1,720,971 research outputs found
The Core Concepts, Competencies, and Grand Challenges of Comparative Vertebrate Anatomy and Morphology
No full textCore concepts offer coherence to the discourse of a scientific discipline and facilitate teaching by identifying large unifying themes that can be tailored to the level of the class and expertise of the instructor. This approach to teaching has been shown to encourage deeper learning that can be integrated across subdisciplines of biology and has been adopted by several other biology subdisciplines. However, Comparative Vertebrate Anatomy, although one of the oldest biological areas of study, has not had its core concepts identified. Here, we present five core concepts and seven competencies (skills) for Comparative Vertebrate Anatomy that came out of an iterative process of engagement with the broader community of vertebrate morphologists over a 3-year period. The core concepts are (A) evolution, (B) structure and function, (C) morphological development, (D) integration, and (E) human anatomy is the result of vertebrate evolution. The core competencies students should gain from the study of comparative vertebrate anatomy are (F) tree thinking, (G) observation, (H) dissection of specimens, (I) depiction of anatomy, (J) appreciation of the importance of natural history collections, (K) science communication, and (L) data integration. We offer a succinct description of each core concept and competency, examples of learning outcomes that could be used to assess teaching effectiveness, and examples of relevant resources for both instructors and students. Additionally, we pose a grand challenge to the community, arguing that the field of Comparative Vertebrate Anatomy needs to acknowledge racism, androcentrism, homophobia, genocide, slavery, and other influences in its history and address their lingering effects in order to move forward as a thriving discipline that is inclusive of all students and scientists and continues to generate unbiased knowledge for the betterment of humanity. Despite the rigorous process used to compile these core concepts and competencies, we anticipate that they will serve as a framework for an ongoing conversation that ensures Comparative Vertebrate Anatomy remains a relevant field in discovery, innovation, and training of future generations of scientists
Did shell-crushing crabs trigger an escalatory arms race in the aftermath of a Late Neogene regional mass extinction event? An experimental test
Full text linkAbstractA regional mass extinction event in the late Neogene western Atlantic is widely thought to have generated evolutionary opportunities for survivors, including enemy-related adaptation (escalation). The Strombus alatus species complex is one potential example of this phenomenon. Strombid gastropods are abundant in the Plio-Pleistocene fossil record and Recent in subtropical Florida, and the percentage of these shells bearing a row of short spines on the last whorl increased from nearly zero to almost 100% over this time. As shell ornamentation is one of the most frequently cited defenses against both peeling and crushing predators, we exposed live spined and spineless S. alatus to the stone crab Menippe, one of its natural enemies and the predator responsible for shells scars commonly found on modern and fossil S. alatus shells, to test whether the increase in expression of shell spines in this species complex is consistent with an adaptive or induced response to intensifying predation pressure from durophagous crabs. We also utilize random variation in prey shell length, diameter, and lip thickness to quantify the relative importance of additional shell parameters thought to deter attacks from durophagous crabs. The central finding of this study is that neither thicker shell lips nor the modern configuration of spines determine whether S. alatus will be more likely to survive Menippe attacks or have less severe shell damage. In our experiments, the only shell trait associated with reduced damage and increased probability of survival was whorl diameter. We conclude that menippid crabs, at least those crabs within the range of large, adult sizes used in this experiment, probably did not play a primary role in the changing expression of Strombus spines on the last whorl in the post-Pliocene of Florida or elsewhere in tropical America. This conclusion is consistent with the position that faunal-scale increases in expression of defensive shell traits in the post-Pliocene of Florida were driven more by differential extinction of lightly armored species than escalatory responses to increasing crab predation pressure. However this conclusion is tentative and additional data are needed to explore this hypothesis fully
Comparative Vertebrate and Human Anatomy: Ecology, Evolution, and Function
No full textThis book provides an ecology- and function-oriented approach to understanding the evolution of vertebrate structure. The text has a modular format, such that each module can be used as a stand-alone instructional tool, or grouped together as a comprehensive textbook, making the text versatile for use in courses with diverse structures. The text also includes human-specific modules for each anatomical system, as many small, liberal arts colleges teach comparative and human anatomy in a single course. Detailed, human-specific modules may be added or removed, as needed for individual courses, depending on the scope and learning objectives of the class.Published versio
Comparative jumping mechanics in plethodontid salamanders
No full textPlethodontid salamanders have a myriad of defense mechanisms with which to escape predation. One of the most poorly understood mechanisms is jumping, which is driven by lateral body bending; rapid straightening of the body propels the salamander into the air. One previous examination of jumping in one plethodontid salamander found little evidence of ontogenetic changes in the mechanics of jumping. Here, we investigate jumping in six species of plethodontid salamanders, across a wide array of body sizes. Comparing morphological and kinematic variables, jump height scaled with body size and forelimb length. Species differed in morphology, and when comparing kinematic variables across species, only bending duration differed. The lack of scaling patterns leads to several hypotheses, and further investigation of the morphology of the axial musculature is required.Published articl
Doing without: Jump performance after tail autotomy in three species of plethodontid salamanders
No full textThe ability of plethodontid salamanders to jump has been recognized for over 100 yr, but the mechanics of the jump are only now being elucidated. These salamanders often autotomize tails that can be as much as a third of the body mass. Tail loss alters jump performance in some lizards and therefore may also alter jump performance in the plethodontid salamanders. In this study, we used a high-speed camera to record subjects representing three species of plethodontid salamanders jumping with and without tails. The kinematic analyses indicate that take-off velocity, take-off angle, and maximum height are similar between salamanders with and without tails. Jump characteristics are highly variable within the individual for all salamanders (with or without tails) and this indicates that salamanders do not need to produce the same jump consistently to succeed in their primary task of escape. Better coordination might exist for arboreal plethodontid salamanders that use jumping for purposes other than escape. Future studies should focus on the in-air dynamics and landing kinematics of the salamander, as the tail plays a large role during in-air balance and landing control in other tetrapod species that jump.Allegheny College / Christine Scott Nelson FundPublished articl
Behavioural Versatility of the Giant Murex \u3cem\u3eMuricanthus fulvescens\u3c/em\u3e (Sowerby, 1834) (Gastropoda: Muricidae) in Interactions with Difficult Prey
No full textMuricanthus fulvescens, one of the largest muricid gastropods in the world, was once thought to be a behavioural specialist, using its shell to grind feeding holes in bivalve prey. New experimental observations, however, reveal that this predator employs up to four modes of predation, including selective use of shell grinding and edge drilling in interactions with the large, thick-shelled venerid clam Mercenaria campechiensis. Shell-grinding attacks were found to be slightly faster than edge-drilling attacks, but had a lower success rate. Choice of predatory mode was more strongly correlated with the prey\u27s anterior–posterior shell length than predator size. Smaller clams were attacked more frequently by shell grinding, while larger, thicker prey tended to be attacked by edge drilling. Several larger predators edge-drilled their prey successfully after first failing with the faster grinding behaviour; trial-and-error initiation of attacks with the more rapid grinding behaviour, however, was rare and expressed only by the largest predators. We also report an anecdotal observation of wall drilling and morphological evidence consistent with two modes of edge-drilling attacks, including drilling of larger holes for proboscis insertion and feeding and smaller, barely detectable (\u3c1 mm) holes for toxin injection. Toxin use is further supported by a lack of correlation between predator size and inner drill-hole dimensions. The occurrence of previously undetected diversity in predatory modes of M. fulvescens, a common, easily accessible species, demonstrates how much we have to learn about ecological versatility in muricids and its role in muricid evolution
A content analysis of 32 years of Shark Week documentaries
No full textDespite evidence of their importance to marine ecosystems, at least 32% of all chondrichthyan species are estimated or assessed as threatened with extinction. In addition to the logistical difficulties of effectively conserving wide-ranging marine species, shark conservation is believed to have been hindered in the past by public perceptions of sharks as dangerous to humans. Shark Week is a high-profile, international programming event that has potentially enormous influence on public perceptions of sharks, shark research, shark researchers, and shark conservation. However, Shark Week has received regular criticism for poor factual accuracy, fearmongering, bias, and inaccurate representations of science and scientists. This research analyzes the content and titles of Shark Week episodes across its entire 32 years of programming to determine if there are trends in species covered, research techniques featured, expert identity, conservation messaging, type of programming, and portrayal of sharks. We analyzed titles from 272 episodes (100%) of Shark Week programming and the content of all available (201; 73.9%) episodes. Our data demonstrate that the majority of episodes are not focused on shark bites, although such shows are common and many Shark Week programs frame sharks around fear, risk, and adrenaline. While criticisms of disproportionate attention to particular charismatic species (e.g. great whites, bull sharks, and tiger sharks) are accurate and supported by data, 79 shark species have been featured briefly at least once. Shark Week’s depictions of research and of experts are biased towards a small set of (typically visual and expensive) research methodologies and (mostly white, mostly male) experts, including presentation of many white male non-scientists as scientific experts. While sharks are more often portrayed negatively than positively, limited conservation messaging does appear in 53% of episodes analyzed. Results suggest that as a whole, while Shark Week is likely contributing to the collective public perception of sharks as bad, even relatively small alterations to programming decisions could substantially improve the presentation of sharks and shark science and conservation issues
Connecting Scientists With Students Using Social Media in an Undergraduate Science Course
No full textSocial media tools like Twitter allow scientists and other technical subject area experts to interact with the public in previously-unimaginable ways. Here we present a lesson plan in which undergraduates in a non-majors science course (introduction to marine biology) are asked to follow experts on Twitter from a carefully curated list and then complete a series of follow-up activities and reflections. This assignment is not only popular with students, but also supplemented their formal learning, allowed students to engage more deeply with subjects of personal interest, and has created life-long learning opportunities while improving science literacy. The lesson plan guidelines shared here can be adapted to other branches of science.Published articl
Trends in Chondrichthyan Research: An Analysis of Three Decades of Conference Abstracts
No full textGiven the conservation status and ecological, cultural, and commercial importance of chondrichthyan fishes, it is valuable to evaluate the extent to which research attention is spread across taxa and geographic locations and to assess the degree to which scientific research is appropriately addressing the challenges they face. Here we review trends in research effort over three decades (1985-2016) through content analysis of every abstract (n = 2,701) presented at the annual conference of the American Elasmobranch Society (AES), the oldest and largest professional society focused on the scientific study and management of these fishes. The most common research areas of AES abstracts were reproductive biology, movement/telemetry, age and growth, population genetics, and diet/feeding ecology, with different areas of focus for different study species or families. The most commonly studied species were large and charismatic (e.g., White Shark, Carcharodon carcharias), easily accessible to long-term established field research programs (e.g., Lemon Shark, Negaprion brevirostris, and Sandbar Shark, Carcharhinus plumbeus), or easily kept in aquaria for lab-based research (e.g., Bonnethead Shark, Sphyrna tiburo). Nearly 90% of all described chondrichthyan species have never been mentioned in an AES abstract, including some of the most threatened species in the Americas. The proportion of female* first authors has increased over time, though many current female* Society members are graduate students. Nearly half of all research presented at AES occurred in the waters of the United States rather than in the waters of developing nations where there are more threatened species and few resources for research or management. Presentations based on research areas such as paleontology and aquarium-based research have declined in frequency over time, and identified research priorities such as social science and interdisciplinary research are poorly represented. Possible research gaps and future research priorities for the study of chondrichthyan fishes are also discussed.Published articl
Students' Perceptions of FSBio 201, A CURE-Based Course that Scaffolds Research and Scientific Communication, Align with Learning Outcomes
No full textIncorporating active research opportunities into undergraduate curricula is one of the most cited elements demonstrated to improve inclusive excellence and retention in all STEM fields. Allegheny College has a long and nationally-recognized tradition of collaborative student-faculty research within the academic curriculum and as co-curricular opportunities. We present an example of the former, a Course-based Undergraduate Research Experience (CURE), FSBio 201, that has been central to Allegheny’s biology curriculum for over two decades. The course emphasizes biological research design, execution, and communication. We have coded and analyzed feedback from student evaluations and from the national CURE project database, both of which measure students’ perceptions and attitudes toward the course. The majority of the student feedback related to the course learning outcomes of fostering independent research and communication skills was positive. However, we also see areas for improvement, such as how we employ peer-to-peer mentoring and how we teach quantitative and computer-based skills. We conclude that students’ self-reported data are in line with our learning outcomes and provide FSBio 201 as a model for introducing college undergraduates to biological research.Allegheny College Biology Department and Biochemistry Programs and the National Science Foundation [IBN-9985265 to M.K.N.].Published articl
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