scholarly journals Correcting for Body Size Variation in Morphometric Analysis

2021 ◽  
Author(s):  
Kin Onn Chan ◽  
Lee Grismer
Keyword(s):  
Body Size ◽  
Size Variation ◽  
R Package ◽  
Analysis Of Covariance ◽  
Relative Efficacy ◽  
Allometric Growth ◽  
Body Size Variation ◽  
Components Analysis ◽  
Size Correction ◽  
Negative Impacts

Using an allometric growth model to correct for body size variation has been known for many decades to be superior to several other widely used methods such as ratios, analysis of covariance, principal components analysis, and residual analysis. However, this technique remains relatively obscure and rarely applied. We optimize the implementation of this method through a newly developed and easy-to-use R package GroupStruct and use empirical datasets to test its relative efficacy compared to several commonly used methods. Our results demonstrate the superiority of the allometric method and highlights the negative impacts of applying improper body size correction methods.

scholarly journals Mammalian body size is determined by interactions between climate, urbanization, and ecological traits

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Maggie M. Hantak ◽  
Bryan S. McLean ◽  
Daijiang Li ◽  
Robert P. Guralnick
Keyword(s):  
Body Size ◽  
Resource Availability ◽  
Critical Role ◽  
Size Variation ◽  
Ecological Factors ◽  
Species Traits ◽  
Body Size Variation ◽  
Resource Availability Hypothesis ◽  
Urban Heat ◽  
Thermal Buffering

AbstractAnthropogenically-driven climate warming is a hypothesized driver of animal body size reductions. Less understood are effects of other human-caused disturbances on body size, such as urbanization. We compiled 140,499 body size records of over 100 North American mammals to test how climate and human population density, a proxy for urbanization, and their interactions with species traits, impact body size. We tested three hypotheses of body size variation across urbanization gradients: urban heat island effects, habitat fragmentation, and resource availability. Our results demonstrate that both urbanization and temperature influence mammalian body size variation, most often leading to larger individuals, thus supporting the resource availability hypothesis. In addition, life history and other ecological factors play a critical role in mediating the effects of climate and urbanization on body size. Larger mammals and species that utilize thermal buffering are more sensitive to warmer temperatures, while flexibility in activity time appears to be advantageous in urbanized areas. This work highlights the value of using digitized, natural history data to track how human disturbance drives morphological variation.

scholarly journals The role of local versus biogeographical processes in influencing diversity and body‐size variation in mammal assemblages

2016 ◽  
Vol 6 (5) ◽  
pp. 1447-1456 ◽  
Author(s):  
Luiz Carlos S. Lopez ◽  
Marcos S. L. Figueiredo ◽  
Maria Paula de Aguiar Fracasso ◽  
Daniel Oliveira Mesquita ◽  
Ulisses Umbelino Anjos ◽  
...  
Keyword(s):  
Body Size ◽  
Size Variation ◽  
Body Size Variation ◽  
Mammal Assemblages

scholarly journals Insights into body size variation in cetaceans from the evolution of body-size-related genes

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Yingying Sun ◽  
Yanzhi Liu ◽  
Xiaohui Sun ◽  
Yurui Lin ◽  
Daiqing Yin ◽  
...  
Keyword(s):  
Body Size ◽  
Size Variation ◽  
Body Size Variation

Geographic variation in body size of American mink ( Mustela vison ) / Variation géographique de la taille du corps chez le vison d'Amérique ( Mustela vison )

Mammalia ◽  
2006 ◽  
Vol 70 (1-2) ◽  
Author(s):  
Richard T. Stevens ◽  
Michael L. Kennedy
Keyword(s):  
Body Size ◽  
American Mink ◽  
Size Variation ◽  
Mustela Vison ◽  
Morphological Characters ◽  
Geographic Proximity ◽  
Multivariate Statistical ◽  
Components Analysis ◽  
Individual Variables ◽  
Variation Géographique

AbstractSpatial variation in 26 morphological characters of American mink ( Mustela vison ) from 35 localities in North America was investigated using univariate and multivariate statistical analyses. Localities were chosen based on watersheds, and it was hypothesized that high levels of gene flow in minks would prevent partitioning of body size variation within watersheds. All 26 characters in males and 25 of 26 in females exhibited significant interlocality variation. The patterns of variation in body size resulting from principal components analysis indicated that, for both sexes, minks were largest in Alaska, Manitoba, and Alberta; smallest minks were found in Florida and Quebec. There did not appear to be a relationship between body size and geographic proximity. Environmental factors collectively were found to be related to body size, although individual variables were not typically significant. Of 16 environmental variables examined, only longitude was correlated with body size in both sexes, with largest minks in the west and smallest in the east. Latitude was also correlated with body size in females. It was concluded that variation in body size of mink was likely the result of more than one factor that includes both biotic and abiotic features.

Geographic variation in body size and sexual size dimorphism of North American Ratsnakes (Pantherophis spp. s.l.)

2018 ◽  
Vol 96 (11) ◽  
pp. 1196-1202 ◽  
Author(s):  
Brett A. DeGregorio ◽  
Gabriel Blouin-Demers ◽  
Gerardo L.F. Carfagno ◽  
J. Whitfield Gibbons ◽  
Stephen J. Mullin ◽  
...  
Keyword(s):  
Body Size ◽  
Large Scale ◽  
Sexual Size Dimorphism ◽  
Size Variation ◽  
Sexually Dimorphic ◽  
Male Body ◽  
Complex Species ◽  
Size Dimorphism ◽  
Body Size Variation ◽  
Female Body Size

Because body size affects nearly all facets of an organism’s life history, ecologists have long been interested in large-scale patterns of body-size variation, as well as why those large-scale patterns often differ between sexes. We explored body-size variation across the range of the sexually dimorphic Ratsnake complex (species of the genus Pantherophis Fitzinger, 1843 s.l.; formerly Elaphe obsoleta (Say in James, 1823)) in North America. We specifically explored whether variation in body size followed latitudinal patterns or varied with climatic variables. We found that body size did not conform to a climatic or latitudinal gradient, but instead, some of the populations with the largest snakes occurred near the core of the geographic range and some with the smallest occurred near the northern, western, and southern peripheries of the range. Males averaged 14% larger than females, although the degree of sexual size dimorphism varied between populations (range: 2%–25%). There was a weak trend for male body size to change in relation to temperature, whereas female body size did not. Our results indicate that relationships between climate and an ectotherm’s body size are more complicated than linear latitudinal clines and likely differ for males and females.

scholarly journals Temperature‐driven color lightness and body size variation scale to local assemblages of European Odonata but are modified by propensity for dispersal

2020 ◽  
Vol 10 (16) ◽  
pp. 8936-8948
Author(s):  
Daniel Acquah‐Lamptey ◽  
Martin Brändle ◽  
Roland Brandl ◽  
Stefan Pinkert
Keyword(s):  
Body Size ◽  
Size Variation ◽  
Body Size Variation

Effects of latitude and allopatry on body size variation in European water shrews

2008 ◽  
Vol 53 (1) ◽  
pp. 39-46 ◽  
Author(s):  
Boris Kryštufek ◽  
Aila Quadracci
Keyword(s):  
Body Size ◽  
Size Variation ◽  
Body Size Variation ◽  
European Water

scholarly journals New footprints from Laetoli (Tanzania) provide evidence for marked body size variation in early hominins

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Fidelis T Masao ◽  
Elgidius B Ichumbaki ◽  
Marco Cherin ◽  
Angelo Barili ◽  
Giovanni Boschian ◽  
...  
Keyword(s):  
Body Size ◽  
Sexual Dimorphism ◽  
Size Variation ◽  
Single Species ◽  
Australopithecus Afarensis ◽  
Body Size Variation ◽  
Northern Tanzania ◽  
The World ◽  
Marked Body ◽  
Considerable Body

Laetoli is a well-known palaeontological locality in northern Tanzania whose outstanding record includes the earliest hominin footprints in the world (3.66 million years old), discovered in 1978 at Site G and attributed to Australopithecus afarensis. Here, we report hominin tracks unearthed in the new Site S at Laetoli and referred to two bipedal individuals (S1 and S2) moving on the same palaeosurface and in the same direction as the three hominins documented at Site G. The stature estimates for S1 greatly exceed those previously reconstructed for Au. afarensis from both skeletal material and footprint data. In combination with a comparative reappraisal of the Site G footprints, the evidence collected here embodies very important additions to the Pliocene record of hominin behaviour and morphology. Our results are consistent with considerable body size variation and, probably, degree of sexual dimorphism within a single species of bipedal hominins as early as 3.66 million years ago.

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