scholarly journals Biomass of a trophic level increases with maximum body size, but less than proportionally

2020 ◽  
Author(s):  
Henrique C. Giacomini
Keyword(s):  
Body Size ◽  
Trophic Level ◽  
Maximum Size ◽  
Global Scale ◽  
Ecosystem Functions ◽  
Total Biomass ◽  
Metabolic Scaling ◽  
The Individual ◽  
Maximum Body ◽  
Maximum Body Size

A recent paper by Enquist and colleagues1 took a very important step in predicting the ecosystemic effects of species losses on a global scale. Using Metabolic Scaling Theory (MST), they concluded that large-sized species contribute disproportionately to several ecosystem functions. One of their key predictions is that total biomass of animals in a trophic level (MTot, using their notation) should increase more than proportionally with its maximum body size (mmax), following the relationship MTot ∝ mmax5/4. Here I argue that this superlinear scaling results from an incorrect representation of the individual size distribution and that the exponent should be 1/4, implying a sublinear scaling. The same reasoning applies to total energy flux or metabolism BTot, which should be invariant to maximum size according to the energetic equivalence and perfect compensatory responses entailed by MST.

scholarly journals Redescription of Ochmacanthus batrachostoma (Miranda-Ribeiro, 1912) (Siluriformes: Trichomycteridae): a possible case of incipient paedomorphism

2016 ◽  
Vol 14 (1) ◽  
Author(s):  
Caio S. Neto ◽  
Mário de Pinna
Keyword(s):  
Body Size ◽  
Internal Anatomy ◽  
Morphometric Traits ◽  
Type Specimens ◽  
Caudal Peduncle ◽  
Caudal Fin ◽  
Maximum Body ◽  
Maximum Body Size

ABSTRACT The lepidophagous stegophiline catfish Ochmacanthus batrachostoma (Miranda-Ribeiro, 1912) is endemic to the Paraná-Paraguai basin and is the only member of its genus in that drainage. It remains a poorly-known taxon mainly due to the historical scarcity of study specimens. The species is herein redescribed on the basis of type and non-type specimens from Brazil, Argentina and Paraguay. Ochmacanthus batrachostoma can be distinguished from congeners by the presence of long maxillary and rictal barbels, reduction of the posterior end of the caudal peduncle, a tadpole-like caudal fin and peduncle, among other morphometric traits and features of internal anatomy. Comparisons show that a number of unique traits of adult O. batrachostoma resemble conditions seen in juvenile specimens of other members of Stegophilinae. Such traits are also more pronounced in juveniles of O. batrachostoma itself. The species also has the smallest maximum body size in Ochmacanthus and among the smallest of any stegophiline. In combination, such observations suggest that the species is paedomorphic, although to a degree less extreme than seen in some other trichomycterids. This is the first possible case of paedomorphosis identified for stegophilines.

MAXIMUM BODY SIZE IN A RADIATING CLADE AS A FUNCTION OF TIME

Evolution ◽  
2005 ◽  
Vol 59 (5) ◽  
pp. 941
Author(s):  
Jerzy Trammer
Keyword(s):  
Body Size ◽  
Maximum Body ◽  
Maximum Body Size

scholarly journals Climate change and intensive land use reduce soil animal biomass via dissimilar pathways

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Rui Yin ◽  
Julia Siebert ◽  
Nico Eisenhauer ◽  
Martin Schädler
Keyword(s):  
Climate Change ◽  
Land Use ◽  
Body Size ◽  
Global Change ◽  
Ecosystem Functions ◽  
Total Biomass ◽  
Soil Animal ◽  
Soil Microarthropods ◽  
Density And Biomass ◽  
Intensive Land Use

Global change drivers, such as climate change and land use, may profoundly influence body size, density, and biomass of soil organisms. However, it is still unclear how these concurrent drivers interact in affecting ecological communities. Here, we present the results of an experimental field study assessing the interactive effects of climate change and land-use intensification on body size, density, and biomass of soil microarthropods. We found that the projected climate change and intensive land use decreased their total biomass. Strikingly, this reduction was realized via two dissimilar pathways: climate change reduced mean body size and intensive land use decreased density. These findings highlight that two of the most pervasive global change drivers operate via different pathways when decreasing soil animal biomass. These shifts in soil communities may threaten essential ecosystem functions like organic matter turnover and nutrient cycling in future ecosystems.

Perisesarma tuerkayi, a new species of mangrove crab from Vietnam (Decapoda, Brachyura, Sesarmidae), with an assessment of its phylogenetic relationships

Crustaceana ◽  
2017 ◽  
Vol 90 (7-10) ◽  
pp. 1155-1175 ◽  
Author(s):  
Adnan Shahdadi ◽  
Peter J. F. Davie ◽  
Christoph D. Schubart
Keyword(s):  
New Species ◽  
Body Size ◽  
Nuclear Dna ◽  
Congeneric Species ◽  
Southern Vietnam ◽  
Mangrove Crab ◽  
Large Maximum ◽  
Maximum Body ◽  
Maximum Body Size ◽  
A New Species

A new species ofPerisesarma,P. tuerkayi, is described from mangroves of Tan Thoi Island, southern Vietnam. Morphologically, the new species differs most significantly from congeners by the tuberculation pattern of the chelar dactylus, its unique G1 morphology, an unusually large maximum body size, and relatively short and broad ambulatory legs. Genetically,P. tuerkayin. sp. is markedly divergent from other congeneric species, both in mitochondrial and nuclear DNA. It is the fifth species ofPerisesarmareported from Vietnam.

scholarly journals Effects of allometry, productivity and lifestyle on rates and limits of body size evolution

2013 ◽  
Vol 280 (1764) ◽  
pp. 20131007 ◽  
Author(s):  
Jordan G. Okie ◽  
Alison G. Boyer ◽  
James H. Brown ◽  
Daniel P. Costa ◽  
S. K. Morgan Ernest ◽  
...  
Keyword(s):  
Body Size ◽  
Generation Time ◽  
Allometric Scaling ◽  
Empirical Work ◽  
Morphological Diversity ◽  
Maximum Size ◽  
Scaling Exponent ◽  
Size Evolution ◽  
Body Size Evolution ◽  
Maximum Body

Body size affects nearly all aspects of organismal biology, so it is important to understand the constraints and dynamics of body size evolution. Despite empirical work on the macroevolution and macroecology of minimum and maximum size, there is little general quantitative theory on rates and limits of body size evolution. We present a general theory that integrates individual productivity, the lifestyle component of the slow–fast life-history continuum, and the allometric scaling of generation time to predict a clade's evolutionary rate and asymptotic maximum body size, and the shape of macroevolutionary trajectories during diversifying phases of size evolution. We evaluate this theory using data on the evolution of clade maximum body sizes in mammals during the Cenozoic. As predicted, clade evolutionary rates and asymptotic maximum sizes are larger in more productive clades (e.g. baleen whales), which represent the fast end of the slow–fast lifestyle continuum, and smaller in less productive clades (e.g. primates). The allometric scaling exponent for generation time fundamentally alters the shape of evolutionary trajectories, so allometric effects should be accounted for in models of phenotypic evolution and interpretations of macroevolutionary body size patterns. This work highlights the intimate interplay between the macroecological and macroevolutionary dynamics underlying the generation and maintenance of morphological diversity.

Secular Changes in the Body Size of Non-Military Populations

1978 ◽  
Vol 22 (1) ◽  
pp. 616-616
Author(s):  
Howard W. Stoudt
Keyword(s):  
Health Care ◽  
Body Size ◽  
Western Europe ◽  
Economic Status ◽  
The Body ◽  
Past Century ◽  
The Past ◽  
Military Populations ◽  
Maximum Body ◽  
Maximum Body Size

People are getting bigger. Overall increases in body size can be documented for various worldwide populations for which adequate anthropometric data are available. In Western Europe and North America the increase in adult stature over the past century has commonly approximated one centimeter per decade, though with some variability between different groups. Other body dimensions, as well as weight, have also been increasing in both men and women and in different ethnic groups. The most likely explanations for such increases in body size are improved nutrition and better health care during growth years. Since such factors tend to be associated with higher socio-economic status, it is these groups who have demonstrated the most marked increases in body size in recent years. Many upper socio-economic groups have already attained most or all of their maximum body size potential, and will experience little further increase. On the other hand, those presently less favored groups who can still benefit from improved nutrition and health care will continue to show increases in body size until they also have reached their maximum potential.

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