87:6535 The significance of body size, dispersal potential, and habitat for rates of morphological evolution in stomatopod Crustacea

1987 ◽  
Vol 34 (11) ◽  
pp. 993
Keyword(s):  
Body Size ◽  
Morphological Evolution ◽  
Dispersal Potential

scholarly journals Genome size drives morphological evolution in organ-specific ways

2021 ◽  
Author(s):  
Michael W Itgen ◽  
Dustin S Siegel ◽  
Stanley K Sessions ◽  
Rachel Lockridge Mueller
Keyword(s):  
Body Size ◽  
Genome Size ◽  
Cell Size ◽  
Structural Changes ◽  
Morphological Evolution ◽  
Empty Space ◽  
Developmental Rate ◽  
Cellular Interactions ◽  
Structure Changes ◽  
Organ Specific

Morphogenesis is an emergent property of biochemical and cellular interactions during development. Genome size and the correlated trait of cell size can influence these interactions through its effects on developmental rate and tissue geometry, ultimately driving the evolution of morphology. We tested the effects of genome size and body size evolution on heart and liver morphology using nine species of the salamander genus Plethodon (genome sizes 29.3-67 Gb). Our results show that whole organ size is determined by body size, whereas tissue structure changes dramatically with evolutionary increases in genome size. In the heart, increased genome size is correlated with a reduction of myocardia in the ventricle, yielding proportionally less force-producing mass and more empty space. In the liver, increased genome size is correlated with fewer and larger vascular structures, positioning hepatocytes farther from the circulatory vessels that transport key metabolites. Although these structural changes should have obvious impacts on organ function, their effects on organismal performance and fitness are likely negligible because low metabolic rates in salamanders relax selective pressure on key metabolic organ performance. Overall, this study reveals the effects of large genome and cell size on the developmental systems producing the heart and liver.

Warning signals promote morphological diversification in fossorial uropeltid snakes (Squamata: Uropeltidae)

2020 ◽  
Author(s):  
Vivek Philip Cyriac ◽  
Ullasa Kodandaramaiah
Keyword(s):  
Body Size ◽  
Free Space ◽  
Morphological Evolution ◽  
Environmental Constraints ◽  
Shape Evolution ◽  
Head Shape ◽  
Warning Signals ◽  
Morphological Diversification ◽  
Niche Expansion ◽  
Antipredator Defences

Abstract Many species possess warning colourations that signal unprofitability to predators. Warning colourations are also thought to provide prey with a ‘predator-free space’ and promote niche expansion. However, how such strategies release a species from environmental constraints and facilitate niche expansion is not clearly understood. Fossoriality in reptiles imposes several morphological limits on head and body size to facilitate burrowing underground, but many fossorial snakes live close to the surface and occasionally move above ground, exposing them to predators. In such cases, evolving antipredator defences that reduce predation on the surface could potentially relax the morphological constraints associated with fossoriality and promote morphological diversification. Fossorial uropeltid snakes possess varying degrees of conspicuous warning colourations that reduce avian predation when active above ground. We predicted that species with more conspicuous colourations will exhibit more robust body forms and show faster rates of morphological evolution because constraints imposed by fossoriality are relaxed. Using a comparative phylogenetic approach on the genus Uropeltis, we show that more conspicuous species tend to have more robust morphologies and have faster rates of head-shape evolution. Overall, we find that the evolution of warning colourations in Uropeltis can facilitate niche expansion by influencing rates of morphological diversification.

scholarly journals Rates of ecological divergence and body size evolution are correlated with species diversification in scaly tree ferns

2016 ◽  
Vol 283 (1834) ◽  
pp. 20161098 ◽  
Author(s):  
Santiago Ramírez-Barahona ◽  
Josué Barrera-Redondo ◽  
Luis E. Eguiarte
Keyword(s):  
Species Richness ◽  
Body Size ◽  
Ecological Niche ◽  
Morphological Evolution ◽  
Ecological Niches ◽  
Species Diversification ◽  
Tree Ferns ◽  
Size Evolution ◽  
Body Sizes ◽  
Body Size Evolution

Variation in species richness across regions and between different groups of organisms is a major feature of evolution. Several factors have been proposed to explain these differences, including heterogeneity in the rates of species diversification and the age of clades. It has been frequently assumed that rapid rates of diversification are coupled to high rates of ecological and morphological evolution, leading to a prediction that remains poorly explored for most species: the positive association between ecological niche divergence, morphological evolution and species diversification. We combined a time-calibrated phylogeny with distribution, ecological and body size data for scaly tree ferns (Cyatheaceae) to test whether rates of species diversification are predicted by the rates at which clades have evolved distinct ecological niches and body sizes. We found that rates of species diversification are positively correlated with rates of ecological and morphological evolution, with rapidly diversifying clades also showing rapidly evolving ecological niches and body sizes. Our results show that rapid diversification of scaly tree ferns is associated with the evolution of species with comparable morphologies that diversified into similar, yet distinct, environments. This suggests parallel evolutionary pathways opening in different tropical regions whenever ecological and geographical opportunities arise. Accordingly, rates of ecological niche and body size evolution are relevant to explain the current patterns of species richness in this ‘ancient’ fern lineage across the tropics.

Fossil horses from “Eohippus” (Hyracotherium) to Equus: scaling, Cope's Law, and the evolution of body size

Paleobiology ◽  
1986 ◽  
Vol 12 (4) ◽  
pp. 355-369 ◽  
Author(s):  
Bruce J. MacFadden
Keyword(s):  
Body Size ◽  
Body Mass ◽  
Morphological Evolution ◽  
Natural Populations ◽  
Evolutionary Rates ◽  
Middle Pleistocene ◽  
Gradual Change ◽  
Regression Equations ◽  
Extant Species ◽  
Body Sizes

The evolution of body size in fossil horses is frequently depicted as a gradual, progressive trend toward increased body size (Cope's Law). Body size (actually body mass) was estimated for 40 species of fossil horses using dental and skeletal characters and regression equations derived from the same characters in extant species of Equus with known body mass. After body sizes were estimated, rates of morphological evolution, in darwins (d), were calculated between known ancestral and descendant fossil horse species. For the first half of horse evolution (from ca. 57 to 25 ma) body mass remained relatively static between about 25 and 50 kg with very slow evolutionary rates of 0.003–0.04 d. During the early–middle Miocene (from ca. 25 to 10 ma) there was a major diversification of body mass to about 75–400 kg and consistently higher evolutionary rates between 0.04 and 0.24 d. Since the late Miocene, body mass has generally increased with a maximum seen (in natural populations) in Equus scotti (ca. 500 kg) during the middle Pleistocene. Therefore, for horses, the traditional interpretation of gradual increase in body size through time is oversimplified because: (1) although the exception to the rule, 5 of 24 species lineages studied are characterized by dwarfism; and (2) the general trend seems to have been a long period (32 ma) of relative stasis followed by 25 ma of diversification and progressive (although not necessarily gradual) change in body size.

scholarly journals Arboreality constrains morphological evolution but not species diversification in vipers

2017 ◽  
Vol 284 (1869) ◽  
pp. 20171775 ◽  
Author(s):  
Laura Rodrigues Vieira de Alencar ◽  
Marcio Martins ◽  
Gustavo Burin ◽  
Tiago Bosisio Quental
Keyword(s):  
New Species ◽  
Body Size ◽  
Morphological Evolution ◽  
Trait Evolution ◽  
Morphological Diversification ◽  
Body Sizes ◽  
Speciation Rates ◽  
Slender Bodies ◽  
Morphological Variants ◽  
Arboreal Snakes

An increase in ecological opportunities, either through changes in the environment or acquisition of new traits, is frequently associated with an increase in species and morphological diversification. However, it is possible that certain ecological settings might prevent lineages from diversifying. Arboreality evolved multiple times in vipers, making them ideal organisms for exploring how potentially new ecological opportunities affect their morphology and speciation regimes. Arboreal snakes are frequently suggested to have a very specialized morphology, and being too large, too small, too heavy, or having short tails might be challenging for them. Using trait-evolution models, we show that arboreal vipers are evolving towards intermediate body sizes, with longer tails and more slender bodies than terrestrial vipers. Arboreality strongly constrains body size and circumference evolution in vipers, while terrestrial lineages are evolving towards a broader range of morphological variants. Trait-dependent diversification models, however, suggest similar speciation rates between microhabitats. Thus, we show that arboreality might constrain morphological evolution but not necessarily affect the rates at which lineages generate new species.

scholarly journals Giant Mesozoic coelacanths (Osteichthyes, Actinistia) reveal high body size disparity decoupled from taxic diversity

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Lionel Cavin ◽  
André Piuz ◽  
Christophe Ferrante ◽  
Guillaume Guinot
Keyword(s):  
Body Size ◽  
Fossil Record ◽  
Morphological Evolution ◽  
Small Species ◽  
High Body ◽  
Large Size ◽  
Living Fossils ◽  
Size Disparity ◽  
Speciation Rates ◽  
Taxic Diversity

AbstractThe positive correlation between speciation rates and morphological evolution expressed by body size is a macroevolutionary trait of vertebrates. Although taxic diversification and morphological evolution are slow in coelacanths, their fossil record indicates that large and small species coexisted, which calls into question the link between morphological and body size disparities. Here, we describe and reassess fossils of giant coelacanths. Two genera reached up to 5 m long, placing them among the ten largest bony fish that ever lived. The disparity in body size adjusted to taxic diversity is much greater in coelacanths than in ray-finned fishes. Previous studies have shown that rates of speciation and rates of morphological evolution are overall low in this group, and our results indicate that these parameters are decoupled from the disparity in body size in coelacanths. Genomic and physiological characteristics of the extant Latimeria may reflect how the extinct relatives grew to such a large size. These characteristics highlight new evolutionary traits specific to these “living fossils”.

scholarly journals Morphological evolution in the ant reproductive caste

2020 ◽  
Author(s):  
Raquel Divieso ◽  
Thiago S. R. Silva ◽  
Marcio R. Pie
Keyword(s):  
Body Size ◽  
Morphological Variation ◽  
Morphological Evolution ◽  
Division Of Labour ◽  
Comprehensive Treatment ◽  
Size Distributions ◽  
Reproductive Division Of Labour ◽  
Evolution Of Eusociality ◽  
Worker Caste ◽  
Reproductive Division

AbstractThe evolution of eusociality led to severe changes in the general hymenopteran body plan. In particular, the evolution of reproductive division of labour caused the worker caste to be largely freed from the demands involved in reproduction. As a consequence, workers were able to evolve highly specialized morphologies for foraging and colony maintenance, whereas the reproductive caste became specialized for reproduction. Despite these important changes, little is known about general patterns of morphological evolution within the ant reproductive caste. Our goals were to characterize morphological variation in the ant reproductive caste and to test whether different sexes display variation in their evolutionary rates. We obtained measurements of 897 specimens from a total of 678 ant species. The shapes of the size distributions were similar between sexes, with queens being larger than males in all traits except for eye length. Contrary to the expectation based on Rensch’s rule, although queens were larger, the degree of dimorphism increased with body size. Finally, there is strong evidence for an accelerated tempo of morphological evolution in queens in relation to males. These results represent the first comprehensive treatment of morphological variation in the ant reproductive caste and provide important new insights into their evolution.

Evolutionary and allometric insights into anuran auditory sensitivity and morphology

2021 ◽  
Author(s):  
Logan S. James ◽  
Ryan C Taylor ◽  
Kimberly L Hunter ◽  
Michael J Ryan
Keyword(s):  
Body Size ◽  
Communication Systems ◽  
Information Transfer ◽  
Morphological Evolution ◽  
Preliminary Evidence ◽  
Dominant Frequency ◽  
Scaling Effects ◽  
Hearing Sensitivity ◽  
Behavioral Systems ◽  
As Species

As species change through evolutionary time, the neurological and morphological structures that underly behavioral systems typically remain coordinated. This is especially important for communication systems, in which these structures must remain coordinated both within and between senders and receivers for successful information transfer. The acoustic communication of anurans (“frogs”) offers an excellent system to ask when and how such coordination is maintained, and to allow researchers to dissociate allometric effects from independent correlated evolution. Anurans constitute one of the most speciose groups of vocalizing vertebrates and females typically rely on vocalizations to localize males for reproduction. Here, we compile and compare data on various aspects of auditory morphology, hearing sensitivity and call dominant frequency across 81 species of anurans. We find robust, phylogenetically independent scaling effects of body size for all features measured. Furthermore, after accounting for body size, we find preliminary evidence that morphological evolution beyond allometry can correlate with hearing sensitivity and dominant frequency. These data provide foundational results regarding constraints imposed by body size on communication systems and motivate further data collection and analysis using comparative approaches across the numerous anuran species.

scholarly journals Morphological evolution in the ant reproductive caste

2020 ◽  
Vol 131 (3) ◽  
pp. 465-475
Author(s):  
Raquel Divieso ◽  
Thiago S R Silva ◽  
Marcio R Pie
Keyword(s):  
Body Size ◽  
Morphological Variation ◽  
Morphological Evolution ◽  
Division Of Labour ◽  
Comprehensive Treatment ◽  
Size Distributions ◽  
Reproductive Division Of Labour ◽  
Evolution Of Eusociality ◽  
Worker Caste ◽  
Reproductive Division

Abstract The evolution of eusociality has led to considerable changes in the general hymenopteran body plan. In particular, the evolution of reproductive division of labour caused the worker caste to be largely freed from the demands involved in reproduction. As a consequence, workers were able to evolve highly specialized morphologies for foraging and colony maintenance, whereas the reproductive caste became specialized for reproduction. Despite these important changes, little is known about the general patterns of morphological evolution within the ant reproductive caste. Our goals here were to characterize morphological variation in the ant reproductive caste and to test whether different sexes display variation in their evolutionary rates. We obtained measurements of 897 specimens from a total of 678 ant species. The shapes of the size distributions were similar between sexes, with queens being larger than males in all traits except for eye length. Contrary to the expectation based on Rensch’s rule, although queens were larger, the degree of dimorphism increased with body size. Finally, there was strong evidence for an accelerated tempo of morphological evolution in queens in relation to males. These results represent the first comprehensive treatment of morphological variation in the ant reproductive caste and provide important new insights into their evolution.

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