1
|
Conaway MA, Adams DC. An effect size for comparing the strength of morphological integration across studies. Evolution 2022; 76:2244-2259. [PMID: 35971251 DOI: 10.1111/evo.14595] [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: 01/18/2022] [Accepted: 06/16/2022] [Indexed: 01/22/2023]
Abstract
Understanding how and why phenotypic traits covary is a major interest in evolutionary biology. Biologists have long sought to characterize the extent of morphological integration in organisms, but comparing levels of integration for a set of traits across taxa has been hampered by the lack of a reliable summary measure and testing procedure. Here, we propose a standardized effect size for this purpose, calculated from the relative eigenvalue variance,V r e l $V_{rel}$ . First, we evaluate several eigenvalue dispersion indices under various conditions, and show that onlyV r e l $V_{rel}$ remains stable across samples size and the number of variables. We then demonstrate thatV r e l $V_{rel}$ accurately characterizes input patterns of covariation, so long as redundant dimensions are excluded from the calculations. However, we also show that the variance of the sampling distribution ofV r e l $V_{rel}$ depends on input levels of trait covariation, makingV r e l $V_{rel}$ unsuitable for direct comparisons. As a solution, we propose transformingV r e l $V_{rel}$ to a standardized effect size (Z-score) for representing the magnitude of integration for a set of traits. We also propose a two-sample test for comparing the strength of integration between taxa, and show that this test displays appropriate statistical properties. We provide software for implementing the procedure, and an empirical example illustrates its use.
Collapse
Affiliation(s)
- Mark A Conaway
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, Iowa, USA
| | - Dean C Adams
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, Iowa, USA
| |
Collapse
|
2
|
Watanabe J. Statistics of eigenvalue dispersion indices: Quantifying the magnitude of phenotypic integration. Evolution 2021; 76:4-28. [PMID: 34679186 DOI: 10.1111/evo.14382] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 09/13/2021] [Accepted: 09/20/2021] [Indexed: 01/28/2023]
Abstract
Analysis of trait covariation plays a pivotal role in the study of phenotypic evolution. The magnitude of covariation is often quantified with statistics based on dispersion of eigenvalues of a covariance or correlation matrix-eigenvalue dispersion indices. This study clarifies the statistical justifications of these statistics and elaborates on their sampling properties. The relative eigenvalue variance of a covariance matrix is known in the statistical literature a test statistic for sphericity, and thus is an appropriate measure of eccentricity of variation. The same of a correlation matrix is equal to the average squared correlation, which has a straightforward interpretation as a measure of integration. Here, expressions for the mean and variance of these statistics are analytically derived under multivariate normality, clarifying the effects of sample size N, number of variables p, and parameters on sampling bias and error. Simulations confirm that approximations involved are reasonably accurate with a moderate sample size (N ≥ 16-64). Importantly, sampling properties of these indices are not adversely affected by a high p:N ratio, promising their utility in high-dimensional phenotypic analyses. They can furthermore be applied to shape variables and phylogenetically structured data with appropriate modifications.
Collapse
Affiliation(s)
- Junya Watanabe
- Department of Earth Sciences, University of Cambridge, Cambridge, United Kingdom
| |
Collapse
|
3
|
Arlegi M, Veschambre‐Couture C, Gómez‐Olivencia A. Evolutionary selection and morphological integration in the vertebral column of modern humans. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2019; 171:17-36. [DOI: 10.1002/ajpa.23950] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 07/03/2019] [Accepted: 09/26/2019] [Indexed: 01/22/2023]
Affiliation(s)
- Mikel Arlegi
- Departamento de Estratigrafía y Paleontología, Facultad de Ciencia y TecnologíaUniversidad del País Vasco‐Euskal Herriko Unibertsitatea (UPV/EHU) Leioa Spain
- Université de Bordeaux, PACEA UMR 5199 Pessac France
| | | | - Asier Gómez‐Olivencia
- Departamento de Estratigrafía y Paleontología, Facultad de Ciencia y TecnologíaUniversidad del País Vasco‐Euskal Herriko Unibertsitatea (UPV/EHU) Leioa Spain
- IKERBASQUE. Basque Foundation for Science Bizkaia Spain
- Centro UCM‐ISCIII de Investigación sobre Evolución y Comportamiento Humanos Madrid Spain
| |
Collapse
|
4
|
Affiliation(s)
- M. Iijima
- School of Resources and Environmental Engineering Hefei University of Technology Hefei China
| | - T. Kubo
- The University Museum The University of Tokyo Tokyo Japan
| |
Collapse
|
5
|
Abstract
Morphological integration and modularity are important for understanding phenotypic evolution because they constrain variation subjected to selection and enable independent evolution of functional and developmental units. We report dental integration and modularity in representative otariid (Eumetopias jubatus, Callorhinus ursinus) and phocid (Phoca largha, Histriophoca fasciata) species of Pinnipedia. This is the first study of integration and modularity in a secondarily simplified dentition with simple occlusion. Integration was stronger in both otariid species than in either phocid species and related positively to dental occlusion and negatively to both modularity and tooth-size variability across all the species. The canines and third upper incisor were most strongly integrated, comprising a module that likely serves as occlusal guides for the postcanines. There was no or weak modularity among tooth classes. The reported integration is stronger than or similar to that in mammals with complex dentition and refined occlusion. We hypothesise that this strong integration is driven by dental occlusion, and that it is enabled by reduction of modularity that constrains overall integration in complex dentitions. We propose that modularity was reduced in pinnipeds during the transition to aquatic life in association with the origin of pierce-feeding and loss of mastication caused by underwater feeding.
Collapse
|
6
|
Watanabe J. Clade-specific evolutionary diversification along ontogenetic major axes in avian limb skeleton. Evolution 2018; 72:2632-2652. [PMID: 30328113 DOI: 10.1111/evo.13627] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Revised: 10/02/2018] [Accepted: 10/07/2018] [Indexed: 12/16/2022]
Abstract
The evolutionary diversification of birds has been facilitated by specializations for various locomotor modes, with which the proportion of the limb skeleton is closely associated. However, recent studies have identified phylogenetic signals in this system, suggesting the presence of historical factors that have affected its evolutionary variability. In this study, to explore potential roles of ontogenetic integration in biasing the evolution in the avian limb skeleton, evolutionary diversification patterns in six avian families (Anatidae, Procellariidae, Ardeidae, Phalacrocoracidae, Laridae, and Alcidae) were examined and compared to the postnatal ontogenetic trajectories in those taxa, based on measurement of 2641 specimens and recently collected ontogenetic series, supplemented by published data. Morphometric analyses of lengths of six limb bones (humerus, ulna, carpometacarpus, femur, tibiotarsus, and tarsometatarsus) demonstrated that: (1) ontogenetic trajectories are diverse among families; (2) evolutionary diversification is significantly anisotropic; and, most importantly, (3) major axes of evolutionary diversification are correlated with clade-specific ontogenetic major axes in the shape space. These results imply that the evolutionary variability of the avian limbs has been biased along the clade-specific ontogenetic trajectories. It may explain peculiar diversification patterns characteristic to some avian groups, including the long-leggedness in Ardeidae and tendency for flightlessness in Anatidae.
Collapse
Affiliation(s)
- Junya Watanabe
- Department of Geology and Mineralogy, Kyoto University, Kyoto, Japan
| |
Collapse
|
7
|
Nijhout HF, McKenna KZ. The Origin of Novelty Through the Evolution of Scaling Relationships. Integr Comp Biol 2017. [DOI: 10.1093/icb/icx049] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
|
8
|
Green AJ. ALLOMETRY OF GENITALIA IN INSECTS AND SPIDERS: ONE SIZE DOES NOT FIT ALL. Evolution 2017; 53:1621-1624. [DOI: 10.1111/j.1558-5646.1999.tb05427.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/1998] [Accepted: 03/29/1999] [Indexed: 12/01/2022]
Affiliation(s)
- Andy J. Green
- Department of Applied Biology, Estación Biológica de Doñana; CSIC, Avda. María Luisa s/n; 41013 Sevilla Spain
| |
Collapse
|
9
|
Armbruster WS, Pélabon C, Bolstad GH, Hansen TF. Integrated phenotypes: understanding trait covariation in plants and animals. Philos Trans R Soc Lond B Biol Sci 2014; 369:20130245. [PMID: 25002693 PMCID: PMC4084533 DOI: 10.1098/rstb.2013.0245] [Citation(s) in RCA: 169] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Integration and modularity refer to the patterns and processes of trait interaction and independence. Both terms have complex histories with respect to both conceptualization and quantification, resulting in a plethora of integration indices in use. We review briefly the divergent definitions, uses and measures of integration and modularity and make conceptual links to allometry. We also discuss how integration and modularity might evolve. Although integration is generally thought to be generated and maintained by correlational selection, theoretical considerations suggest the relationship is not straightforward. We caution here against uncontrolled comparisons of indices across studies. In the absence of controls for trait number, dimensionality, homology, development and function, it is difficult, or even impossible, to compare integration indices across organisms or traits. We suggest that care be invested in relating measurement to underlying theory or hypotheses, and that summative, theory-free descriptors of integration generally be avoided. The papers that follow in this Theme Issue illustrate the diversity of approaches to studying integration and modularity, highlighting strengths and pitfalls that await researchers investigating integration in plants and animals.
Collapse
Affiliation(s)
- W Scott Armbruster
- School of Biological Sciences, University of Portsmouth, Portsmouth PO12DY, UK Institute of Arctic Biology, University of Alaska, Fairbanks, AK 99775, USA Department of Biology, Norwegian University of Science and Technology, 7491 Trondheim, Norway
| | - Christophe Pélabon
- Center for Biodiversity Dynamics, Department of Biology, Norwegian University of Science and Technology, 7491 Trondheim, Norway
| | - Geir H Bolstad
- Center for Biodiversity Dynamics, Department of Biology, Norwegian University of Science and Technology, 7491 Trondheim, Norway
| | - Thomas F Hansen
- Centre for Ecological and Evolutionary Synthesis, Department of Biology, University of Oslo, PO Box 1066, 0316 Oslo, Norway
| |
Collapse
|
10
|
Klingenberg CP, Marugán-Lobón J. Evolutionary Covariation in Geometric Morphometric Data: Analyzing Integration, Modularity, and Allometry in a Phylogenetic Context. Syst Biol 2013; 62:591-610. [DOI: 10.1093/sysbio/syt025] [Citation(s) in RCA: 267] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Affiliation(s)
- Christian Peter Klingenberg
- Faculty of Life Sciences, University of Manchester, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK; and 2Unidad de Paleontología, Departamento de Biología, C/Darwin 2, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain
| | - Jesús Marugán-Lobón
- Faculty of Life Sciences, University of Manchester, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK; and 2Unidad de Paleontología, Departamento de Biología, C/Darwin 2, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain
| |
Collapse
|
11
|
Baker J, Workman M, Bedrick E, Frey MA, Hurtado M, Pearson O. Brains versus brawn: an empirical test of Barker's brain sparing model. Am J Hum Biol 2010; 22:206-15. [PMID: 19701887 DOI: 10.1002/ajhb.20979] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The Barker model of the in utero origins of diminished muscle mass in those born small invokes the adaptive "sparing" of brain tissue development at the expense of muscle. Though compelling, to date this model has not been directly tested. This article develops an allometric framework for testing the principal prediction of the Barker model-that among those born small muscle mass is sacrificed to spare brain growth-then evaluates this hypothesis using data from the third National Health and Nutrition Examination Survey (NHANES III). The results indicate clear support for a negative relationship between the allometric development of the two tissues; however, a further consideration of conserved mammalian fetal circulatory patterns suggests the possibility that system-constrained patterns of developmental damage and "bet-hedging" responses in affected tissues may provide a more adequate explanation of the results. Far from signaling the end of studies of adaptive developmental programming, this perspective may open a promising new avenue of inquiry within the fields of human biology and the developmental origins of health and disease.
Collapse
Affiliation(s)
- Jack Baker
- Department of Anthropology, Bureau of Business and Economic Research, University of New Mexico, Albuquerque, NM 87131-0001, USA.
| | | | | | | | | | | |
Collapse
|
12
|
Mitteroecker P, Bookstein F. THE ONTOGENETIC TRAJECTORY OF THE PHENOTYPIC COVARIANCE MATRIX, WITH EXAMPLES FROM CRANIOFACIAL SHAPE IN RATS AND HUMANS. Evolution 2009; 63:727-37. [DOI: 10.1111/j.1558-5646.2008.00587.x] [Citation(s) in RCA: 98] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
|
13
|
Maxwell EE, Harrison LB. Ossification sequence of the common tern (Sterna hirundo) and its implications for the interrelationships of the Lari (Aves, Charadriiformes). J Morphol 2008; 269:1056-72. [DOI: 10.1002/jmor.10633] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
14
|
Ontogeny of skull size and shape changes within a framework of biphasic lifestyle: a case study in six Triturus species (Amphibia, Salamandridae). ZOOMORPHOLOGY 2007. [DOI: 10.1007/s00435-007-0037-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|
15
|
KLINGENBERG CHRISTIANPETER. Heterochrony and allometry: the analysis of evolutionary change in ontogeny. Biol Rev Camb Philos Soc 2007. [DOI: 10.1111/j.1469-185x.1997.tb00026.x] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
|
16
|
|
17
|
Badyaev AV, Whittingham LA, Hill GE. THE EVOLUTION OF SEXUAL SIZE DIMORPHISM IN THE HOUSE FINCH. III. DEVELOPMENTAL BASIS. Evolution 2001. [DOI: 10.1554/0014-3820(2001)055[0176:teossd]2.0.co;2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|
18
|
|
19
|
Badyaev AV, Hill GE, Whittingham LA. THE EVOLUTION OF SEXUAL SIZE DIMORPHISM IN THE HOUSE FINCH. IV. POPULATION DIVERGENCE IN ONTOGENY. Evolution 2001. [DOI: 10.1554/0014-3820(2001)055[2534:teossd]2.0.co;2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|
20
|
Badyaev, Martin. Individual variation in growth trajectories: phenotypic and genetic correlations in ontogeny of the house finch (Carpodacus mexicanus). J Evol Biol 2000. [DOI: 10.1046/j.1420-9101.2000.00172.x] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
21
|
Abstract
Within all species of animals, the size of each organ bears a specific relationship to overall body size. These patterns of organ size relative to total body size are called static allometry and have enchanted biologists for centuries, yet the mechanisms generating these patterns have attracted little experimental study. We review recent and older work on holometabolous insect development that sheds light on these mechanisms. In insects, static allometry can be divided into at least two processes: (1) the autonomous specification of organ identity, perhaps including the approximate size of the organ, and (2) the determination of the final size of organs based on total body size. We present three models to explain the second process: (1) all organs autonomously absorb nutrients and grow at organ-specific rates, (2) a centralized system measures a close correlate of total body size and distributes this information to all organs, and (3) autonomous organ growth is combined with feedback between growing organs to modulate final sizes. We provide evidence supporting models 2 and 3 and also suggest that hormones are the messengers of size information. Advances in our understanding of the mechanisms of allometry will come through the integrated study of whole tissues using techniques from development, genetics, endocrinology and population biology.
Collapse
Affiliation(s)
- D L Stern
- Laboratory for Development and Evolution, University Museum of Zoology and Department of Zoology, Downing Street, Cambridge, CB2 3EJ, UK.
| | | |
Collapse
|