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Reed JM, Wolfe BE, Romero LM. Is resilience a unifying concept for the biological sciences? iScience 2024; 27:109478. [PMID: 38660410 PMCID: PMC11039332 DOI: 10.1016/j.isci.2024.109478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/26/2024] Open
Abstract
There is increasing interest in applying resilience concepts at different scales of biological organization to address major interdisciplinary challenges from cancer to climate change. It is unclear, however, whether resilience can be a unifying concept consistently applied across the breadth of the biological sciences, or whether there is limited capacity for integration. In this review, we draw on literature from molecular biology to community ecology to ascertain commonalities and shortcomings in how resilience is measured and interpreted. Resilience is studied at all levels of biological organization, although the term is often not used. There is a suite of resilience mechanisms conserved across biological scales, and there are tradeoffs that affect resilience. Resilience is conceptually useful to help diverse researchers think about how biological systems respond to perturbations, but we need a richer lexicon to describe the diversity of perturbations, and we lack widely applicable metrics of resilience.
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Affiliation(s)
- J. Michael Reed
- Department of Biology, Tufts University, Medford 02155, MA, USA
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2
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Van Gorp MJW, Goyens J, Alfaro ME, Van Wassenbergh S. Keels of boxfish carapaces strongly improve stabilization against roll. J R Soc Interface 2022; 19:20210942. [PMID: 35472270 PMCID: PMC9042571 DOI: 10.1098/rsif.2021.0942] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Boxfish (Ostraciidae) have peculiar body shapes, with conspicuous keels formed by their bony carapaces. Previous studies have proposed various hydrodynamic roles for these keels, including reducing drag during swimming, contributing to passive stabilization of the swimming course, or providing resistance against roll rotations. Here, we tested these hypotheses using computational fluid dynamics simulations of five species of Ostraciidae with a range of carapace shapes. The hydrodynamic performance of the original carapace surface models, obtained from laser scanning of museum specimens, was compared with models where the keels had been digitally reduced. The original carapaces showed no reduced drag or increased passive stability against pitch and yaw compared to the reduced-keel carapaces. However, consistently for all studied species, a strong increase in roll drag and roll-added mass was observed for the original carapaces compared to the reduced-keel carapaces, despite the relatively small differences in keel height. In particular, the damping of roll movement by resistive drag torques increased considerably by the presence of keels. Our results suggest that the shape of the boxfish carapace is important in enabling the observed roll-free forward swimming of boxfish and may facilitate the control of manoeuvres.
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Affiliation(s)
- Merel J W Van Gorp
- Department of Biology, Universiteit Antwerpen, Universiteitsplein 1, 2610 Antwerpen, Belgium
| | - Jana Goyens
- Department of Biology, Universiteit Antwerpen, Universiteitsplein 1, 2610 Antwerpen, Belgium
| | - Michael E Alfaro
- Department of Ecology and Evolutionary Biology, University of California, 2154 Terasaki Life Sciences Building, Los Angeles, CA 90095, USA
| | - Sam Van Wassenbergh
- Department of Biology, Universiteit Antwerpen, Universiteitsplein 1, 2610 Antwerpen, Belgium
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Decoding the Relationships between Body Shape, Tail Beat Frequency, and Stability for Swimming Fish. FLUIDS 2020. [DOI: 10.3390/fluids5040215] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
As fish swim through a fluid environment, they must actively use their fins in concert to stabilize their motion and have a robust form of locomotion. However, there is little knowledge of how these forces act on the fish body. In this study, we employ a 3D immersed boundary model to decode the relationship between roll, pitch, and yaw of the fish body and the driving forces acting on flexible fish bodies. Using bluegill sunfish as our representative geometry, we first examine the role of an actuating torque on the stability of the fish model, with a torque applied at the head of the unconstrained fish body. The resulting kinematics is a product of the passive elasticity, fluid forces, and driving torque. We then examine a constrained model to understand the role that fin geometry, body elasticity, and frequency play on the range of corrective forces acting on the fish. We find non-monotonic behavior with respect to frequency, suggesting that the effective flexibility of the fins play an important role in the swimming performance.
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Gordon MS, Lauritzen DV, Wiktorowicz-Conroy AM, Rutledge KM. Aracaniform Swimming: A Proposed New Category of Swimming Mode in Bony Fishes (Teleostei: Tetraodontiformes: Aracanidae). Physiol Biochem Zool 2020; 93:235-242. [PMID: 32255729 DOI: 10.1086/708163] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The deepwater boxfishes of the family Aracanidae are the phylogenetic sister group of the shallow-water, generally more tropical boxfishes of the family Ostraciidae. Both families are among the most derived groups of teleosts. All members of both families have armored bodies, the forward 70% of which are enclosed in rigid bony boxes (carapaces). There is substantial intragroup variation in both groups in body shapes, sizes, and ornamentation of the carapaces. Swimming-related morphology, swimming mode, biomechanics, kinematics, and hydrodynamics have been studied in detail in multiple species of the ostraciids. Ostraciids are all relatively high-performance median and paired fin swimmers. They are highly maneuverable. They swim rectilinearly with substantial dynamic stability and efficiency. Aracanids have not been previously studied in these respects. This article describes swimming-related aspects of morphology, swimming modes, biomechanics, and kinematics in two south Australian species (striped cowfish and ornate cowfish) that are possibly representative of the entire group. These species differ morphologically in many respects, both from each other and from ostraciids. There are differences in numbers, sizes, and placements of keels on carapaces. The most important differences from ostraciids are openings in the posterior edges of the carapaces behind the dorsal and anal fins. The bases of those fins in ostraciids are enclosed in bone. The openings in aracanids free the fins and tail to move. As a result, aracanids are body and caudal fin swimmers. Their overall swimming performances are less stable, efficient, and effective. We propose establishing a new category of swimming mode for bony fishes called "aracaniform swimming."
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Boute PG, Van Wassenbergh S, Stamhuis EJ. Modulating yaw with an unstable rigid body and a course-stabilizing or steering caudal fin in the yellow boxfish ( Ostracion cubicus). ROYAL SOCIETY OPEN SCIENCE 2020; 7:200129. [PMID: 32431903 PMCID: PMC7211845 DOI: 10.1098/rsos.200129] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Accepted: 03/16/2020] [Indexed: 06/11/2023]
Abstract
Despite that boxfishes have a rigid carapace that restricts body undulation, they are highly manoeuvrable and manage to swim with remarkably dynamic stability. Recent research has indicated that the rigid body shape of boxfishes shows an inherently unstable response in its rotations caused by course-disturbing flows. Hence, any net stabilizing effect should come from the fishes' fins. The aim of the current study was to determine the effect of the surface area and orientation of the caudal fin on the yaw torque exerted on the yellow boxfish, Ostracion cubicus, a square cross-sectional shaped species of boxfish. Yaw torques quantified in a flow tank using a physical model with an attachable closed or open caudal fin at different body and tail angles and at different water flow speeds showed that the caudal fin is crucial for controlling yaw. These flow tank results were confirmed by computational fluid dynamics simulations. The caudal fin acts as both a course-stabilizer and rudder for the naturally unstable rigid body with regard to yaw. Boxfishes seem to use the interaction of the unstable body and active changes in the shape and orientation of the caudal fin to modulate manoeuvrability and stability.
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Affiliation(s)
- Pim G. Boute
- Department of Ocean Ecosystems, Energy and Sustainability Research Institute Groningen, Faculty of Science and Engineering, University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands
- Experimental Zoology Group, Department of Animal Sciences, Wageningen University & Research, De Elst 1, 6708 WD Wageningen, The Netherlands
| | - Sam Van Wassenbergh
- Department of Biology, University of Antwerp, Universiteitsplein 1, 2610 Antwerpen, Belgium
| | - Eize J. Stamhuis
- Department of Ocean Ecosystems, Energy and Sustainability Research Institute Groningen, Faculty of Science and Engineering, University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands
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Mayerl CJ, Youngblood JP, Rivera G, Vance JT, Blob RW. Variation in Morphology and Kinematics Underlies Variation in Swimming Stability and Turning Performance in Freshwater Turtles. Integr Org Biol 2018. [DOI: 10.1093/iob/oby001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Abstract
Among swimming animals, stable body designs often sacrifice performance in turning, and high turning performance may entail costs in stability. However, some rigid-bodied animals appear capable of both high stability and turning performance during swimming by propelling themselves with independently controlled structures that generate mutually opposing forces. Because such species have traditionally been studied in isolation, little is known about how variation within rigid-bodied designs might influence swimming performance. Turtles are a lineage of rigid-bodied animals, in which most species use contralateral limbs and mutually opposing forces to swim. We tested the stability and turning performance of two species of turtles, the pleurodire Emydura subglobosa and the cryptodire Chrysemys picta. Emydura subglobosa exhibited both greater stability and turning performance than C. picta, potentially through the use of subequally-sized (and larger) propulsive structures, faster limb movements, and decreased limb excursions. These data show how, within a given body design, combinations of different traits can serve as mechanisms to improve aspects of performance with competing functional demands.
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Affiliation(s)
- C J Mayerl
- Department of Biological Sciences, Clemson University, Clemson, SC 29634, USA
| | - J P Youngblood
- School of Life Sciences, Arizona State University, Tempe, AZ 85287, USA
| | - G Rivera
- Department of Biology, Creighton University, Omaha, NE 68178, USA
| | - J T Vance
- Department of Biology, College of Charleston, Charleston, SC 29424, USA
| | - R W Blob
- Department of Biological Sciences, Clemson University, Clemson, SC 29634, USA
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Mayerl CJ, Sansone AM, Stevens LM, Hall GJ, Porter MM, Rivera G, Blob RW. The impact of keels and tails on turtle swimming performance and their potential as models for biomimetic design. BIOINSPIRATION & BIOMIMETICS 2018; 14:016002. [PMID: 30403189 DOI: 10.1088/1748-3190/aae906] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Stability and turning performance are two key metrics of locomotor performance in animals, and performance in both of these metrics can be improved through a variety of morphological structures. Aquatic vehicles are often designed with keels and rudders to improve their stability and turning performance, but how keels and rudders function in rigid-bodied animals is less understood. Aquatic turtles are a lineage of rigid-bodied animals that have the potential to function similarly to engineered vehicles, and also might make use of keels and rudders to improve their stability and turning performance. To test these possibilities, we trained turtles to follow a mechanically controlled prey stimulus under three sets of conditions: with no structural modifications, with different sized and shaped keels, and with restricted tail use. We predicted that keels in turtles would function similarly to those in aquatic vehicles to reduce oscillations, and that turtles would use the tail like a rudder to reduce oscillations and improve turning performance. We found that the keel designs we tested did not reduce oscillations in turtles, but that the tail was used similarly to a rudder, with benefits to both the magnitude of oscillations they experienced and turning performance. These data show how variation in the accessory structures of rigid-bodied animals can impact swimming performance, and suggest that such variation among turtles could serve as a biomimetic model in designing aquatic vehicles that are stable as well as maneuverable and agile.
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Affiliation(s)
- Christopher J Mayerl
- Department of Biological Sciences, Clemson University, Clemson, SC 29634, United States of America. Author to whom any correspondence should be addressed
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Fish FE, Lauder GV. Control surfaces of aquatic vertebrates: active and passive design and function. ACTA ACUST UNITED AC 2018; 220:4351-4363. [PMID: 29187618 DOI: 10.1242/jeb.149617] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Aquatic vertebrates display a variety of control surfaces that are used for propulsion, stabilization, trim and maneuvering. Control surfaces include paired and median fins in fishes, and flippers and flukes in secondarily aquatic tetrapods. These structures initially evolved from embryonic fin folds in fishes and have been modified into complex control surfaces in derived aquatic tetrapods. Control surfaces function both actively and passively to produce torque about the center of mass by the generation of either lift or drag, or both, and thus produce vector forces to effect rectilinear locomotion, trim control and maneuvers. In addition to fins and flippers, there are other structures that act as control surfaces and enhance functionality. The entire body can act as a control surface and generate lift for stability in destabilizing flow regimes. Furthermore, control surfaces can undergo active shape change to enhance their performance, and a number of features act as secondary control structures: leading edge tubercles, wing-like canards, multiple fins in series, finlets, keels and trailing edge structures. These modifications to control surface design can alter flow to increase lift, reduce drag and enhance thrust in the case of propulsive fin-based systems in fishes and marine mammals, and are particularly interesting subjects for future research and application to engineered systems. Here, we review how modifications to control surfaces can alter flow and increase hydrodynamic performance.
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Affiliation(s)
- Frank E Fish
- Department of Biology, West Chester University, West Chester, PA 19383, USA
| | - George V Lauder
- Museum of Comparative Zoology, Harvard University, Cambridge, MA 02138, USA
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Zheng X, Wang C, Fan R, Xie G. Artificial lateral line based local sensing between two adjacent robotic fish. BIOINSPIRATION & BIOMIMETICS 2017; 13:016002. [PMID: 28949301 DOI: 10.1088/1748-3190/aa8f2e] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The lateral line system (LLS) is a mechanoreceptive organ system with which fish and aquatic amphibians can effectively sense the surrounding flow field. The reverse Kármán vortex street (KVS), known to be a typical thrust-producing wake, is commonly observed in fish-like locomotion and is known to be generated by fish's tails. The vortex street generally reflects the motion information of the fish. A fish can use LLS to detect such vortex streets generated by its neighboring fish, thus sensing its own state and the states of its neighbors in a school of fish. Inspired by this typical biological phenomenon, we design a robotic fish with an onboard artificial lateral line system (ALLS) composed of pressure sensor arrays and use it to detect the reverse KVS-like vortex wake generated by its adjacent robotic fish. Specifically, the vortex wake results in hydrodynamic pressure variations (HPVs) in the flow field. By measuring the HPV using the ALLS and extracting meaningful information from the pressure sensor readings, the oscillating frequency/amplitude/offset of the adjacent robotic fish, the relative vertical distance and the relative yaw/pitch/roll angle between the robotic fish and its neighbor are sensed efficiently. This work investigates the hydrodynamic characteristics of the reverse KVS-like vortex wake using an ALLS. Furthermore, this work demonstrates the effectiveness and practicability of an artificial lateral line in local sensing for adjacent underwater robots, indicating the potential to improve close-range interaction and cooperation within a group of underwater vehicles through the application of ALLSs in the near future.
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Affiliation(s)
- Xingwen Zheng
- State Key Laboratory for Turbulence and Complex Systems, College of Engineering, Peking University, Beijing, 100871, People's Republic of China
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10
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Bang K, Kim J, Lee SI, Choi H. Hydrodynamic role of longitudinal dorsal ridges in a leatherback turtle swimming. Sci Rep 2016; 6:34283. [PMID: 27694826 PMCID: PMC5046118 DOI: 10.1038/srep34283] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Accepted: 09/09/2016] [Indexed: 11/15/2022] Open
Abstract
Leatherback sea turtles (Dermochelys coriacea) are known to have a superior diving ability and be highly adapted to pelagic swimming. They have five longitudinal ridges on their carapace. Although it was conjectured that these ridges might be an adaptation for flow control, no rigorous study has been performed to understand their hydrodynamic roles. Here we show that these ridges are slightly misaligned to the streamlines around the body to generate streamwise vortices, and suppress or delay flow separation on the carapace, resulting in enhanced hydrodynamic performances during different modes of swimming. Our results suggest that shapes of some morphological features of living creatures, like the longitudinal ridges of the leatherback turtles, need not be streamlined for excellent hydro- or aerodynamic performances, contrary to our common physical intuition.
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Affiliation(s)
- Kyeongtae Bang
- Department of Mechanical & Aerospace Engineering, Seoul National University, Seoul, Korea
| | - Jooha Kim
- School of Mechanical and Nuclear Engineering, Ulsan National Institute of Science and Technology, Ulsan, Korea
| | - Sang-Im Lee
- Institute of Advanced Machines and Design, Seoul National University, Seoul, Korea
- Laboratory of Behavioral Ecology and Evolution, School of Biological Sciences, Seoul National University, Seoul, Korea
| | - Haecheon Choi
- Department of Mechanical & Aerospace Engineering, Seoul National University, Seoul, Korea
- Institute of Advanced Machines and Design, Seoul National University, Seoul, Korea
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11
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Van Wassenbergh S, van Manen K, Marcroft TA, Alfaro ME, Stamhuis EJ. Boxfish swimming paradox resolved: forces by the flow of water around the body promote manoeuvrability. J R Soc Interface 2015; 12:rsif.2014.1146. [PMID: 25505133 DOI: 10.1098/rsif.2014.1146] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The shape of the carapace protecting the body of boxfishes has been attributed an important hydrodynamic role in drag reduction and in providing automatic, flow-direction realignment and is therefore used in bioinspired design of cars. However, tight swimming-course stabilization is paradoxical given the frequent, high-performance manoeuvring that boxfishes display in their spatially complex, coral reef territories. Here, by performing flow-tank measurements of hydrodynamic drag and yaw moments together with computational fluid dynamics simulations, we reverse several assumptions about the hydrodynamic role of the boxfish carapace. Firstly, despite serving as a model system in aerodynamic design, drag-reduction performance was relatively low compared with more generalized fish morphologies. Secondly, the current theory of course stabilization owing to flow over the boxfish carapace was rejected, as destabilizing moments were found consistently. This solves the boxfish swimming paradox: destabilizing moments enhance manoeuvrability, which is in accordance with the ecological demands for efficient turning and tilting.
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Affiliation(s)
- S Van Wassenbergh
- Department of Biology, Universiteit Antwerpen, Universiteitsplein 1, 2610 Antwerpen, Belgium Evolutionar Morphology of Vertebrates, Ghent University, K.L. Ledeganckstraat 35, 9000 Gent, Belgium
| | - K van Manen
- Faculty of Mathematics and Natural Sciences, University of Groningen, Nijenborgh 7, AG Groningen 9747, The Netherlands
| | - T A Marcroft
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, 2154 Terasaki Life Sciences Building, Los Angeles, CA 90095, USA
| | - M E Alfaro
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, 2154 Terasaki Life Sciences Building, Los Angeles, CA 90095, USA
| | - E J Stamhuis
- Faculty of Mathematics and Natural Sciences, University of Groningen, Nijenborgh 7, AG Groningen 9747, The Netherlands Bionik Innovations Centrum, Hochschule Bremen, Neustadtswall 30, 28199 Bremen, Germany
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12
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Webb PW, Weihs D. Stability versus Maneuvering: Challenges for Stability during Swimming by Fishes. Integr Comp Biol 2015; 55:753-64. [PMID: 26002562 DOI: 10.1093/icb/icv053] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Fishes are well known for their remarkable maneuverability and agility. Less visible is the continuous control of stability essential for the exploitation of the full range of aquatic resources. Perturbations to posture and trajectory arise from hydrostatic and hydrodynamic forces centered in a fish (intrinsic) and from the environment (extrinsic). Hydrostatic instabilities arise from vertical and horizontal separation of the centers of mass (CM) and of buoyancy, thereby creating perturbations in roll, yaw, and pitch, with largely neglected implications for behavioral ecology. Among various forms of hydrodynamic stability, the need for stability in the face of recoil forces from propulsors is close to universal. Destabilizing torques in body-caudal fin swimming is created by inertial and viscous forces through a propulsor beat. The recoil component is reduced, damped, and corrected in various ways, including kinematics, shape of the body and fins, and deployment of the fins. We postulate that control of the angle of orientation, θ, of the trailing edge is especially important in the evolution and lifestyles of fishes, but studies are few. Control of stability and maneuvering are reflected in accelerations around the CM. Accelerations for such motions may give insight into time-behavior patterns in the wild but cannot be used to determine the expenditure of energy by free-swimming fishes.
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Affiliation(s)
- Paul W Webb
- *School of Natural Resources and Environment, University of Michigan, Ann Arbor, MI 48109, USA; Department of Aerospace Engineering and Autonomous Systems Program, Technion-Israel Institute of Technology, Haifa 32000, Israel
| | - Daniel Weihs
- *School of Natural Resources and Environment, University of Michigan, Ann Arbor, MI 48109, USA; Department of Aerospace Engineering and Autonomous Systems Program, Technion-Israel Institute of Technology, Haifa 32000, Israel
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14
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Rivera G, Rivera ARV, Blob RW. Hydrodynamic stability of the painted turtle (Chrysemys picta): effects of four-limbed rowing versus forelimb flapping in rigid-bodied tetrapods. ACTA ACUST UNITED AC 2011; 214:1153-62. [PMID: 21389201 DOI: 10.1242/jeb.046045] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Hydrodynamic stability is the ability to resist recoil motions of the body produced by destabilizing forces. Previous studies have suggested that recoil motions can decrease locomotor performance, efficiency and sensory perception and that swimming animals might utilize kinematic strategies or possess morphological adaptations that reduce recoil motions and produce more stable trajectories. We used high-speed video to assess hydrodynamic stability during rectilinear swimming in the freshwater painted turtle (Chrysemys picta). Parameters of vertical stability (heave and pitch) were non-cyclic and variable, whereas measures of lateral stability (sideslip and yaw) showed repeatable cyclic patterns. In addition, because freshwater and marine turtles use different swimming styles, we tested the effects of propulsive mode on hydrodynamic stability during rectilinear swimming, by comparing our data from painted turtles with previously collected data from two species of marine turtle (Caretta caretta and Chelonia mydas). Painted turtles had higher levels of stability than both species of marine turtle for six of the eight parameters tested, highlighting potential disadvantages associated with 'aquatic flight'. Finally, available data on hydrodynamic stability of other rigid-bodied vertebrates indicate that turtles are less stable than boxfish and pufferfish.
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Affiliation(s)
- Gabriel Rivera
- Department of Biological Sciences, Clemson University, 132 Long Hall, Clemson, SC 29634, USA.
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Da Silva EG, Gionfriddo JR, Powell CC, Campbell TW, Ehrhart EJ. CASE REPORT: Iridociliary melanoma with secondary lens luxation: distinctive findings in a long-horned cowfish (Lactoria cornuta). Vet Ophthalmol 2010; 13 Suppl:123-7. [DOI: 10.1111/j.1463-5224.2010.00804.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Blake RW. Biological implications of the hydrodynamics of swimming at or near the surface and in shallow water. BIOINSPIRATION & BIOMIMETICS 2009; 4:015004. [PMID: 19258689 DOI: 10.1088/1748-3182/4/1/015004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The origins and effects of wave drag at and near the surface and in shallow water are discussed in terms of the dispersive waves generated by streamlined technical bodies of revolution and by semi-aquatic and aquatic animals with a view to bearing on issues regarding the design and function of autonomous surface and underwater vehicles. A simple two-dimensional model based on energy flux, allowing assessment of drag and its associated wave amplitude, is applied to surface swimming in Lesser Scaup ducks and is in good agreement with measured values. It is argued that hydrodynamic limitations to swimming at speeds associated with the critical Froude number ( approximately 0.5) and hull speed do not necessarily set biological limitations as most behaviours occur well below the hull speed. From a comparative standpoint, the need for studies on the hull displacement of different forms is emphasized. For forms in surface proximity, drag is a function of both Froude and Reynolds numbers. Whilst the depth dependence of wave drag is not particularly sensitive to Reynolds number, its magnitude is, with smaller and slower forms subject to relatively less drag augmentation than larger, faster forms that generate additional resistance due to ventilation and spray. A quasi-steady approach to the hydrodynamics of swimming in shallow water identifies substantial drag increases relative to the deeply submerged case at Froude numbers of about 0.9 that could limit the performance of semi-aquatic and aquatic animals and autonomous vehicles. A comparative assessment of fast-starting trout and upside down catfish shows that the energy losses of fast-starting fish are likely to be less for fish in surface proximity in deep water than for those in shallow water. Further work on unsteady swimming in both circumstances is encouraged. Finally, perspectives are offered as to how autonomous surface and underwater vehicles in surface proximity and shallow water could function to avoid prohibitive hydrodynamic resistance, thereby increasing their operational life.
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Affiliation(s)
- R W Blake
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada.
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Blake RW, Ng H, Chan KHS, Li J. Fish and chips: implementation of a neural network model into computer chips to maximize swimming efficiency in autonomous underwater vehicles. BIOINSPIRATION & BIOMIMETICS 2008; 3:034002. [PMID: 18626130 DOI: 10.1088/1748-3182/3/3/034002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Recent developments in the design and propulsion of biomimetic autonomous underwater vehicles (AUVs) have focused on boxfish as models (e.g. Deng and Avadhanula 2005 Biomimetic micro underwater vehicle with oscillating fin propulsion: system design and force measurement Proc. 2005 IEEE Int. Conf. Robot. Auto. (Barcelona, Spain) pp 3312-7). Whilst such vehicles have many potential advantages in operating in complex environments (e.g. high manoeuvrability and stability), limited battery life and payload capacity are likely functional disadvantages. Boxfish employ undulatory median and paired fins during routine swimming which are characterized by high hydromechanical Froude efficiencies (approximately 0.9) at low forward speeds. Current boxfish-inspired vehicles are propelled by a low aspect ratio, 'plate-like' caudal fin (ostraciiform tail) which can be shown to operate at a relatively low maximum Froude efficiency (approximately 0.5) and is mainly employed as a rudder for steering and in rapid swimming bouts (e.g. escape responses). Given this and the fact that bioinspired engineering designs are not obligated to wholly duplicate a biological model, computer chips were developed using a multilayer perception neural network model of undulatory fin propulsion in the knifefish Xenomystus nigri that would potentially allow an AUV to achieve high optimum values of propulsive efficiency at any given forward velocity, giving a minimum energy drain on the battery. We envisage that externally monitored information on flow velocity (sensory system) would be conveyed to the chips residing in the vehicle's control unit, which in turn would signal the locomotor unit to adopt kinematics (e.g. fin frequency, amplitude) associated with optimal propulsion efficiency. Power savings could protract vehicle operational life and/or provide more power to other functions (e.g. communications).
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Affiliation(s)
- R W Blake
- Department of Zoology, University of British Columbia, British Columbia, V6T 1Z4, Canada.
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