scholarly journals Fish Diversity as a Function of Depth and Body Size

2017 ◽  
Author(s):  
Klaus M. Stiefel ◽  
Timothy Joseph R. Quimpo
Keyword(s):  
Body Size ◽  
Fish Species ◽  
Scaling Laws ◽  
Large Body ◽  
Neutral Theory ◽  
Fish Diversity ◽  
Large Species ◽  
Species Numbers ◽  
Body Sizes ◽  
Reduced Rate

AbstractWe analyze the number of marine fish species as a function of fish body size and occurrence depth. For this purpose, we analyze the FishBase database. We compare these data to predictions of fish species numbers derived from the neutral theory of biodiversity combined with well-established ecological scaling laws, and measured oceanic biomass data. We consider several variants of these scaling laws, and we find that more large fish species exist compared to the prediction, which is especially true for elasmobranchs, possibly due to their overwhelmingly predatory niches. We find species numbers decreasing with occurrence depth somewhat quicker than our predictions based on the decrease of the number of individuals with depth indicates. This is especially true for the elasmobranchs. This is unsurprising, since the individuals versus depth data did not specifically determine elasmobranch biomass, and since sharks are known to be limited to depths < 3,000 m.Finally, we discuss how a reduced rate of speciation in larger animals could explain why large species are rare, in spite of the advantages of large body sizes outlined in Cope’s rule.

Primary productivity, deoxygenation, and the Gulliver-absence effect determine bivalve body size following the end-Permian mass extinction

2020 ◽  
Author(s):  
Melanie Tietje ◽  
William J. Foster ◽  
Jana Gliwa ◽  
Clara Lembke ◽  
Autumn Pugh ◽  
...  
Keyword(s):  
Body Size ◽  
Ocean Circulation ◽  
Mass Extinction ◽  
The Body ◽  
Large Species ◽  
Mass Extinctions ◽  
Shell Size ◽  
Body Sizes ◽  
Permian Mass Extinction ◽  
The Impact

&lt;p&gt; The impact of mass extinctions on the body sizes of animals has received considerable attention and debate, as to whether the reduced size of post-extinction organisms is due to the selective extinction of large species, absence of large species as a stochastic effect of low-diversity faunas, or a size decrease within surviving genera and species. Here, we investigated the body sizes of bivalves following the end-Permian mass extinction event and show that the shell size increase of bivalve genera was driven by both evolutionary and ecophenotypic responses. First, some genera&amp;#160;show significant increases in body size with the evolution of new species. Further, the same genera record significant within-species increases in average and maximum body size into the late Induan, indicating that ecophenotypic changes were also involved on long-term body size trends. These increases are associated with invigorated ocean circulation, improved oxygenation of the seafloor, and probably increased food supply.&lt;/p&gt;

scholarly journals Size- and sex-specific predation on dung flies by amphibian and arthropod predators – size match matters

2019 ◽  
Author(s):  
Wolf U. Blanckenhorn ◽  
Gabriele Cozzi ◽  
Gregory Jäggli ◽  
Juan Pablo Busso
Keyword(s):  
Body Size ◽  
Sexual Size Dimorphism ◽  
Rana Temporaria ◽  
Large Body ◽  
Mechanistic Study ◽  
Mating Activity ◽  
Size Dimorphism ◽  
Arthropod Predators ◽  
Body Sizes ◽  
Predation Rates

Because predator-prey interactions in nature are multifarious, linking phenomenological predation rates to the underlying behavioural or ecological mechanisms is challenging. Size- and sex-specific predation has been implicated as a major selective force keeping animals small, affecting the evolution of body size and sexual size dimorphism. We experimentally assessed predation by various amphibian (frogs and toads) and arthropod predators (bugs, flies, spiders) on three species of dung flies with similar ecology but contrasting body sizes, sexual size dimorphism and coloration. Predators were offered a size range of flies in single- or mixed-sex groups. As expected based on optimal foraging theory, some anurans (e.g. Bufo bufo) selected larger prey, thus selecting against large body size of the flies, while others (Bombina variagata and Rana esculenta) showed no such pattern. Small juvenile Rana temporaria metamorphs, in contrast, preferred small flies, as did all arthropod predators, a pattern that can be explained by larger prey being better at escaping. The more mobile males were not eaten more frequently or faster than the cryptic females, even when conspicuously colored. Predation rates on flies in mixed groups permitting mating activity were not higher, contrary to expectation, nor was predation generally sex-specific. We conclude that the size-selectivity of predators, and hence the viability selection pattern exerted on their prey, depends foremost on the relative body sizes of the two in a continuous fashion. Sex-specific predation by single predators appears to contribute little to sexual dimorphism. Therefore, the mechanistic study of predation requires integration of both the predator’s and the prey’s perspectives, and phenomenological field studies of predation remain indispensable.

“She was neither unduly fat nor lanky”: Representation of body size and beauty in the novels of Daniel O. Fágúnwà

2020 ◽  
Vol 18 (1) ◽  
pp. 131-147
Author(s):  
Fausat Motunrayo Ibrahim ◽  
Ayodele S. Jegede
Keyword(s):  
Body Size ◽  
Large Body ◽  
African Literature ◽  
Thin Structure ◽  
Self Worth ◽  
Body Sizes ◽  
Definition Of

The climate of thought regarding beauty characterization among Africans and other people of colour portrays the large body as beautiful. This reflects that body size and beauty is racially and culturally expressive, making it apposite to be disparate in advancing related discourses. This is particularly important because such discourses can influence Africans’ evaluation of their self-worth. The concerns generated by the global rise in obesity further create interest in these issues. African literature offers a fine and disparate platform to understand social realities. Consequently, relevant contents of the five precedent Yorùbá novels of Daniel Fágúnwà including Igbó Olódùmarè, Ìrèké Oníbùdó,Ògbójú ọdẹ nínú Igbó Irúnmọlè, Ìrìnkèrindò nínú Igbó Elégbèje and Àdììtú Olódùmarè were extracted and analyzed to examine association of beauty with body sizes. Findings reflect more of bipolarity in the definition of beauty, such that the none-fat/none-thin structure is conveyed as beautiful. Concurrently, the fat and the thin is also portrayed as beautiful, making ‘body size’ definition of beauty to be elusive, and strongly suggesting neutrality to body size among the Yorùbá. This is strongly borne out of Fágúnwà’s and indeed, Yorùbá construction of beauty from a ‘character’ perspective. Character (ìwà) is staunchly expounded as constituting beauty. The beautiful body size is indeterminate in Fágúnwà’s narratives and indeed, in Yorùbá thought.

Prey preference of a wasp determined by nest size supports the role of natural selection in body size evolution in Cassidinae leaf beetles

2021 ◽  
Author(s):  
Tadashi Shinohara ◽  
Yasuoki Takami
Keyword(s):  
Body Size ◽  
Natural Selection ◽  
Prey Species ◽  
Large Body ◽  
Size Variation ◽  
Prey Preference ◽  
Nest Size ◽  
Large Prey ◽  
Leaf Beetles ◽  
Body Sizes

Abstract The prey preference of a predator can impose natural selection on prey phenotypes, including body size. Despite evidence that large body size protects against predation in insects, the determinants of body size variation in Cassidinae leaf beetles are not well understood. We examined the prey preference of the digger wasp Cerceris albofasciata, a specialist predator of adult Cassidinae leaf beetles, and found evidence for natural selection on prey body size. The wasp hunted prey smaller than the size of their nest entrance. However, the wasp preferred larger prey species among those that could be carried into their nest. Thus, the benefits of large prey and the cost associated with nest expansion might determine the prey size preference. As expected from the prey species preference, the wasp preferred small individuals of the largest prey species, Thlaspida biramosa, and large individuals of the smallest prey species, Cassida piperata, resulting in natural selection on body sizes. In intermediate-sized prey species, however, there was no evidence for selection on body size. Natural selection on body size might explain the variation of prey morphologies that increase body size, such as explanate margins, in this group.

Traditional Attenuation of Inequality: Neutral Meaning of Body Size among the Yorùbá of Southwestern Nigeria

2020 ◽  
pp. 1-25
Author(s):  
Fausat M. Ibrahim ◽  
Ayodele S. Jegede
Keyword(s):  
Body Size ◽  
Phenomenological Study ◽  
Large Body ◽  
Human Person ◽  
Group Discussions ◽  
Southwestern Nigeria ◽  
Good Person ◽  
Body Sizes ◽  
Globalized World ◽  
Depth Interviews

Abstract Body size is a profound ground of inequality in modern global society. Moreover, constructions of body size are racially polarized, with blacks being reputed for venerating large body. Proceeding with a triangulation of qualitative methods, this phenomenological study featured forty-two in-depth interviews, eight focus group discussions and eighteen key informant interviews among men and women of varying body sizes in two of the six states of southwestern Nigeria. Findings reflect dominantly neutral meaning of body size among the Yorùbá. This neutrality is dominantly reflected in the literal questioning of meaning that Yorùbá attach to body size, and who becomes a king in Yorùbá land but partially neutral in acceptability of prospective son or daughter in-law. Divinity, orí (fate), ìwà (good behavior) and ọmọlúàbí (good person) are among phenomena that counts in discerning people’s worth. Meaning attached to body size is opposed to common-place attitude to body size, making this attitude to be profane while meaning is solemn. This meaning is tremendously in favour of optimum health, and attenuating inequality, for which even black societies are perpetrating in the globalized world. Traditional Yorùbá value of human person is irrespective of body size.

scholarly journals TP53 copy number expansion is associated with the evolution of increased body size and an enhanced DNA damage response in elephants

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Michael Sulak ◽  
Lindsey Fong ◽  
Katelyn Mika ◽  
Sravanthi Chigurupati ◽  
Lisa Yon ◽  
...  
Keyword(s):  
Dna Damage ◽  
Body Size ◽  
Signaling Pathway ◽  
Copy Number ◽  
Large Body ◽  
Genotoxic Stress ◽  
Suppressor Gene ◽  
Direct Role ◽  
Increased Risk ◽  
Body Sizes

A major constraint on the evolution of large body sizes in animals is an increased risk of developing cancer. There is no correlation, however, between body size and cancer risk. This lack of correlation is often referred to as 'Peto's Paradox'. Here, we show that the elephant genome encodes 20 copies of the tumor suppressor gene TP53 and that the increase in TP53 copy number occurred coincident with the evolution of large body sizes, the evolution of extreme sensitivity to genotoxic stress, and a hyperactive TP53 signaling pathway in the elephant (Proboscidean) lineage. Furthermore, we show that several of the TP53 retrogenes (TP53RTGs) are transcribed and likely translated. While TP53RTGs do not appear to directly function as transcription factors, they do contribute to the enhanced sensitivity of elephant cells to DNA damage and the induction of apoptosis by regulating activity of the TP53 signaling pathway. These results suggest that an increase in the copy number of TP53 may have played a direct role in the evolution of very large body sizes and the resolution of Peto's paradox in Proboscideans.

scholarly journals Predation selectively culls medium-sized species from island mammal faunas

2014 ◽  
Vol 10 (4) ◽  
pp. 20131066 ◽  
Author(s):  
Emily Hanna ◽  
Marcel Cardillo
Keyword(s):  
Body Size ◽  
Extinction Risk ◽  
Large Body ◽  
Conservation Strategies ◽  
Size Selectivity ◽  
Introduced Predators ◽  
Body Sizes ◽  
Mammal Faunas ◽  
Species Declines ◽  
Risk Association

Globally, elevated extinction risk in mammals is strongly associated with large body size. However, in regions where introduced predators exert strong top-down pressure on mammal populations, the selectivity of extinctions may be skewed towards species of intermediate body size, leading to a hump-shaped relationship between size and extinction risk. The existence of this kind of extinction pattern, and its link to predation, has been contentious and difficult to demonstrate. Here, we test the hypothesis of a hump-shaped body size–extinction relationship, using a database of 927 island mammal populations. We show that the size-selectivity of extinctions on many islands has exceeded that expected under null models. On islands with introduced predators, extinctions are biased towards intermediate body sizes, but this bias does not occur on islands without predators. Hence, on islands with a large-bodied mammal fauna, predators are selectively culling species from the lower end of the size distribution, and on islands with a small-bodied fauna they are culling species from the upper end. These findings suggest that it will be difficult to use predictable generalizations about extinction patterns, such as a positive body size–extinction risk association, to anticipate future species declines and plan conservation strategies accordingly.

scholarly journals Large neotheropods from the Upper Triassic of North America and the early evolution of large theropod body sizes

2019 ◽  
Vol 93 (5) ◽  
pp. 1010-1030 ◽  
Author(s):  
Christopher T. Griffin
Keyword(s):  
Body Size ◽  
Phylogenetic Analyses ◽  
Large Body ◽  
Upper Triassic ◽  
Early Evolution ◽  
Phylogenetic Position ◽  
Ancestral State ◽  
Femur Length ◽  
Theropod Dinosaurs ◽  
Body Sizes

AbstractLarge body sizes among nonavian theropod dinosaurs is a major feature in the evolution of this clade, with theropods reaching greater sizes than any other terrestrial carnivores. However, the early evolution of large body sizes among theropods is obscured by an incomplete fossil record, with the largest Triassic theropods represented by only a few individuals of uncertain ontogenetic stage. Here I describe two neotheropod specimens from the Upper Triassic Bull Canyon Formation of New Mexico and place them in a broader comparative context of early theropod anatomy. These specimens possess morphologies indicative of ontogenetic immaturity (e.g., absence of femoral bone scars, lack of co-ossification between the astragalus and calcaneum), and phylogenetic analyses recover these specimens as early-diverging neotheropods in a polytomy with other early neotheropods at the base of the clade. Ancestral state reconstruction for body size suggests that the ancestral theropod condition was small (~240 mm femur length), but the ancestral neotheropod was larger (~300–340 mm femur length), with coelophysoids experiencing secondary body size reduction, although this is highly dependent on the phylogenetic position of a few key taxa. Theropods evolved large body sizes before the Triassic–Jurassic extinction, as hypothesized in most other ancestral state reconstructions of theropod body sizes, but remained rare relative to smaller theropods until the Jurassic.

scholarly journals The paradox of inverted biomass pyramids in kelp forest fish communities

2016 ◽  
Vol 283 (1833) ◽  
pp. 20160816 ◽  
Author(s):  
Rowan Trebilco ◽  
Nicholas K. Dulvy ◽  
Sean C. Anderson ◽  
Anne K. Salomon
Keyword(s):  
Body Size ◽  
Trophic Position ◽  
Small Body ◽  
Large Body ◽  
Kelp Forest ◽  
Fish Communities ◽  
Reef Fishes ◽  
Fish Muscle ◽  
Mass Ratio ◽  
Body Sizes

Theory predicts that bottom-heavy biomass pyramids or ‘stacks’ should predominate in real-world communities if trophic-level increases with body size (mean predator-to-prey mass ratio (PPMR) more than 1). However, recent research suggests that inverted biomass pyramids (IBPs) characterize relatively pristine reef fish communities. Here, we estimated the slope of a kelp forest fish community biomass spectrum from underwater visual surveys. The observed biomass spectrum slope is strongly positive, reflecting an IBP. This is incongruous with theory because this steep positive slope would only be expected if trophic position decreased with increasing body size (consumer-to-resource mass ratio, less than 1). We then used δ 15 N signatures of fish muscle tissue to quantify the relationship between trophic position and body size and instead detected strong evidence for the opposite, with PPMR ≈ 1650 (50% credible interval 280–12 000). The natural history of kelp forest reef fishes suggests that this paradox could arise from energetic subsidies in the form of movement of mobile consumers across habitats, and from seasonally pulsed production inputs at small body sizes. There were four to five times more biomass at large body sizes (1–2 kg) than would be expected in a closed steady-state community providing a measure of the magnitude of subsidies.

Giant snakes in tropical forests: a field study of the Australian scrub python, Morelia kinghorni

2005 ◽  
Vol 32 (2) ◽  
pp. 193 ◽  
Author(s):  
S. Fearn ◽  
L. Schwarzkopf ◽  
R. Shine
Keyword(s):  
Body Size ◽  
Field Study ◽  
Large Body ◽  
Adult Males ◽  
Heating Rates ◽  
Wet Season ◽  
Ecological Data ◽  
Eastern Australia ◽  
Body Sizes ◽  
Initial Capture

Studies on species that attain very large body sizes provide a powerful opportunity to clarify the ecological correlates and consequences of body size, but logistical obstacles mean that most ‘giant’ species have attracted little field-based research. The Australian scrub python, Morelia kinghorni (= M. amethistina in earlier literature), is the largest Australian snake. Our three-year field study in the Tully River Gorge of tropical north-eastern Australia provides the first detailed ecological data on this species. Snakes aggregate in the gorge during the dry season for reproductive activities (combat, courtship and mating), and these aggregations consist primarily of large adult males. Wet-season samples from a nearby road contained more females, and more juvenile animals. Body temperatures of diurnally active pythons averaged 25.2°C, and were highly correlated with air and substrate temperatures. Larger snakes were cooler than smaller conspecifics, perhaps reflecting their slower heating rates. Recapture of marked individuals suggests that pythons of both sexes and all body sizes maintain fixed home ranges, as the distance from initial capture did not increase through time; most animals were recaptured <100 m from their initial capture point, but some dispersed at least 1.5 km. Adult male pythons spanned a massive range in body sizes (1.3–3.76 m in snout–vent length, 0.30–11 kg in mass), and larger males were more likely to engage in combat, exhibit combat-related injuries (bite wounds) and obtain matings. Presumably reflecting the reproductive advantage of larger body size, males attained much larger maximum sizes than did females within our study population.

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