1
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Camarillo H, Burress ED, Muñoz MM. Four-bar Geometry is Shared among Ecologically DivergentFish Species. Integr Org Biol 2024; 6:obae019. [PMID: 38949169 PMCID: PMC11211069 DOI: 10.1093/iob/obae019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Revised: 03/29/2024] [Indexed: 07/02/2024] Open
Abstract
Understanding the factors that influence morphological evolution is a major goal in biology. One such factor is the ability to acquire and process prey. Prey hardness and evasiveness are important properties that can impact evolution of the jaws. Similar diets and biomechanical systems have repeatedly evolved among fish lineages, providing an opportunity to test for shared patterns of evolution across distantly related organisms. Four-bar linkages are structures often used by animals to transmit force and motion during feeding and that provide an excellent system to understand the impact of diet on morphological and biomechanical evolution. Here, we tested how diet influences the evolutionary dynamics of the oral four-bar linkage system in wrasses (Family: Labridae) and cichlids (Family: Cichlidae). We found that shifts in prey hardness/evasiveness are associated with limited modifications in four-bar geometry across these two distantly related fish lineages. Wrasse and cichlid four-bar systems largely exhibit many-to-one mapping in response to dietary shifts. Across two iconic adaptive radiations of fish, an optimal four-bar geometry has largely been co-opted for different dietary functions during their extensive ecological diversification. Given the exceptional jaw diversity of both lineages, many-to-one mapping of morphology to mechanical properties may be a core feature of fish adaptive radiation.
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Affiliation(s)
- H Camarillo
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT 06510, USA
| | - E D Burress
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT 06510, USA
- Department of Biological Sciences, University of Alabama, Tuscaloosa, AL 35487, USA
| | - M M Muñoz
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT 06510, USA
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2
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Tetrault E, Aaronson B, Gilbert MC, Albertson RC. Foraging-induced craniofacial plasticity is associated with an early, robust and dynamic transcriptional response. Proc Biol Sci 2024; 291:20240215. [PMID: 38654651 PMCID: PMC11040245 DOI: 10.1098/rspb.2024.0215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2024] [Accepted: 03/19/2024] [Indexed: 04/26/2024] Open
Abstract
Phenotypic plasticity is the ability of a single genotype to vary its phenotype in response to the environment. Plasticity of the skeletal system in response to mechanical input is widely studied, but the timing of its transcriptional regulation is not well understood. Here, we used the cichlid feeding apparatus to examine the transcriptional dynamics of skeletal plasticity over time. Using three closely related species that vary in their ability to remodel bone and a panel of 11 genes, including well-studied skeletal differentiation markers and newly characterized environmentally sensitive genes, we examined plasticity at one, two, four and eight weeks following the onset of alternate foraging challenges. We found that the plastic species exhibited environment-specific bursts in gene expression beginning at one week, followed by a sharp decline in levels, while the species with more limited plasticity exhibited consistently low levels of gene expression. This trend held across nearly all genes, suggesting that it is a hallmark of the larger plasticity regulatory network. We conclude that plasticity of the cichlid feeding apparatus is not the result of slowly accumulating gene expression difference over time, but rather is stimulated by early bursts of environment-specific gene expression followed by a return to homeostatic levels.
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Affiliation(s)
- Emily Tetrault
- Molecular and Cell Biology Graduate Program, University of Massachusetts, Amherst, MA 01003, USA
| | - Ben Aaronson
- Department of Biology, University of Massachusetts, Amherst, MA 01003, USA
| | - Michelle C. Gilbert
- Department of Biology, Pennsylvania State University, State College, PA 16802, USA
| | - R. Craig Albertson
- Department of Biology, University of Massachusetts, Amherst, MA 01003, USA
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3
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Trotta F, Sandulli R, Cinquemani S. A Mechanical Approach for Comparing Jaws in Fishes. Biomimetics (Basel) 2024; 9:239. [PMID: 38667250 PMCID: PMC11047870 DOI: 10.3390/biomimetics9040239] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2024] [Revised: 04/02/2024] [Accepted: 04/10/2024] [Indexed: 04/28/2024] Open
Abstract
This paper aims to propose an quantitative engineering approach to study and compare the jaw mechanisms of different marine species, considering essential mechanical parameters generally used to evaluate the performance of industrial linkage mechanisms. By leveraging these parameters, the paper demonstrates how the species' characteristics and behaviors align with the findings of biologists, enabling a meaningful comparison that was not previously possible. Seven fish species from various families are chosen to maintain a generic approach.
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Affiliation(s)
- Federica Trotta
- Mechanical Engineering Department, Politecnico di Milano, Via Giuseppe La Masa, 1, 20156 Milan, Italy;
| | - Roberto Sandulli
- Department of Science and Technology (DiST), Consorzio Nazionale Interuniversitario per le Scienze del Mare (CoNISMa), Parthenope University of Naples, Centro Direzionale—Isola C4, 80143 Naples, Italy;
| | - Simone Cinquemani
- Mechanical Engineering Department, Politecnico di Milano, Via Giuseppe La Masa, 1, 20156 Milan, Italy;
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4
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Arbour J, Rumpp F, López-Fernández H. Organismal form constrains the evolution of complex lever systems in Neotropical cichlid four-bar linkages. Anat Rec (Hoboken) 2024; 307:81-96. [PMID: 37102462 DOI: 10.1002/ar.25231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2023] [Revised: 04/05/2023] [Accepted: 04/12/2023] [Indexed: 04/28/2023]
Abstract
The diversification of functional traits may be limited by the intrinsic constraints of organismal form (i.e., constructional constraints), owing to the differential investment in different anatomical structures. In this study, we test whether overall organismal form impacts the evolution of shape and function in complex lever systems. We examined the relationship between four-bar shape and overall head shape in two four-bar linkage systems: the oral-jaw and hyoid-neurocranium systems in Neotropical cichlids. We also investigated the strength of form-function mapping in these four-bar linkages and the impact of constraining head shape on these correlations. We quantified the shape of the head and two four-bar linkages using geometric morphometrics and compared these with the kinematic transmission coefficient of each linkage system. The shapes of both linkages were strongly correlated with their mechanical properties, and head shape appears to constrain the shape of both four-bar linkages. Head shape induced greater integration between the two linkages, was associated with stronger form-function correlations and higher rates of evolution in biomechanically important features. Head shape constraints may also contribute to a weak but significant trade-off in linkage kinematics. Elongation of the head and body, in particular, appears to minimize the impact of this trade-off, possibly through maximizing anterior-posterior space availability. However, the strength of relationships between shape and function, and the impact of head shape differed between the two linkages, with the hyoid four-bar in general showing stronger form-function relationships despite being more independent from head shape constraints.
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Affiliation(s)
- Jessica Arbour
- Department of Biology, Middle Tennessee State University, Murfreesboro, Tennessee, USA
| | - Faith Rumpp
- Department of Biology, Middle Tennessee State University, Murfreesboro, Tennessee, USA
| | - Hernán López-Fernández
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, Michigan, USA
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5
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Anderson PSL. Shifts in morphological covariation and evolutionary rates across multiple acquisitions of the trap-jaw mechanism in Strumigenys. Evolution 2022; 76:2076-2088. [PMID: 35848877 PMCID: PMC9545230 DOI: 10.1111/evo.14557] [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] [Received: 09/29/2021] [Revised: 05/11/2022] [Accepted: 06/21/2022] [Indexed: 01/22/2023]
Abstract
A long-standing question in comparative biology is how the evolution of biomechanical systems influences morphological evolution. The need for functional fidelity implies that the evolution of such systems should be associated with tighter morphological covariation, which may promote or dampen rates of morphological evolution. I examine this question across multiple evolutionary origins of the trap-jaw mechanism in the genus Strumigenys. Trap-jaw ants have latch-mediated, spring-actuated systems that amplify the power output of their mandibles. I use Bayesian estimates of covariation and evolutionary rates to test the hypotheses that the evolution of this high-performance system is associated with tighter morphological covariation in the head and mandibles relative to nontrap-jaw forms and that this leads to shifts in rates of morphological evolution. Contrary to these hypotheses, there is no evidence of a large-scale shift to higher covariation in trap-jaw forms, while different traits show both increased and decreased evolutionary rates between forms. These patterns may be indicative of many-to-one mapping and/or mechanical sensitivity in the trap-jaw LaMSA system. Overall, it appears that the evolution of trap-jaw forms in Strumigenys did not require a correlated increase in morphological covariation, partly explaining the proclivity with which the system has evolved.
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Affiliation(s)
- Philip S. L. Anderson
- Department of EvolutionEcology and Behavior, University of IllinoisUrbana Champaign, 515 Morrill Hall, 505 S Goodwin AveUrbanaIL61801
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6
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Cook A, Pandhigunta K, Acevedo MA, Walker A, Didcock RL, Castro JT, O’Neill D, Acharya R, Bhamla MS, Anderson PSL, Ilton M. A Tunable, Simplified Model for Biological Latch Mediated Spring Actuated Systems. Integr Org Biol 2022; 4:obac032. [PMID: 36060863 PMCID: PMC9434652 DOI: 10.1093/iob/obac032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Revised: 06/01/2022] [Accepted: 07/26/2022] [Indexed: 11/24/2022] Open
Abstract
We develop a model of latch-mediated spring actuated (LaMSA) systems relevant to comparative biomechanics and bioinspired design. The model contains five components: two motors (muscles), a spring, a latch, and a load mass. One motor loads the spring to store elastic energy and the second motor subsequently removes the latch, which releases the spring and causes movement of the load mass. We develop freely available software to accompany the model, which provides an extensible framework for simulating LaMSA systems. Output from the simulation includes information from the loading and release phases of motion, which can be used to calculate kinematic performance metrics that are important for biomechanical function. In parallel, we simulate a comparable, directly actuated system that uses the same motor and mass combinations as the LaMSA simulations. By rapidly iterating through biologically relevant input parameters to the model, simulated kinematic performance differences between LaMSA and directly actuated systems can be used to explore the evolutionary dynamics of biological LaMSA systems and uncover design principles for bioinspired LaMSA systems. As proof of principle of this concept, we compare a LaMSA simulation to a directly actuated simulation that includes either a Hill-type force-velocity trade-off or muscle activation dynamics, or both. For the biologically-relevant range of parameters explored, we find that the muscle force-velocity trade-off and muscle activation have similar effects on directly actuated performance. Including both of these dynamic muscle properties increases the accelerated mass range where a LaMSA system outperforms a directly actuated one.
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Affiliation(s)
- Andrés Cook
- Department of Physics, Harvey Mudd College, Claremont, CA 91711
| | | | - Mason A Acevedo
- Department of Physics, Harvey Mudd College, Claremont, CA 91711
| | - Adam Walker
- Department of Physics, Harvey Mudd College, Claremont, CA 91711
| | | | | | - Declan O’Neill
- Department of Physics, Harvey Mudd College, Claremont, CA 91711
| | - Raghav Acharya
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia 30318
| | - M Saad Bhamla
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia 30318
| | - Philip S L Anderson
- Department of Evolution, Ecology, and Behavior, University of Illinois at Urbana-Champaign, Urbana, IL 61801
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7
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A physical model of mantis shrimp for exploring the dynamics of ultrafast systems. Proc Natl Acad Sci U S A 2021; 118:2026833118. [PMID: 34389671 DOI: 10.1073/pnas.2026833118] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Efficient and effective generation of high-acceleration movement in biology requires a process to control energy flow and amplify mechanical power from power density-limited muscle. Until recently, this ability was exclusive to ultrafast, small organisms, and this process was largely ascribed to the high mechanical power density of small elastic recoil mechanisms. In several ultrafast organisms, linkages suddenly initiate rotation when they overcenter and reverse torque; this process mediates the release of stored elastic energy and enhances the mechanical power output of extremely fast, spring-actuated systems. Here we report the discovery of linkage dynamics and geometric latching that reveals how organisms and synthetic systems generate extremely high-acceleration, short-duration movements. Through synergistic analyses of mantis shrimp strikes, a synthetic mantis shrimp robot, and a dynamic mathematical model, we discover that linkages can exhibit distinct dynamic phases that control energy transfer from stored elastic energy to ultrafast movement. These design principles are embodied in a 1.5-g mantis shrimp scale mechanism capable of striking velocities over 26 m [Formula: see text] in air and 5 m [Formula: see text] in water. The physical, mathematical, and biological datasets establish latching mechanics with four temporal phases and identify a nondimensional performance metric to analyze potential energy transfer. These temporal phases enable control of an extreme cascade of mechanical power amplification. Linkage dynamics and temporal phase characteristics are easily adjusted through linkage design in robotic and mathematical systems and provide a framework to understand the function of linkages and latches in biological systems.
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8
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Müller UK, Poppinga S. Form, Structure, and Function: How Plants vs. Animals Solve Physical Problems. Integr Comp Biol 2020; 60:815-819. [PMID: 33141898 DOI: 10.1093/icb/icaa118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Plants and animals have evolved solutions for a wide range of mechanical problems, such as adhesion and dispersal. Several of these solutions have been sources for bio-inspiration, like the Lotus Effect for self-cleaning surfaces or Velcro for adhesion. This symposium brought together plant and animal biomechanics researchers who tackle similar problems in different systems under the unifying theme of structure-function relations with relevance to bio-inspiration. For both communities it holds true that the structural systems, which have evolved in the respective organisms to address the mechanical challenges mentioned above, are often highly complex. This requires interdisciplinary research involving "classical" experimental biology approaches in combination with advanced imaging methods and computational modeling. The transfer of such systems into biomimetic technical materials and structures comes with even more challenges, like scalability issues and applicability. Having brought all these topics under one umbrella, this symposium presented the forefront of biophysical basic and application-oriented international research with the goal of facilitation knowledge transfer across systems and disciplines.
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Affiliation(s)
- Ulrike K Müller
- Department of Biology, California State University Fresno, Fresno, California USA
| | - Simon Poppinga
- Plant Biomechanics Group, Botanic Garden, University of Freiburg, Freiburg im Breisgau, Germany.,Freiburg Materials Research Center (FMF), University of Freiburg, Freiburg im Breisgau, Germany
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9
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Anderson PSL, Rivera MD, Suarez AV. "Simple" Biomechanical Model for Ants Reveals How Correlated Evolution among Body Segments Minimizes Variation in Center of Mass as Heads Get Larger. Integr Comp Biol 2020; 60:1193-1207. [PMID: 32386301 DOI: 10.1093/icb/icaa027] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The field of comparative biomechanics strives to understand the diversity of the biological world through the lens of physics. To accomplish this, researchers apply a variety of modeling approaches to explore the evolution of form and function ranging from basic lever models to intricate computer simulations. While advances in technology have allowed for increasing model complexity, insight can still be gained through the use of low-parameter "simple" models. All models, regardless of complexity, are simplifications of reality and must make assumptions; "simple" models just make more assumptions than complex ones. However, "simple" models have several advantages. They allow individual parameters to be isolated and tested systematically, can be made applicable to a wide range of organisms and make good starting points for comparative studies, allowing for complexity to be added as needed. To illustrate these ideas, we perform a case study on body form and center of mass stability in ants. Ants show a wide diversity of body forms, particularly in terms of the relative size of the head, petiole(s), and gaster (the latter two make-up the segments of the abdomen not fused to thorax in hymenopterans). We use a "simple" model to explore whether balance issues pertaining to the center of mass influence patterns of segment expansion across major ant clades. Results from phylogenetic comparative methods imply that the location of the center of mass in an ant's body is under stabilizing selection, constraining the center of mass to the middle segment (thorax) over the legs. This is potentially maintained by correlated rates of evolution between the head and gaster on either end. While these patterns arise from a model that makes several assumptions/simplifications relating to shape and materials, they still offer intriguing insights into the body plan of ants across ∼68% of their diversity. The results from our case study illustrate how "simple," low-parameter models both highlight fundamental biomechanical trends and aid in crystalizing specific questions and hypotheses for more complex models to address.
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Affiliation(s)
- Philip S L Anderson
- Department of Evolution, Ecology and Behavior, University of Illinois, Urbana-Champaign, IL, USA.,Program in Ecology, Evolution, and Conservation Biology, University of Illinois, Urbana-Champaign, IL, USA.,Beckman Institute for Science and Technology, University of Illinois, Urbana-Champaign, IL, USA
| | - Michael D Rivera
- Program in Ecology, Evolution, and Conservation Biology, University of Illinois, Urbana-Champaign, IL, USA
| | - Andrew V Suarez
- Department of Evolution, Ecology and Behavior, University of Illinois, Urbana-Champaign, IL, USA.,Program in Ecology, Evolution, and Conservation Biology, University of Illinois, Urbana-Champaign, IL, USA.,Beckman Institute for Science and Technology, University of Illinois, Urbana-Champaign, IL, USA.,Department of Entomology, University of Illinois, Urbana-Champaign, IL, USA
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10
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Patek SN. The Power of Mantis Shrimp Strikes: Interdisciplinary Impacts of an Extreme Cascade of Energy Release. Integr Comp Biol 2020; 59:1573-1585. [PMID: 31304967 DOI: 10.1093/icb/icz127] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
In the course of a single raptorial strike by a mantis shrimp (Stomatopoda), the stages of energy release span six to seven orders of magnitude of duration. To achieve their mechanical feats of striking at the outer limits of speeds, accelerations, and impacts among organisms, they use a mechanism that exemplifies a cascade of energy release-beginning with a slow and forceful, spring-loading muscle contraction that lasts for hundreds of milliseconds and ending with implosions of cavitation bubbles that occur in nanoseconds. Mantis shrimp use an elastic mechanism built of exoskeleton and controlled with a latching mechanism. Inspired by both their mechanical capabilities and evolutionary diversity, research on mantis shrimp strikes has provided interdisciplinary and fundamental insights to the fields of elastic mechanisms, fluid dynamics, evolutionary dynamics, contest dynamics, the physics of fast, small systems, and the rapidly-expanding field of bioinspired materials science. Even with these myriad connections, numerous discoveries await, especially in the arena of energy flow through materials actuating and controlling fast, impact fracture resistant systems.
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Affiliation(s)
- S N Patek
- Biology Department, Duke University, Durham, NC, USA
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11
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St John ME, Holzman R, Martin CH. Rapid adaptive evolution of scale-eating kinematics to a novel ecological niche. J Exp Biol 2020; 223:jeb217570. [PMID: 32029459 PMCID: PMC7097200 DOI: 10.1242/jeb.217570] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Accepted: 01/29/2020] [Indexed: 01/08/2023]
Abstract
The origins of novel trophic specialization, in which organisms begin to exploit resources for the first time, may be explained by shifts in behavior such as foraging preferences or feeding kinematics. One way to investigate behavioral mechanisms underlying ecological novelty is by comparing prey capture kinematics among species. We investigated the contribution of kinematics to the origins of a novel ecological niche for scale-eating within a microendemic adaptive radiation of pupfishes on San Salvador Island, Bahamas. We compared prey capture kinematics across three species of pupfish while they consumed shrimp and scales in the lab, and found that scale-eating pupfish exhibited peak gape sizes twice as large as in other species, but also attacked prey with a more obtuse angle between their lower jaw and suspensorium. We then investigated how this variation in feeding kinematics could explain scale-biting performance by measuring bite size (surface area removed) from standardized gelatin cubes. We found that a combination of larger peak gape and more obtuse lower jaw and suspensorium angles resulted in approximately 40% more surface area removed per strike, indicating that scale-eaters may reside on a performance optimum for scale biting. To test whether feeding performance could contribute to reproductive isolation between species, we also measured F1 hybrids and found that their kinematics and performance more closely resembled generalists, suggesting that F1 hybrids may have low fitness in the scale-eating niche. Ultimately, our results suggest that the evolution of strike kinematics in this radiation is an adaptation to the novel niche of scale eating.
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Affiliation(s)
- Michelle E St John
- Department of Integrative Biology, University of California, Berkeley, Berkeley, CA 94720, USA
- Museum of Vertebrate Zoology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Roi Holzman
- School of Zoology, Tel Aviv University, Eilat 6997801, Israel
- Inter-University Institute for Marine Sciences, Eilat 8810302, Israel
| | - Christopher H Martin
- Department of Integrative Biology, University of California, Berkeley, Berkeley, CA 94720, USA
- Museum of Vertebrate Zoology, University of California, Berkeley, Berkeley, CA 94720, USA
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12
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Abstract
Animals use a diverse array of motion to feed, escape predators, and reproduce. Linking morphology, performance, and fitness is a foundational paradigm in organismal biology and evolution. Yet, the influence of mechanical relationships on evolutionary diversity remains unresolved. Here, I focus on the many-to-one mapping of form to function, a widespread, emergent property of many mechanical systems in nature, and discuss how mechanical redundancy influences the tempo and mode of phenotypic evolution. By supplying many possible morphological pathways for functional adaptation, many-to-one mapping can release morphology from selection on performance. Consequently, many-to-one mapping decouples morphological and functional diversification. In fish, for example, parallel morphological evolution is weaker for traits that contribute to mechanically redundant motions, like suction feeding performance, than for systems with one-to-one form-function relationships, like lower jaw lever ratios. As mechanical complexity increases, historical factors play a stronger role in shaping evolutionary trajectories. Many-to-one mapping, however, does not always result in equal freedom of morphological evolution. The kinematics of complex systems can often be reduced to variation in a few traits of high mechanical effect. In various different four-bar linkage systems, for example, mechanical output (kinematic transmission) is highly sensitive to size variation in one or two links, and insensitive to variation in the others. In four-bar linkage systems, faster rates of evolution are biased to traits of high mechanical effect. Mechanical sensitivity also results in stronger parallel evolution-evolutionary transitions in mechanical output are coupled with transition in linkages of high mechanical effect. In other words, the evolutionary dynamics of complex systems can actually approximate that of simpler, one-to-one systems when mechanical sensitivity is strong. When examined in a macroevolutionary framework, the same mechanical system may experience distinct selective pressures in different groups of organisms. For example, performance tradeoffs are stronger for organisms that use the same mechanical structure for more functions. In general, stronger performance tradeoffs result in less phenotypic diversity in the system and, sometimes, a slower rate of evolution. These macroevolutionary trends can contribute to unevenness in functional and lineage diversity across the tree of life. Finally, I discuss how the evolution of mechanical systems informs our understanding of the relative roles of determinism and contingency in evolution.
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Affiliation(s)
- Martha M Muñoz
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA 24060, USA
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13
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Hulsey CD, Alfaro ME, Zheng J, Meyer A, Holzman R. Pleiotropic jaw morphology links the evolution of mechanical modularity and functional feeding convergence in Lake Malawi cichlids. Proc Biol Sci 2019; 286:20182358. [PMID: 30963830 PMCID: PMC6408893 DOI: 10.1098/rspb.2018.2358] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Accepted: 02/01/2019] [Indexed: 12/12/2022] Open
Abstract
Complexity in how mechanistic variation translates into ecological novelty could be critical to organismal diversification. For instance, when multiple distinct morphologies can generate the same mechanical or functional phenotype, this could mitigate trade-offs and/or provide alternative ways to meet the same ecological challenge. To investigate how this type of complexity shapes diversity in a classic adaptive radiation, we tested several evolutionary consequences of the anterior jaw four-bar linkage for Lake Malawi cichlid trophic diversification. Using a novel phylogenetic framework, we demonstrated that different mechanical outputs of the same four jaw elements are evolutionarily associated with both jaw protrusion distance and jaw protrusion angle. However, these two functional aspects of jaw protrusion have evolved independently. Additionally, although four-bar morphology showed little evidence for attraction to optima, there was substantial evidence of adaptive peaks for emergent four-bar linkage mechanics and jaw protrusion abilities among Malawi feeding guilds. Finally, we highlighted a clear case of two cichlid species that have -independently evolved to graze algae in less than 2 Myr and have converged on similar jaw protrusion abilities as well as four-bar linkage mechanics, but have evolved these similarities via non-convergent four-bar morphologies.
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Affiliation(s)
- C. Darrin Hulsey
- Department of Biology, Universität Konstanz, Universitätsstraße 10, 78457 Konstanz, Germany
| | - Michael E. Alfaro
- Department of Ecology & Evolutionary Biology, University of California-Los Angeles, 610 Charles E. Young Drive East, Los Angeles, CA 90095-7246, USA
| | - Jimmy Zheng
- Department of Ecology & Evolutionary Biology, University of California-Los Angeles, 610 Charles E. Young Drive East, Los Angeles, CA 90095-7246, USA
| | - Axel Meyer
- Department of Biology, Universität Konstanz, Universitätsstraße 10, 78457 Konstanz, Germany
| | - Roi Holzman
- Department of Zoology, Tel Aviv University and the Inter-University Institute for Marine Sciences, PO Box 469, Eilat 88103, Israel
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14
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Baumgart A, Anderson P. Finding the weakest link: mechanical sensitivity in a fish cranial linkage system. ROYAL SOCIETY OPEN SCIENCE 2018; 5:181003. [PMID: 30473846 PMCID: PMC6227944 DOI: 10.1098/rsos.181003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Accepted: 09/11/2018] [Indexed: 06/09/2023]
Abstract
Understanding the physical mechanics behind morphological systems can offer insights into their evolution. Recent work on linkage systems in fish and crustaceans has suggested that the evolution of such systems may depend on mechanical sensitivity, where geometrical changes to different parts of a biomechanical system have variable influence on mechanical outputs. While examined at the evolutionary level, no study has directly explored this idea at the level of the mechanism. We analyse the mechanical sensitivity of a fish cranial linkage to identify the influence of linkage geometry on the kinematic transmission (KT) of the suspensorium, hyoid and lower jaw. Specifically, we answer two questions about the sensitivity of this linkage system: (i) What changes in linkage geometry affect one KT while keeping the other KTs constant? (ii) Which geometry changes result in the largest and smallest changes to KT? Our results show that there are ways to alter the morphology that change each KT individually, and that there are multiple ways to alter a single link that have variable influence on KT. These results provide insight into the morphological evolution of the fish skull and highlight which structural features in the system may have more freedom to evolve than others.
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Affiliation(s)
- A. Baumgart
- Department of Mechanical Science and Engineering, University of Illinois, Urbana, IL 61801, USA
| | - P. Anderson
- Department of Animal Biology, University of Illinois, Urbana, IL 61801, USA
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15
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Muñoz MM, Hu Y, Anderson PSL, Patek SN. Strong biomechanical relationships bias the tempo and mode of morphological evolution. eLife 2018; 7:e37621. [PMID: 30091704 PMCID: PMC6133543 DOI: 10.7554/elife.37621] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Accepted: 08/08/2018] [Indexed: 12/17/2022] Open
Abstract
The influence of biomechanics on the tempo and mode of morphological evolution is unresolved, yet is fundamental to organismal diversification. Across multiple four-bar linkage systems in animals, we discovered that rapid morphological evolution (tempo) is associated with mechanical sensitivity (strong correlation between a mechanical system's output and one or more of its components). Mechanical sensitivity is explained by size: the smallest link(s) are disproportionately affected by length changes and most strongly influence mechanical output. Rate of evolutionary change (tempo) is greatest in the smallest links and trait shifts across phylogeny (mode) occur exclusively via the influential, small links. Our findings illuminate the paradigms of many-to-one mapping, mechanical sensitivity, and constraints: tempo and mode are dominated by strong correlations that exemplify mechanical sensitivity, even in linkage systems known for exhibiting many-to-one mapping. Amidst myriad influences, mechanical sensitivity imparts distinct, predictable footprints on morphological diversity.
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Affiliation(s)
- Martha M Muñoz
- Department of Biological SciencesVirginia TechBlacksburgUnited States
- Department of BiologyDuke UniversityDurhamUnited States
| | - Y Hu
- Department of Biological SciencesUniversity of Rhode IslandKingstonUnited States
| | - Philip S L Anderson
- Department of Animal BiologyUniversity of IllinoisUrbana-ChampaignUnited States
| | - SN Patek
- Department of BiologyDuke UniversityDurhamUnited States
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