inductive effects of this tissue upon the ureteric bud. This factor appears to stimulate the initial evagination of the ureteric bud from the Wolffian duct, as well as its subsequent growth and branching.

c-ret encodes a tyrosine kinase receptor that is necessary for normal development of the mammalian enteric nervous system. Germline mutations in c-ret lead to congenital megacolon in humans, while a loss-of-function allele (ret.k −) causes intestinal aganglionosis in mice. Here we examine in detail the function of c-ret during neurogenesis, as well as the lineage relationships among cell populations in the enteric nervous system and the sympathetic nervous system that are dependent on c-ret function. We report that, while the intestine of newborn ret.k − mice is devoid of enteric ganglia, the esophagus and stomach are only partially affected; furthermore, the superior cervical ganglion is absent, while more posterior sympathetic ganglia and the adrenal medulla are unaffected. Analysis of mutant embryos shows that the superior cervical ganglion anlage is present at E10.5, but absent by E12.5, suggesting that c-ret is required for the survival or prolif-eration of sympathetic neuroblasts. In situ hybridization studies, as well as direct labelling of cells with DiI, indicate that a common pool of neural crest cells derived from the postotic hindbrain normally gives rise to most of the enteric nervous system and the superior cervical ganglion, and is uniquely dependent on c-ret function for normal develop-ment. We term this the sympathoenteric lineage. In contrast, a distinct sympathoadrenal lineage derived from trunk neural crest forms the more posterior sympathetic ganglia, and also contributes to the foregut enteric nervous system. Overall, our studies reveal previously unknown complexities of cell lineage and genetic control mechanisms in the developing mammalian peripheral nervous system.

Receptor tyrosine kinases (RTKs) are cell-surface molecules that transduce signals for cell growth and differentiation. The RTK encoded by the c-ret proto-oncogene is rearranged and constitutively activated in a large proportion of thyroid papillary carcinomas, and germ-line point mutations in c-ret seem to be responsible for the dominantly inherited cancer syndromes multiple endocrine neoplasia (MEN) types 2A and B. The gene is expressed in the developing central and peripheral nervous systems (sensory, autonomic and enteric ganglia) and the excretory system (Wolffian duct and ureteric bud epithelium) of mice, indicating that it may play a role in normal development. Here we show that mice homozygous for a targeted mutation in c-ret develop to term, but die soon after birth, showing renal agenesis or severe dysgenesis, and lacking enteric neurons throughout the digestive tract. Ret is thus an essential component of a signalling pathway required for renal organogenesis and enteric neurogenesis.

Brain stem muscarinic cholinergic pathways are important in respiratory carbon dioxide (CO2) chemosensitivity. Defects in the muscarinic system have been reported in children with congenital/developmental disorders of respiratory control such as sudden infant death syndrome (SIDS) and congenital central hypoventilation syndrome (CCHS). This early onset of disease suggests a possible genetic basis. The muscarinic system is part of the autonomic nervous system which develops from the neural crest. Ret proto-oncogene is important for this development. Thus, a potential role for ret in the development of respiratory CO2 chemosensitivity was considered. Using plethysmography, we assessed the ventilatory response to inhaled CO2 in the unanesthetized offsprings of ret +/- mice. Fractional increases in minute ventilation during hypercapnia relative to isocapnia were 5.1 +/- 3.2, 3.0 +/- 1.6 and 1.4 +/- 0.8 for the ret +/+, ret +/- and ret +/- mice, respectively. The ret knockout mice have a depressed ventilatory response to inhaled CO2. Therefore, the ret gene is an important factor in the pathway of neuronal development which allow respiratory CO2 chemosensitivity.

Receptor tyrosine kinases play a critical role in transducing signals involved in cell growth and differentiation. The c-ret proto-oncogene is a member of the receptor tyrosine kinase gene superfamily originally identified by its transforming ability. Somatic mutations of c-ret are responsible for a large proportion of thyroid papillary carcinomas, while germ-line mutations are responsible for multiple endocrine neoplasia types 2A and 2B, dominantly inherited cancer syndromes characterized by multiple tumours of neuroectodermal origin. In addition to its role in tumour formation. c-ret is thought to have a developmental role since mutations of the gene have been implicated in the aetiology of Hirschsprung's syndrome (congenital megacolon). A targeted mutation in the murine c-ret locus shows that the ret receptor is required for normal development of two lineally unrelated systems, the excretory system and the enteric nervous system.