scholarly journals Independent evolution of baleen whale gigantism linked to Plio-Pleistocene ocean dynamics

2017 ◽  
Vol 284 (1855) ◽  
pp. 20170546 ◽  
Author(s):  
Graham J. Slater ◽  
Jeremy A. Goldbogen ◽  
Nicholas D. Pyenson
Keyword(s):  
Body Size ◽  
Evolutionary Dynamics ◽  
Niche Partitioning ◽  
Ocean Dynamics ◽  
Baleen Whales ◽  
The Past ◽  
Large Size ◽  
Size Evolution ◽  
Primary Determinant ◽  
Quantitative Examination

Vertebrates have evolved to gigantic sizes repeatedly over the past 250 Myr, reaching their extreme in today's baleen whales (Mysticeti). Hypotheses for the evolution of exceptionally large size in mysticetes range from niche partitioning to predator avoidance, but there has been no quantitative examination of body size evolutionary dynamics in this clade and it remains unclear when, why or how gigantism evolved. By fitting phylogenetic macroevolutionary models to a dataset consisting of living and extinct species, we show that mysticetes underwent a clade-wide shift in their mode of body size evolution during the Plio-Pleistocene. This transition, from Brownian motion-like dynamics to a trended random walk towards larger size, is temporally linked to the onset of seasonally intensified upwelling along coastal ecosystems. High prey densities resulting from wind-driven upwelling, rather than abundant resources alone, are the primary determinant of efficient foraging in extant mysticetes and Late Pliocene changes in ocean dynamics may have provided an ecological pathway to gigantism in multiple independent lineages.

scholarly journals Rates and modes of body size evolution in early carnivores and herbivores: a case study from Captorhinidae

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e1555 ◽  
Author(s):  
Neil Brocklehurst
Keyword(s):  
Body Size ◽  
Rate Variation ◽  
Basal Node ◽  
Rates Of Evolution ◽  
Size Evolution ◽  
High Fibre ◽  
Body Sizes ◽  
Adaptive Peak ◽  
Quantitative Examination ◽  
Body Size Evolution

Body size is an extremely important characteristic, impacting on a variety of ecological and life-history traits. It is therefore important to understand the factors which may affect its evolution, and diet has attracted much interest in this context. A recent study which examined the evolution of the earliest terrestrial herbivores in the Late Carboniferous and Early Permian concluded that in the four herbivorous clades examined there was a trend towards increased body size, and that this increase was more substantial than that observed in closely related carnivorous clades. However, this hypothesis was not based on quantitative examination, and phylogenetic comparative methods provide a more robust means of testing such hypotheses. Here, the evolution of body size within different dietary regimes is examined in Captorhinidae, the most diverse and longest lived of these earliest high fibre herbivores. Evolutionary models were fit to their phylogeny to test for variation in rate and mode of evolution between the carnivorous and herbivorous members of this clade, and an analysis of rate variation throughout the tree was carried out. Estimates of ancestral body sizes were calculated in order to compare the rates and direction of evolution of lineages with different dietary regimes. Support for the idea that the high fibre herbivores within captorhinids are being drawn to a higher adaptive peak in body size than the carnivorous members of this clade is weak. A shift in rates of body size evolution is identified, but this does not coincide with the evolution of high-fibre herbivory, instead occurring earlier in time and at a more basal node. Herbivorous lineages which show an increase in size are not found to evolve at a faster rate than those which show a decrease; in fact, it is those which experience a size decrease which evolve at higher rates. It is possible the shift in rates of evolution is related to the improved food processing ability of the more derived captorhinids rather than a shift in diet, but the evidence for this is circumstantial.

scholarly journals Rates and modes of body size evolution in early carnivores and herbivores: a case study from Captorhinidae

2015 ◽  
Author(s):  
Neil Brocklehurst
Keyword(s):  
Body Size ◽  
Rate Variation ◽  
Basal Node ◽  
Rates Of Evolution ◽  
Size Evolution ◽  
High Fibre ◽  
Body Sizes ◽  
Adaptive Peak ◽  
Quantitative Examination ◽  
Body Size Evolution

Body size is an extremely important characteristic, impacting on a variety of ecological and life-history traits. It is therefore important to understand the factors which may affect its evolution, and diet has attracted much interest in this context. A recent study, examining the evolution of the earliest terrestrial herbivores in the Late Carboniferous and Early Permian, concluded that in the four herbivorous clades examined there was a trend towards increased body size, and that this increase was more substantial than that observed in closely related carnivorous clades. However, this hypothesis was not based on quantitative examination, and phylogenetic comparative methods provide a more robust means of testing such hypotheses. Here, the evolution of body size within different dietary regimes is examined in Captorhinidae, the most diverse and longest lived of these earliest high fibre herbivores. Evolutionary models were fit to their phylogeny to test for variation in rate and mode of evolution between the carnivorous and herbivorous members of this clade, and an analysis of rate variation throughout the tree was carried out. Estimates of ancestral body sizes were calculated in order to compare the rates and direction of evolution of lineages with different dietary regimes. Support for the idea that the high fibre herbivores within captorhinids are being drawn to a higher adaptive peak in body size than the carnivorous members of this clade is weak. A shift in rates of body size evolution is identified, but this does not coincide with the evolution of high-fibre herbivory, instead occurring earlier in time and at a more basal node. Herbivorous lineages which show an increase in size are not found to evolve at a faster rate than those which show a decrease; in fact it is those which experience a size decrease which evolve at significantly higher rates. The opposite is true of the carnivorous lineages, suggesting that in captorhinids it is the carnivores which show the greater trend towards increased body size. It is possible the shift in rates of evolution is related to the improved food processing ability of the more derived captorhinids rather than a shift in diet, but the evidence for this is circumstantial.

The Island of Extremes: Giants and Dwarfs on a Small Remote Island

2021 ◽  
Vol 28 (4) ◽  
pp. 225-230
Author(s):  
Yuval Itescu ◽  
Johannes Foufopoulos ◽  
Rachel Schwarz ◽  
Petros Lymberakis ◽  
Alex Slavenko ◽  
...  
Keyword(s):  
Body Size ◽  
Natural Selection ◽  
Aegean Sea ◽  
Large Size ◽  
Size Evolution ◽  
Remote Island ◽  
Body Size Evolution ◽  
Remote Islands ◽  
First Time ◽  
Defensive Mechanism

Body size evolution on islands is widely studied and hotly debated. Gigantism and dwarfism are thought to evolve under strong natural selection, especially on small remote islands. We report a curious co-occurrence of both dwarf and giant lizards on the same small, remote island (Plakida): the largest Podarcis erhardii (Lacertidae) and smallest Mediodactylus kotschyi sensu lato; Gekkonidae — the two commonest insular reptiles in the Aegean Sea. The geckos of Plakida have a peculiar tail-waving behavior, documented here for the first time in this genus. We suspect that P. erhardii evolved large size to consume geckos and the geckos evolved a unique tail-waving behavior as a defensive mechanism.

scholarly journals Rates and modes of body size evolution in early carnivores and herbivores: a case study from Captorhinidae

2015 ◽  
Author(s):  
Neil Brocklehurst
Keyword(s):  
Body Size ◽  
Rate Variation ◽  
Basal Node ◽  
Rates Of Evolution ◽  
Size Evolution ◽  
High Fibre ◽  
Body Sizes ◽  
Adaptive Peak ◽  
Quantitative Examination ◽  
Body Size Evolution

Body size is an extremely important characteristic, impacting on a variety of ecological and life-history traits. It is therefore important to understand the factors which may affect its evolution, and diet has attracted much interest in this context. A recent study, examining the evolution of the earliest terrestrial herbivores in the Late Carboniferous and Early Permian, concluded that in the four herbivorous clades examined there was a trend towards increased body size, and that this increase was more substantial than that observed in closely related carnivorous clades. However, this hypothesis was not based on quantitative examination, and phylogenetic comparative methods provide a more robust means of testing such hypotheses. Here, the evolution of body size within different dietary regimes is examined in Captorhinidae, the most diverse and longest lived of these earliest high fibre herbivores. Evolutionary models were fit to their phylogeny to test for variation in rate and mode of evolution between the carnivorous and herbivorous members of this clade, and an analysis of rate variation throughout the tree was carried out. Estimates of ancestral body sizes were calculated in order to compare the rates and direction of evolution of lineages with different dietary regimes. Support for the idea that the high fibre herbivores within captorhinids are being drawn to a higher adaptive peak in body size than the carnivorous members of this clade is weak. A shift in rates of body size evolution is identified, but this does not coincide with the evolution of high-fibre herbivory, instead occurring earlier in time and at a more basal node. Herbivorous lineages which show an increase in size are not found to evolve at a faster rate than those which show a decrease; in fact it is those which experience a size decrease which evolve at significantly higher rates. The opposite is true of the carnivorous lineages, suggesting that in captorhinids it is the carnivores which show the greater trend towards increased body size. It is possible the shift in rates of evolution is related to the improved food processing ability of the more derived captorhinids rather than a shift in diet, but the evidence for this is circumstantial.

Dinosaur Macroevolution and Macroecology

2018 ◽  
Vol 49 (1) ◽  
pp. 379-408 ◽  
Author(s):  
Roger B.J. Benson
Keyword(s):  
Life History ◽  
Body Size ◽  
Reproductive Biology ◽  
Fossil Record ◽  
Structural Diversity ◽  
Body Plan ◽  
Adaptive Landscape ◽  
Species Diversification ◽  
Size Evolution ◽  
Body Size Evolution

Dinosaurs were large-bodied land animals of the Mesozoic that gave rise to birds. They played a fundamental role in structuring Jurassic–Cretaceous ecosystems and had physiology, growth, and reproductive biology unlike those of extant animals. These features have made them targets of theoretical macroecology. Dinosaurs achieved substantial structural diversity, and their fossil record documents the evolutionary assembly of the avian body plan. Phylogeny-based research has allowed new insights into dinosaur macroevolution, including the adaptive landscape of their body size evolution, patterns of species diversification, and the origins of birds and bird-like traits. Nevertheless, much remains unknown due to incompleteness of the fossil record at both local and global scales. This presents major challenges at the frontier of paleobiological research regarding tests of macroecological hypotheses and the effects of dinosaur biology, ecology, and life history on their macroevolution.

scholarly journals The developmental and physiological basis of body size evolution in an insect

2001 ◽  
Vol 268 (1476) ◽  
pp. 1589-1593 ◽  
Author(s):  
Louis J. D'Amico ◽  
Goggy Davidowitz ◽  
H. Frederik Nijhout
Keyword(s):  
Body Size ◽  
Physiological Basis ◽  
Size Evolution ◽  
Body Size Evolution
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