1
|
Gómez RO, Lois-Milevicich J. Comparative osteology of the skull of cowbirds (Icteridae: Molothrus). J Morphol 2024; 285:e21752. [PMID: 39016160 DOI: 10.1002/jmor.21752] [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: 05/24/2024] [Revised: 07/01/2024] [Accepted: 07/09/2024] [Indexed: 07/18/2024]
Abstract
Detailed osteological descriptions of the craniomandibular complex of passerine birds are lacking for most species, limiting our understanding of their diversity and evolution. Cowbirds (genus Molothrus) are a small but widespread group of New World nine-primaried songbirds, well-known for their unique brooding parasitic behavior. However, detailed osteological data for cowbirds and other Icteridae are currently scarce and several features of their skulls remain undescribed or poorly known. To address this issue, a detailed comparative osteology of cowbird skulls is presented here for the first time based on data from x-ray microcomputed tomography, dry skeletal data, and multivariate analyses of linear morphometric data. Cowbird skulls offer some functional insights, with many finch-like features probably related to a seed-rich diet that distinguishes them from most other icterids. In addition, features previously overlooked in earlier studies might provide valuable phylogenetic information at different levels of passerine phylogeny (Passerida, Emberizoidea, Icteridae, and Agelaiinae), including some of the otic region and nasal septum. Comparisons among cowbirds show that there is substantial cranial variation within the genus, with M. oryzivorus being the most divergent cowbird species. Within the genus, distantly related species share similar overall skull morphology and proportions, but detailed osteological data allow species identification even in cases of strong convergence. Further efforts are warranted to furnish baseline data for future studies of this iconic group of Neotropical birds and to fully integrate it into phylogenetic comparative frameworks.
Collapse
Affiliation(s)
- Raúl O Gómez
- CONICET-Departamento de Biodiversidad y Biología Experimental, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Pabellón II Ciudad Universitaria, Buenos Aires, Argentina
| | - Jimena Lois-Milevicich
- CONICET-Departamento de Ecología, Genética y Evolución, Instituto de Ecología, Genética y Evolución (IEGEBA-CONICET), Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Pabellón II Ciudad Universitaria, Buenos Aires, Argentina
| |
Collapse
|
2
|
Herrick J. DNA Damage, Genome Stability, and Adaptation: A Question of Chance or Necessity? Genes (Basel) 2024; 15:520. [PMID: 38674454 PMCID: PMC11049855 DOI: 10.3390/genes15040520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2024] [Revised: 04/14/2024] [Accepted: 04/18/2024] [Indexed: 04/28/2024] Open
Abstract
DNA damage causes the mutations that are the principal source of genetic variation. DNA damage detection and repair mechanisms therefore play a determining role in generating the genetic diversity on which natural selection acts. Speciation, it is commonly assumed, occurs at a rate set by the level of standing allelic diversity in a population. The process of speciation is driven by a combination of two evolutionary forces: genetic drift and ecological selection. Genetic drift takes place under the conditions of relaxed selection, and results in a balance between the rates of mutation and the rates of genetic substitution. These two processes, drift and selection, are necessarily mediated by a variety of mechanisms guaranteeing genome stability in any given species. One of the outstanding questions in evolutionary biology concerns the origin of the widely varying phylogenetic distribution of biodiversity across the Tree of Life and how the forces of drift and selection contribute to shaping that distribution. The following examines some of the molecular mechanisms underlying genome stability and the adaptive radiations that are associated with biodiversity and the widely varying species richness and evenness in the different eukaryotic lineages.
Collapse
Affiliation(s)
- John Herrick
- Independent Researcher at 3, Rue des Jeûneurs, 75002 Paris, France
| |
Collapse
|
3
|
Sansalone G, Wroe S, Coates G, Attard MRG, Fruciano C. Unexpectedly uneven distribution of functional trade-offs explains cranial morphological diversity in carnivores. Nat Commun 2024; 15:3275. [PMID: 38627430 PMCID: PMC11021405 DOI: 10.1038/s41467-024-47620-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Accepted: 04/08/2024] [Indexed: 04/19/2024] Open
Abstract
Functional trade-offs can affect patterns of morphological and ecological evolution as well as the magnitude of morphological changes through evolutionary time. Using morpho-functional landscape modelling on the cranium of 132 carnivore species, we focused on the macroevolutionary effects of the trade-off between bite force and bite velocity. Here, we show that rates of evolution in form (morphology) are decoupled from rates of evolution in function. Further, we found theoretical morphologies optimising for velocity to be more diverse, while a much smaller phenotypic space was occupied by shapes optimising force. This pattern of differential representation of different functions in theoretical morphological space was highly correlated with patterns of actual morphological disparity. We hypothesise that many-to-one mapping of cranium shape on function may prevent the detection of direct relationships between form and function. As comparatively only few morphologies optimise bite force, species optimising this function may be less abundant because they are less likely to evolve. This, in turn, may explain why certain clades are less variable than others. Given the ubiquity of functional trade-offs in biological systems, these patterns may be general and may help to explain the unevenness of morphological and functional diversity across the tree of life.
Collapse
Affiliation(s)
- Gabriele Sansalone
- Institute for Marine Biological Resources and Biotechnology (CNR-IRBIM), National Research Council, Via S. Raineri 4, 98122, Messina, Italy.
- Function, Evolution and Anatomy Research Lab, Zoology Division, School of Environmental and Rural Science, University of New England, Armidale, NSW, Australia.
- Department of Life Sciences, University of Modena and Reggio Emilia, Via Campi 213D, 41125, Modena, Italy.
| | - Stephen Wroe
- Function, Evolution and Anatomy Research Lab, Zoology Division, School of Environmental and Rural Science, University of New England, Armidale, NSW, Australia
| | - Geoffrey Coates
- Function, Evolution and Anatomy Research Lab, Zoology Division, School of Environmental and Rural Science, University of New England, Armidale, NSW, Australia
| | - Marie R G Attard
- Function, Evolution and Anatomy Research Lab, Zoology Division, School of Environmental and Rural Science, University of New England, Armidale, NSW, Australia
- British Antarctic Survey, High Cross, Madingley Road, CB3 0ET, Cambridge, UK
| | - Carmelo Fruciano
- Institute for Marine Biological Resources and Biotechnology (CNR-IRBIM), National Research Council, Via S. Raineri 4, 98122, Messina, Italy.
- National Biodiversity Future Center, Piazza Marina 61, 90133, Palermo, Italy.
- Department of Biological, Geological and Environmental Sciences, University of Catania, via Androne 81, 95124, Catania, Italy.
| |
Collapse
|
4
|
Mitchell DR, Sherratt E, Weisbecker V. Facing the facts: adaptive trade-offs along body size ranges determine mammalian craniofacial scaling. Biol Rev Camb Philos Soc 2024; 99:496-524. [PMID: 38029779 DOI: 10.1111/brv.13032] [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: 03/27/2023] [Revised: 11/12/2023] [Accepted: 11/14/2023] [Indexed: 12/01/2023]
Abstract
The mammalian cranium (skull without lower jaw) is representative of mammalian diversity and is thus of particular interest to mammalian biologists across disciplines. One widely retrieved pattern accompanying mammalian cranial diversification is referred to as 'craniofacial evolutionary allometry' (CREA). This posits that adults of larger species, in a group of closely related mammals, tend to have relatively longer faces and smaller braincases. However, no process has been officially suggested to explain this pattern, there are many apparent exceptions, and its predictions potentially conflict with well-established biomechanical principles. Understanding the mechanisms behind CREA and causes for deviations from the pattern therefore has tremendous potential to explain allometry and diversification of the mammalian cranium. Here, we propose an amended framework to characterise the CREA pattern more clearly, in that 'longer faces' can arise through several kinds of evolutionary change, including elongation of the rostrum, retraction of the jaw muscles, or a more narrow or shallow skull, which all result in a generalised gracilisation of the facial skeleton with increased size. We define a standardised workflow to test for the presence of the pattern, using allometric shape predictions derived from geometric morphometrics analysis, and apply this to 22 mammalian families including marsupials, rabbits, rodents, bats, carnivores, antelopes, and whales. Our results show that increasing facial gracility with size is common, but not necessarily as ubiquitous as previously suggested. To address the mechanistic basis for this variation, we then review cranial adaptations for harder biting. These dictate that a more gracile cranium in larger species must represent a structural sacrifice in the ability to produce or withstand harder bites, relative to size. This leads us to propose that facial gracilisation in larger species is often a product of bite force allometry and phylogenetic niche conservatism, where more closely related species tend to exhibit more similar feeding ecology and biting behaviours and, therefore, absolute (size-independent) bite force requirements. Since larger species can produce the same absolute bite forces as smaller species with less effort, we propose that relaxed bite force demands can permit facial gracility in response to bone optimisation and alternative selection pressures. Thus, mammalian facial scaling represents an adaptive by-product of the shifting importance of selective pressures occurring with increased size. A reverse pattern of facial 'shortening' can accordingly also be found, and is retrieved in several cases here, where larger species incorporate novel feeding behaviours involving greater bite forces. We discuss multiple exceptions to a bite force-mediated influence on facial proportions across mammals which lead us to argue that ecomorphological specialisation of the cranium is likely to be the primary driver of facial scaling patterns, with some developmental constraints as possible secondary factors. A potential for larger species to have a wider range of cranial functions when less constrained by bite force demands might also explain why selection for larger sizes seems to be prevalent in some mammalian clades. The interplay between adaptation and constraint across size ranges thus presents an interesting consideration for a mechanistically grounded investigation of mammalian cranial allometry.
Collapse
Affiliation(s)
- D Rex Mitchell
- College of Science and Engineering, Flinders University, GPO Box 2100, Adelaide, South Australia, 5001, Australia
- Australian Research Council Centre of Excellence for Australian Biodiversity and Heritage, Wollongong, New South Wales, 2522, Australia
| | - Emma Sherratt
- School of Biological Sciences, The University of Adelaide, Adelaide, South Australia, 5005, Australia
- South Australian Museum, Adelaide, South Australia, 5000, Australia
| | - Vera Weisbecker
- College of Science and Engineering, Flinders University, GPO Box 2100, Adelaide, South Australia, 5001, Australia
- Australian Research Council Centre of Excellence for Australian Biodiversity and Heritage, Wollongong, New South Wales, 2522, Australia
| |
Collapse
|
5
|
Serra F, Balseiro D, Monnet C, Randolfe E, Bignon A, Rustán JJ, Bault V, Muñoz DF, Vaccari NE, Martinetto M, Crônier C, Waisfeld BG. A dynamic and collaborative database for morphogeometric information of trilobites. Sci Data 2023; 10:841. [PMID: 38030629 PMCID: PMC10687081 DOI: 10.1038/s41597-023-02724-9] [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: 06/14/2023] [Accepted: 11/06/2023] [Indexed: 12/01/2023] Open
Abstract
Modern morphometric-based approaches provide valuable metrics to quantify and understand macroevolutionary and macroecological patterns and processes. Here we describe TriloMorph, an openly accessible database for morpho-geometric information of trilobites, together with a landmark acquisition protocol. In addition to morphological traits, the database contains contextual data on chronostratigraphic age, geographic location, taxonomic information and lithology of landmarked specimens. In this first version, the dataset has broad taxonomic and temporal coverage and comprises more than 55% of all trilobite genera and 85% of families recorded in the Paleobiology Database through the Devonian. We provide a release of geometric morphometric data of 277 specimens linked to published references. Additionally, we established a Github repository for constant input of morphometric data by multiple contributors and present R functions that help with data retrieval and analysis. This is the first attempt of an online, dynamic and collaborative morphometric repository. By bringing this information into a single open database we enhance the possibility of performing global palaeobiological research, providing a major complement to current occurrence-based databases.
Collapse
Affiliation(s)
- Fernanda Serra
- Universidad Nacional de Córdoba, Facultad de Ciencias Exactas Físicas y Naturales, Córdoba, Argentina
- CICTERRA (Centro de Investigaciones en Ciencias de la Tierra), CONICET, Córdoba, Argentina
| | - Diego Balseiro
- Universidad Nacional de Córdoba, Facultad de Ciencias Exactas Físicas y Naturales, Córdoba, Argentina
- CICTERRA (Centro de Investigaciones en Ciencias de la Tierra), CONICET, Córdoba, Argentina
| | - Claude Monnet
- Univ. Lille, CNRS, UMR 8198 - Evo-Eco-Paleo, F-59000, Lille, France
| | - Enrique Randolfe
- Universidad Nacional de Córdoba, Facultad de Ciencias Exactas Físicas y Naturales, Córdoba, Argentina
- CICTERRA (Centro de Investigaciones en Ciencias de la Tierra), CONICET, Córdoba, Argentina
| | - Arnaud Bignon
- Universidad Nacional de Córdoba, Facultad de Ciencias Exactas Físicas y Naturales, Córdoba, Argentina
- CICTERRA (Centro de Investigaciones en Ciencias de la Tierra), CONICET, Córdoba, Argentina
| | - Juan J Rustán
- Universidad Nacional de Córdoba, Facultad de Ciencias Exactas Físicas y Naturales, Córdoba, Argentina
- CICTERRA (Centro de Investigaciones en Ciencias de la Tierra), CONICET, Córdoba, Argentina
| | - Valentin Bault
- Univ. Lille, CNRS, UMR 8198 - Evo-Eco-Paleo, F-59000, Lille, France
| | - Diego F Muñoz
- IIMYC (Instituto de Investigaciones Marinas y Costeras), CONICET - Universidad Nacional de Mar del Plata, Mar del Plata, Argentina
- IGCyC (Instituto de Geología de Costas y del Cuaternario), Universidad Nacional de Mar del Plata - CIC PBA, Mar del Plata, Argentina
| | - N Emilio Vaccari
- Universidad Nacional de Córdoba, Facultad de Ciencias Exactas Físicas y Naturales, Córdoba, Argentina
- CICTERRA (Centro de Investigaciones en Ciencias de la Tierra), CONICET, Córdoba, Argentina
| | - Malena Martinetto
- Universidad Nacional de Córdoba, Facultad de Ciencias Exactas Físicas y Naturales, Córdoba, Argentina
| | - Catherine Crônier
- Univ. Lille, CNRS, UMR 8198 - Evo-Eco-Paleo, F-59000, Lille, France.
| | - Beatriz G Waisfeld
- Universidad Nacional de Córdoba, Facultad de Ciencias Exactas Físicas y Naturales, Córdoba, Argentina.
- CICTERRA (Centro de Investigaciones en Ciencias de la Tierra), CONICET, Córdoba, Argentina.
| |
Collapse
|
6
|
Torgersen KT, Bouton BJ, Hebert AR, Kleyla NJ, Plasencia X, Rolfe GL, Tagliacollo VA, Albert JS. Phylogenetic structure of body shape in a diverse inland ichthyofauna. Sci Rep 2023; 13:20758. [PMID: 38007528 PMCID: PMC10676429 DOI: 10.1038/s41598-023-48086-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Accepted: 11/22/2023] [Indexed: 11/27/2023] Open
Abstract
Body shape is a fundamental metric of animal diversity affecting critical behavioral and ecological dynamics and conservation status, yet previously available methods capture only a fraction of total body-shape variance. Here we use structure-from-motion (SFM) 3D photogrammetry to generate digital 3D models of adult fishes from the Lower Mississippi Basin, one of the most diverse temperate-zone freshwater faunas on Earth, and 3D geometric morphometrics to capture morphologically distinct shape variables, interpreting principal components as growth fields. The mean body shape in this fauna resembles plesiomorphic teleost fishes, and the major dimensions of body-shape disparity are similar to those of other fish faunas worldwide. Major patterns of body-shape disparity are structured by phylogeny, with nested clades occupying distinct portions of the morphospace, most of the morphospace occupied by multiple distinct clades, and one clade (Acanthomorpha) accounting for over half of the total body shape variance. In contrast to previous studies, variance in body depth (59.4%) structures overall body-shape disparity more than does length (31.1%), while width accounts for a non-trivial (9.5%) amount of the total body-shape disparity.
Collapse
Affiliation(s)
| | | | - Alyx R Hebert
- Department of Biology, University of Louisiana, Lafayette, USA
| | - Noah J Kleyla
- Department of Biology, University of Louisiana, Lafayette, USA
| | | | - Garrett L Rolfe
- Department of Biology, University of Louisiana, Lafayette, USA
| | | | - James S Albert
- Department of Biology, University of Louisiana, Lafayette, USA
| |
Collapse
|
7
|
McShea DW. Evolutionary trends and goal directedness. SYNTHESE 2023; 201:178. [PMID: 37192961 PMCID: PMC10166038 DOI: 10.1007/s11229-023-04164-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2022] [Accepted: 04/17/2023] [Indexed: 05/18/2023]
Abstract
The conventional wisdom declares that evolution is not goal directed, that teleological considerations play no part in our understanding of evolutionary trends. Here I argue that, to the contrary, under a current view of teleology, field theory, most evolutionary trends would have to be considered goal directed to some degree. Further, this view is consistent with a modern scientific outlook, and more particularly with evolutionary theory today. Field theory argues that goal directedness is produced by higher-level fields that direct entities contained within them to behave persistently and plastically, that is, returning them to a goal-directed trajectory following perturbations (persistence) and directing them to a goal-directed trajectory from a large range of alternative starting points (plasticity). The behavior of a bacterium climbing a chemical food gradient is persistent and plastic, with guidance provided by the external "food field," the chemical gradient. Likewise, an evolutionary trend that is produced by natural selection is a lineage behaving persistently and plastically under the direction of its local ecology, an "ecological field." Trends directed by selection-generated boundaries, thermodynamic gradients, and certain internal constraints, would also count as goal directed. In other words, most of the causes of evolutionary trends that have been proposed imply goal directedness. However, under field theory, not all trends are goal directed. Examples are discussed. Importantly, nothing in this view suggests that evolution is guided by intentionality, at least none at the level of animal intentionality. Finally, possible implications for our thinking about evolutionary directionality in the history of life are discussed.
Collapse
Affiliation(s)
- Daniel W. McShea
- Biology Department, Duke University, Box 90338, Durham, NC 27708 USA
| |
Collapse
|
8
|
Random and Natural Non-Coding RNA Have Similar Structural Motif Patterns but Differ in Bulge, Loop, and Bond Counts. Life (Basel) 2023; 13:life13030708. [PMID: 36983865 PMCID: PMC10054693 DOI: 10.3390/life13030708] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 02/15/2023] [Accepted: 02/27/2023] [Indexed: 03/08/2023] Open
Abstract
An important question in evolutionary biology is whether (and in what ways) genotype–phenotype (GP) map biases can influence evolutionary trajectories. Untangling the relative roles of natural selection and biases (and other factors) in shaping phenotypes can be difficult. Because the RNA secondary structure (SS) can be analyzed in detail mathematically and computationally, is biologically relevant, and a wealth of bioinformatic data are available, it offers a good model system for studying the role of bias. For quite short RNA (length L≤126), it has recently been shown that natural and random RNA types are structurally very similar, suggesting that bias strongly constrains evolutionary dynamics. Here, we extend these results with emphasis on much larger RNA with lengths up to 3000 nucleotides. By examining both abstract shapes and structural motif frequencies (i.e., the number of helices, bonds, bulges, junctions, and loops), we find that large natural and random structures are also very similar, especially when contrasted to typical structures sampled from the spaces of all possible RNA structures. Our motif frequency study yields another result, where the frequencies of different motifs can be used in machine learning algorithms to classify random and natural RNA with high accuracy, especially for longer RNA (e.g., ROC AUC 0.86 for L = 1000). The most important motifs for classification are the number of bulges, loops, and bonds. This finding may be useful in using SS to detect candidates for functional RNA within ‘junk’ DNA regions.
Collapse
|
9
|
Collins KS, Edie SM, Jablonski D. Convergence and contingency in the evolution of a specialized mode of life: multiple origins and high disparity of rock-boring bivalves. Proc Biol Sci 2023; 290:20221907. [PMID: 36750185 PMCID: PMC9904949 DOI: 10.1098/rspb.2022.1907] [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: 09/22/2022] [Accepted: 01/13/2023] [Indexed: 02/09/2023] Open
Abstract
Evolutionary adaptation to novel, specialized modes of life is often associated with a close mapping of form to the new function, resulting in narrow morphological disparity. For bivalve molluscs, endolithy (rock-boring) has biomechanical requirements thought to diverge strongly from those of ancestral functions. However, endolithy in bivalves has originated at least eight times. Three-dimensional morphometric data representing 75 species from approximately 94% of extant endolithic genera and families, along with 310 non-endolithic species in those families, show that endolithy is evolutionarily accessible from many different morphological starting points. Although some endoliths appear to converge on certain shell morphologies, the range of endolith shell form is as broad as that belonging to any other bivalve substrate use. Nevertheless, endolithy is a taxon-poor function in Bivalvia today. This limited richness does not derive from origination within source clades having significantly low origination or high extinction rates, and today's endoliths are not confined to low-diversity biogeographic regions. Instead, endolithy may be limited by habitat availability. Both determinism (as reflected by convergence among distantly related taxa) and contingency (as reflected by the endoliths that remain close to the disparate morphologies of their source clades) underlie the occupation of endolith morphospace.
Collapse
Affiliation(s)
| | - Stewart M. Edie
- Department of Paleobiology, National Museum of Natural History, Smithsonian Institution, Washington, DC 20013, USA
| | - David Jablonski
- Department of the Geophysical Sciences, University of Chicago, Chicago, IL 60637, USA
| |
Collapse
|
10
|
Tyler J, Younger JL. Diving into a dead-end: asymmetric evolution of diving drives diversity and disparity shifts in waterbirds. Proc Biol Sci 2022; 289:20222056. [PMID: 36515120 PMCID: PMC9748772 DOI: 10.1098/rspb.2022.2056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Diving is a relatively uncommon and highly specialized foraging strategy in birds, mostly observed within the Aequorlitornithes (waterbirds) by groups such as penguins, cormorants and alcids. Three key diving techniques are employed within waterbirds: wing-propelled pursuit diving (e.g. penguins), foot-propelled pursuit diving (e.g. cormorants) and plunge diving (e.g. gannets). How many times diving evolved within waterbirds, whether plunge diving is an intermediate state between aerial foraging and submarine diving, and whether the transition to a diving niche is reversible are not known. Here, we elucidate the evolutionary history of diving in waterbirds. We show that diving has been acquired independently at least 14 times within waterbirds, and this acquisition is apparently irreversible, in a striking example of asymmetric evolution. All three modes of diving have evolved independently, with no evidence for plunge diving as an intermediate evolutionary state. Net diversification rates differ significantly between diving versus non-diving lineages, with some diving clades apparently prone to extinction. We find that body mass is evolving under multiple macroevolutionary regimes, with unique optima for each diving type with varying degrees of constraint. Our findings highlight the vulnerability of highly specialized lineages during the ongoing sixth mass extinction.
Collapse
Affiliation(s)
- Joshua Tyler
- Milner Centre for Evolution, Department of Life Sciences, University of Bath, Claverton Down, Bath BA2 7AY, UK
| | - Jane L. Younger
- Milner Centre for Evolution, Department of Life Sciences, University of Bath, Claverton Down, Bath BA2 7AY, UK,Institute for Marine and Antarctic Studies, University of Tasmania, Battery Point, Hobart, Tasmania 7004, Australia
| |
Collapse
|
11
|
The Predictable Complexity of Evolutionary Allometry. Evol Biol 2022. [DOI: 10.1007/s11692-022-09581-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
|
12
|
Souquet L, Guenser P, Girard C, Mazza M, Rigo M, Goudemand N. Temperature-driven heterochrony as a main evolutionary response to climate changes in conodonts. Proc Biol Sci 2022; 289:20220614. [PMID: 36259210 PMCID: PMC9579755 DOI: 10.1098/rspb.2022.0614] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 09/27/2022] [Indexed: 01/17/2023] Open
Abstract
Can we predict the evolutionary response of organisms to climate changes? The direction of greatest intraspecific phenotypic variance is thought to correspond to an 'evolutionary line of least resistance', i.e. a taxon's phenotype is expected to evolve along that general direction, if not constrained otherwise. In particular, heterochrony, whereby the timing or rate of developmental processes are modified, has often been invoked to describe evolutionary trajectories and it may be advantageous to organisms when rapid adaptation is critical. Yet, to date, little is known empirically as to which covariation patterns, whether static allometry, as measured in adult forms only, or ontogenetic allometry, the basis for heterochrony, may be prevalent in what circumstances. Here, we quantify the morphology of segminiplanate conodont elements during two distinct time intervals separated by more than 130 Myr: the Devonian-Carboniferous boundary and the Carnian-Norian boundary (Late Triassic). We evidence that the corresponding species share similar patterns of intraspecific static allometry. Yet, during both crises, conodont evolution was decoupled from this common evolutionary line of least resistance. Instead, it followed heterochrony-like trajectories that furthermore appear as driven by ocean temperature. This may have implications for our interpretation of conodonts' and past marine ecosystems' response to environmental perturbations.
Collapse
Affiliation(s)
- Louise Souquet
- Ecole Normale Supérieure de Lyon, IGFL, CNRS UMR 5242, UCBL, 46 Allée d'Italie, F-69364 Lyon Cedex 07, France
| | - Pauline Guenser
- Ecole Normale Supérieure de Lyon, IGFL, CNRS UMR 5242, UCBL, 46 Allée d'Italie, F-69364 Lyon Cedex 07, France
- Univ. Lyon, Université Claude Bernard Lyon 1, LEHNA, CNRS UMR 5023, 3-6 rue Raphaël Dubois – Bâtiments Forel, 69622 Villeurbanne Cedex 43
| | | | | | - Manuel Rigo
- Department of Geosciences, University of Padova, Via G. Gradenigo 6, 35131 Padova, Italy
| | - Nicolas Goudemand
- Ecole Normale Supérieure de Lyon, IGFL, CNRS UMR 5242, UCBL, 46 Allée d'Italie, F-69364 Lyon Cedex 07, France
| |
Collapse
|
13
|
Abstract
AbstractEvolvability is best addressed from a multi-level, macroevolutionary perspective through a comparative approach that tests for among-clade differences in phenotypic diversification in response to an opportunity, such as encountered after a mass extinction, entering a new adaptive zone, or entering a new geographic area. Analyzing the dynamics of clades under similar environmental conditions can (partially) factor out shared external drivers to recognize intrinsic differences in evolvability, aiming for a macroevolutionary analog of a common-garden experiment. Analyses will be most powerful when integrating neontological and paleontological data: determining differences among extant populations that can be hypothesized to generate large-scale, long-term contrasts in evolvability among clades; or observing large-scale differences among clade histories that can by hypothesized to reflect contrasts in genetics and development observed directly in extant populations. However, many comparative analyses can be informative on their own, as explored in this overview. Differences in clade-level evolvability can be visualized in diversity-disparity plots, which can quantify positive and negative departures of phenotypic productivity from stochastic expectations scaled to taxonomic diversification. Factors that evidently can promote evolvability include modularity—when selection aligns with modular structure or with morphological integration patterns; pronounced ontogenetic changes in morphology, as in allometry or multiphase life cycles; genome size; and a variety of evolutionary novelties, which can also be evaluated using macroevolutionary lags between the acquisition of a trait and phenotypic diversification, and dead-clade-walking patterns that may signal a loss of evolvability when extrinsic factors can be excluded. High speciation rates may indirectly foster phenotypic evolvability, and vice versa. Mechanisms are controversial, but clade evolvability may be higher in the Cambrian, and possibly early in the history of clades at other times; in the tropics; and, for marine organisms, in shallow-water disturbed habitats.
Collapse
|
14
|
Edie SM, Collins KS, Jablonski D. Specimen alignment with limited point-based homology: 3D morphometrics of disparate bivalve shells (Mollusca: Bivalvia). PeerJ 2022; 10:e13617. [PMID: 35769136 PMCID: PMC9235814 DOI: 10.7717/peerj.13617] [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: 03/10/2022] [Accepted: 06/01/2022] [Indexed: 01/17/2023] Open
Abstract
Background Comparative morphology fundamentally relies on the orientation and alignment of specimens. In the era of geometric morphometrics, point-based homologies are commonly deployed to register specimens and their landmarks in a shared coordinate system. However, the number of point-based homologies commonly diminishes with increasing phylogenetic breadth. These situations invite alternative, often conflicting, approaches to alignment. The bivalve shell (Mollusca: Bivalvia) exemplifies a homologous structure with few universally homologous points-only one can be identified across the Class, the shell 'beak'. Here, we develop an axis-based framework, grounded in the homology of shell features, to orient shells for landmark-based, comparative morphology. Methods Using 3D scans of species that span the disparity of shell morphology across the Class, multiple modes of scaling, translation, and rotation were applied to test for differences in shell shape. Point-based homologies were used to define body axes, which were then standardized to facilitate specimen alignment via rotation. Resulting alignments were compared using pairwise distances between specimen shapes as defined by surface semilandmarks. Results Analysis of 45 possible alignment schemes finds general conformity among the shape differences of 'typical' equilateral shells, but the shape differences among atypical shells can change considerably, particularly those with distinctive modes of growth. Each alignment corresponds to a hypothesis about the ecological, developmental, or evolutionary basis of morphological differences, but we suggest orientation via the hinge line for many analyses of shell shape across the Class, a formalization of the most common approach to morphometrics of shell form. This axis-based approach to aligning specimens facilitates the comparison of approximately continuous differences in shape among phylogenetically broad and morphologically disparate samples, not only within bivalves but across many other clades.
Collapse
Affiliation(s)
- Stewart M. Edie
- Department of Paleobiology, National Museum of Natural History, Smithsonian Institution, Washington, DC, United States
| | - Katie S. Collins
- Department of Earth Sciences, Invertebrates and Plants Palaeobiology Division, Natural History Museum, London, United Kingdom
| | - David Jablonski
- Department of the Geophysical Sciences, University of Chicago, Chicago, IL, United States,Committee on Evolutionary Biology, University of Chicago, Chicago, IL, United States
| |
Collapse
|
15
|
Edie SM, Khouja SC, Collins KS, Crouch NMA, Jablonski D. Evolutionary modularity, integration and disparity in an accretionary skeleton: analysis of venerid Bivalvia. Proc Biol Sci 2022; 289:20211199. [PMID: 35042422 PMCID: PMC8767195 DOI: 10.1098/rspb.2021.1199] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Modular evolution, the relatively independent evolution of body parts, may promote high morphological disparity in a clade. Conversely, integrated evolution via stronger covariation of parts may limit disparity. However, integration can also promote high disparity by channelling morphological evolution along lines of least resistance-a process that may be particularly important in the accumulation of disparity in the many invertebrate systems having accretionary growth. We use a time-calibrated phylogenetic hypothesis and high-density, three-dimensional semilandmarking to analyse the relationship between modularity, integration and disparity in the most diverse extant bivalve family: the Veneridae. In general, venerids have a simple, two-module parcellation of their body that is divided into features of the calcium carbonate shell and features of the internal soft anatomy. This division falls more along developmental than functional lines when placed in the context of bivalve anatomy and biomechanics. The venerid body is tightly integrated in absolute terms, but disparity appears to increase with modularity strength among subclades and ecologies. Thus, shifts towards more mosaic evolution beget higher morphological variance in this speciose family.
Collapse
Affiliation(s)
- Stewart M. Edie
- Department of Paleobiology, National Museum of Natural History, Smithsonian Institution, Washington, DC 20013, USA
| | - Safia C. Khouja
- Department of the Geophysical Sciences, University of Chicago, 5734 South Ellis Ave, Chicago, IL 60637, USA
| | - Katie S. Collins
- Department of Earth Sciences, Invertebrates and Plants Palaeobiology Division, Natural History Museum, London SW7 5BD, UK
| | - Nicholas M. A. Crouch
- Department of the Geophysical Sciences, University of Chicago, 5734 South Ellis Ave, Chicago, IL 60637, USA
| | - David Jablonski
- Department of the Geophysical Sciences, University of Chicago, 5734 South Ellis Ave, Chicago, IL 60637, USA,Committee on Evolutionary Biology, University of Chicago, Chicago, IL 60637, USA
| |
Collapse
|
16
|
Leichty AR, Sinha NR. A Grand Challenge in Development and Evodevo: Quantifying the Role of Development in Evolution. FRONTIERS IN PLANT SCIENCE 2022; 12:752344. [PMID: 35087543 PMCID: PMC8788915 DOI: 10.3389/fpls.2021.752344] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Accepted: 12/07/2021] [Indexed: 06/14/2023]
|
17
|
Dingle K, Ghaddar F, Šulc P, Louis AA. Phenotype Bias Determines How Natural RNA Structures Occupy the Morphospace of All Possible Shapes. Mol Biol Evol 2022; 39:msab280. [PMID: 34542628 PMCID: PMC8763027 DOI: 10.1093/molbev/msab280] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Morphospaces-representations of phenotypic characteristics-are often populated unevenly, leaving large parts unoccupied. Such patterns are typically ascribed to contingency, or else to natural selection disfavoring certain parts of the morphospace. The extent to which developmental bias, the tendency of certain phenotypes to preferentially appear as potential variation, also explains these patterns is hotly debated. Here we demonstrate quantitatively that developmental bias is the primary explanation for the occupation of the morphospace of RNA secondary structure (SS) shapes. Upon random mutations, some RNA SS shapes (the frequent ones) are much more likely to appear than others. By using the RNAshapes method to define coarse-grained SS classes, we can directly compare the frequencies that noncoding RNA SS shapes appear in the RNAcentral database to frequencies obtained upon a random sampling of sequences. We show that: 1) only the most frequent structures appear in nature; the vast majority of possible structures in the morphospace have not yet been explored; 2) remarkably small numbers of random sequences are needed to produce all the RNA SS shapes found in nature so far; and 3) perhaps most surprisingly, the natural frequencies are accurately predicted, over several orders of magnitude in variation, by the likelihood that structures appear upon a uniform random sampling of sequences. The ultimate cause of these patterns is not natural selection, but rather a strong phenotype bias in the RNA genotype-phenotype map, a type of developmental bias or "findability constraint," which limits evolutionary dynamics to a hugely reduced subset of structures that are easy to "find."
Collapse
Affiliation(s)
- Kamaludin Dingle
- Centre for Applied Mathematics and Bioinformatics, Department of Mathematics and Natural Sciences, Gulf University for Science and Technology, Hawally, Kuwait
| | - Fatme Ghaddar
- Centre for Applied Mathematics and Bioinformatics, Department of Mathematics and Natural Sciences, Gulf University for Science and Technology, Hawally, Kuwait
| | - Petr Šulc
- School of Molecular Sciences and Center for Molecular Design and Biomimetics at the Biodesign Institute, Arizona State University, Tempe, AZ, USA
| | - Ard A Louis
- Rudolf Peierls Centre for Theoretical Physics, University of Oxford, Oxford, United Kingdom
| |
Collapse
|
18
|
Feeding ecology has shaped the evolution of modern sharks. Curr Biol 2021; 31:5138-5148.e4. [PMID: 34614390 DOI: 10.1016/j.cub.2021.09.028] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 06/05/2021] [Accepted: 09/09/2021] [Indexed: 11/20/2022]
Abstract
Sharks are iconic predators in today's oceans, yet their modern diversity has ancient origins. In particular, present hypotheses suggest that a combination of mass extinction, global climate change, and competition has regulated the community structure of dominant mackerel (Lamniformes) and ground (Carcharhiniformes) sharks over the last 66 million years. However, while these scenarios advocate an interplay of major abiotic and biotic events, the precise drivers remain obscure. Here, we focus on the role of feeding ecology using a geometric morphometric analysis of 3,837 fossil and extant shark teeth. Our results reveal that morphological segregation rather than competition has characterized lamniform and carcharhiniform evolution. Moreover, although lamniforms suffered a long-term disparity decline potentially linked to dietary "specialization," their recent disparity rivals that of "generalist" carcharhiniforms. We further confirm that low eustatic sea levels impacted lamniform disparity across the end-Cretaceous mass extinction. Adaptations to changing prey availability and the proliferation of coral reef habitats during the Paleogene also likely facilitated carcharhiniform dispersals and cladogenesis, underpinning their current taxonomic dominance. Ultimately, we posit that trophic partitioning and resource utilization shaped past shark ecology and represent critical determinants for their future species survivorship.
Collapse
|
19
|
Evans AR, Pollock TI, Cleuren SGC, Parker WMG, Richards HL, Garland KLS, Fitzgerald EMG, Wilson TE, Hocking DP, Adams JW. A universal power law for modelling the growth and form of teeth, claws, horns, thorns, beaks, and shells. BMC Biol 2021; 19:58. [PMID: 33781258 PMCID: PMC8008625 DOI: 10.1186/s12915-021-00990-w] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Accepted: 02/22/2021] [Indexed: 11/29/2022] Open
Abstract
Background A major goal of evolutionary developmental biology is to discover general models and mechanisms that create the phenotypes of organisms. However, universal models of such fundamental growth and form are rare, presumably due to the limited number of physical laws and biological processes that influence growth. One such model is the logarithmic spiral, which has been purported to explain the growth of biological structures such as teeth, claws, horns, and beaks. However, the logarithmic spiral only describes the path of the structure through space, and cannot generate these shapes. Results Here we show a new universal model based on a power law between the radius of the structure and its length, which generates a shape called a ‘power cone’. We describe the underlying ‘power cascade’ model that explains the extreme diversity of tooth shapes in vertebrates, including humans, mammoths, sabre-toothed cats, tyrannosaurs and giant megalodon sharks. This model can be used to predict the age of mammals with ever-growing teeth, including elephants and rodents. We view this as the third general model of tooth development, along with the patterning cascade model for cusp number and spacing, and the inhibitory cascade model that predicts relative tooth size. Beyond the dentition, this new model also describes the growth of claws, horns, antlers and beaks of vertebrates, as well as the fangs and shells of invertebrates, and thorns and prickles of plants. Conclusions The power cone is generated when the radial power growth rate is unequal to the length power growth rate. The power cascade model operates independently of the logarithmic spiral and is present throughout diverse biological systems. The power cascade provides a mechanistic basis for the generation of these pointed structures across the tree of life. Supplementary Information The online version contains supplementary material available at 10.1186/s12915-021-00990-w.
Collapse
Affiliation(s)
- Alistair R Evans
- School of Biological Sciences, Monash University, Melbourne, Victoria, 3800, Australia. .,Geosciences, Museums Victoria, Melbourne, Victoria, 3001, Australia.
| | - Tahlia I Pollock
- School of Biological Sciences, Monash University, Melbourne, Victoria, 3800, Australia
| | - Silke G C Cleuren
- School of Biological Sciences, Monash University, Melbourne, Victoria, 3800, Australia
| | - William M G Parker
- School of Biological Sciences, Monash University, Melbourne, Victoria, 3800, Australia
| | - Hazel L Richards
- School of Biological Sciences, Monash University, Melbourne, Victoria, 3800, Australia
| | - Kathleen L S Garland
- School of Biological Sciences, Monash University, Melbourne, Victoria, 3800, Australia
| | - Erich M G Fitzgerald
- School of Biological Sciences, Monash University, Melbourne, Victoria, 3800, Australia.,Geosciences, Museums Victoria, Melbourne, Victoria, 3001, Australia
| | - Tim E Wilson
- School of Mathematical Sciences, Monash University, Melbourne, Victoria, 3800, Australia
| | - David P Hocking
- School of Biological Sciences, Monash University, Melbourne, Victoria, 3800, Australia.,Geosciences, Museums Victoria, Melbourne, Victoria, 3001, Australia
| | - Justin W Adams
- Biomedicine Discovery Institute, Monash University, Melbourne, Victoria, 3800, Australia
| |
Collapse
|
20
|
Martins BO, Franco-Belussi L, Siqueira MS, Fernandes CE, Provete DB. The evolution of red blood cell shape in fishes. J Evol Biol 2021; 34:537-548. [PMID: 33484056 DOI: 10.1111/jeb.13757] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2020] [Revised: 12/17/2020] [Accepted: 12/18/2020] [Indexed: 12/18/2022]
Abstract
The size and shape of red blood cells (RBCs) provide key information on life-history strategies in vertebrates. However, little is known about how RBC shape evolved in response to environmental factors, body size and the role of evolutionary rate. Here, we analysed RBC morphometrics in a set of Teleostei (bony fishes) and Elasmobranchii (sharks and rays) species testing the hypothesis that phylogenetic relationship explains species occupation of morphospace. We collected data on cell and nucleus area and volume, nucleus:cytoplasm ratio and shape factor for 65 species belonging to 28 orders. Then, we built phylomorphospaces separately for bony fish and sharks and rays. To test whether phylogenetic relationships predicted phenotypic similarity, we calculated multivariate phylogenetic signal. We also estimated the evolutionary rate of RBC shape for each node and tip using ridge regression. Finally, we tested whether habitat and body size influenced RBC shape using a PGLS. We found a significant phylogenetic signal in RBC shape for bony fish, but not sharks and rays. Saltwater teleost species were more clustered than freshwater ones in the phylomorphospace, suggesting clade disparity. Accordingly, the rate of evolution was highly heterogeneous, with significant decrease in Acanthopterygii. Neither habitat nor body size influenced RBC shape. In conclusion, RBC shape seems to have evolved in fishes in response to multiple selective pressures independent of life-history characters.
Collapse
Affiliation(s)
- Brenda Oliveira Martins
- Graduate Program in Animal Biology, Instituto de Biociências, Universidade Federal de Mato Grosso do Sul, Campo Grande, Brasil
| | - Lilian Franco-Belussi
- Instituto de Biociências, Universidade Federal de Mato Grosso do Sul, Campo Grande, Brasil
| | | | - Carlos E Fernandes
- Instituto de Biociências, Universidade Federal de Mato Grosso do Sul, Campo Grande, Brasil
| | - Diogo B Provete
- Instituto de Biociências, Universidade Federal de Mato Grosso do Sul, Campo Grande, Brasil.,Gothenburg Global Biodiversity Centre, Göteborg, Sweden
| |
Collapse
|
21
|
A release from developmental bias accelerates morphological diversification in butterfly eyespots. Proc Natl Acad Sci U S A 2020; 117:27474-27480. [PMID: 33093195 DOI: 10.1073/pnas.2008253117] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Development can bias the independent evolution of traits sharing ontogenetic pathways, making certain evolutionary changes less likely. The eyespots commonly found on butterfly wings each have concentric rings of differing colors, and these serially repeated pattern elements have been a focus for evo-devo research. In the butterfly family Nymphalidae, eyespots have been shown to function in startling or deflecting predators and to be involved in sexual selection. Previous work on a model species of Mycalesina butterfly, Bicyclus anynana, has provided insights into the developmental control of the size and color composition of individual eyespots. Experimental evolution has also shown that the relative size of a pair of eyespots on the same wing surface is highly flexible, whereas they are resistant to diverging in color composition, presumably due to the underlying shared developmental process. This fixed color composition has been considered as a prime example of developmental bias with significant consequences for wing pattern evolution. Here, we test this proposal by surveying eyespots across the whole subtribe of Mycalesina butterflies and demonstrate that developmental bias shapes evolutionary diversification except in the genus Heteropsis which has gained independent control of eyespot color composition. Experimental manipulations of pupal wings reveal that the bias has been released through a novel regional response of the wing tissue to a conserved patterning signal. Our study demonstrates that development can bias the evolutionary independence of traits, but it also shows how bias can be released through developmental innovations, thus, allowing rapid morphological change, facilitating evolutionary diversification.
Collapse
|
22
|
Machado FA. Selection and Constraints in the Ecomorphological Adaptive Evolution of the Skull of Living Canidae (Carnivora, Mammalia). Am Nat 2020; 196:197-215. [PMID: 32673094 DOI: 10.1086/709610] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The association between phenotype and ecology is essential for understanding the environmental drivers of morphological evolution. This is a particularly challenging task when dealing with complex traits, such as the skull, where multiple selective pressures are at play and evolution might be constrained by ontogenetic and genetic factors. I integrate morphometric tools, comparative methods, and quantitative genetics to investigate how ontogenetic constraints and selection might have interacted during the evolution of the skull in extant Canidae. The results confirm that the evolution of cranial morphology was largely adaptive and molded by changes in diet composition. While the investigation of the adaptive landscape reveals two main selective lines of least resistance (one associated with size and one associated with functional shape features), rates of evolution along size were higher than those found for shape dimensions, suggesting the influence of constraints on morphological evolution. Structural modeling analyses revealed that size, which is the line of most genetic/phenotypic variation, might have acted as a constraint, negatively impacting dietary evolution. Constraints might have been overcome in the case of selection for the consumption of large prey by associating strong selection along both size and shape directions. The results obtained here show that microevolutionary constraints may have played a role in shaping macroevolutionary patterns of morphological evolution.
Collapse
|
23
|
Affiliation(s)
- Armin P Moczek
- Department of Biology, Indiana University, Bloomington, Indiana
| |
Collapse
|