scholarly journals Can clade age alone explain the relationship between body size and diversity?

2012 ◽  
Vol 2 (2) ◽  
pp. 170-179 ◽  
Author(s):  
Rampal S. Etienne ◽  
Sara N. de Visser ◽  
Thijs Janzen ◽  
Jeanine L. Olsen ◽  
Han Olff ◽  
...  
Keyword(s):  
Body Size ◽  
Size Dependence ◽  
Allometric Scaling ◽  
The Body ◽  
Scaling Exponent ◽  
Extinction Rate ◽  
Extinction Rates ◽  
Constant Rate ◽  
Wide Range ◽  
Birth Death

One of the most striking patterns observed among animals is that smaller-bodied taxa are generally much more diverse than larger-bodied taxa. This observation seems to be explained by the mere fact that smaller-bodied taxa tend to have an older evolutionary origin and have therefore had more time to diversify. A few studies, based on the prevailing null model of diversification (i.e. the stochastic constant-rate birth–death model), have suggested that this is indeed the correct explanation, and body-size dependence of speciation and extinction rates does not play a role. However, there are several potential shortcomings to these studies: a suboptimal statistical procedure and a relatively narrow range of body sizes in the analysed data. Here, we present a more coherent statistical approach, maximizing the likelihood of the constant-rate birth–death model with allometric scaling of speciation and extinction rates, given data on extant diversity, clade age and average body size in each clade. We applied our method to a dataset compiled from the literature that includes a wide range of Metazoan taxa (range from midges to elephants). We find that the higher diversity among small animals is indeed, partly, caused by higher clade age. However, it is also partly caused by the body-size dependence of speciation and extinction rates. We find that both the speciation rate and extinction rate decrease with body size such that the net diversification rate is close to 0. Even more interestingly, the allometric scaling exponent of speciation and extinction rates is approximately −0.25, which implies that the per generation speciation and extinction rates are independent of body size. This suggests that the observed relationship between diversity and body size pattern can be explained by clade age alone, but only if clade age is measured in generations rather than years. Thus, we argue that the most parsimonious explanation for the observation that smaller-bodied taxa are more diverse is that their evolutionary clock ticks faster.

scholarly journals The body-size dependence of mutual interference

2014 ◽  
Vol 10 (6) ◽  
pp. 20140261 ◽  
Author(s):  
John P. DeLong
Keyword(s):  
Population Dynamics ◽  
Body Size ◽  
Size Dependence ◽  
Empirical Support ◽  
Mutual Interference ◽  
The Body ◽  
Wide Range ◽  
Stabilizing Effect ◽  
Body Sizes ◽  
Size Scales

The parameters that drive population dynamics typically show a relationship with body size. By contrast, there is no theoretical or empirical support for a body-size dependence of mutual interference, which links foraging rates to consumer density. Here, I develop a model to predict that interference may be positively or negatively related to body size depending on how resource body size scales with consumer body size. Over a wide range of body sizes, however, the model predicts that interference will be body-size independent. This prediction was supported by a new dataset on interference and consumer body size. The stabilizing effect of intermediate interference therefore appears to be roughly constant across size, while the effect of body size on population dynamics is mediated through other parameters.

scholarly journals Changes in body temperature influence the scaling of and aerobic scope in mammals

2006 ◽  
Vol 3 (1) ◽  
pp. 100-103 ◽  
Author(s):  
James F Gillooly ◽  
Andrew P Allen
Keyword(s):  
Body Size ◽  
Metabolic Rate ◽  
Size Dependence ◽  
Maximal Activity ◽  
Scaling Exponent ◽  
Temperature Influence ◽  
Aerobic Scope ◽  
Metabolic Scope ◽  
Single Power ◽  
Maximum Metabolic Rate

Debate on the mechanism(s) responsible for the scaling of metabolic rate with body size in mammals has focused on why the maximum metabolic rate ( ) appears to scale more steeply with body size than the basal metabolic rate (BMR). Consequently, metabolic scope, defined as /BMR, systematically increases with body size. These observations have led some to suggest that and BMR are controlled by fundamentally different processes, and to discount the generality of models that predict a single power-law scaling exponent for the size dependence of the metabolic rate. We present a model that predicts a steeper size dependence for than BMR based on the observation that changes in muscle temperature from rest to maximal activity are greater in larger mammals. Empirical data support the model's prediction. This model thus provides a potential theoretical and mechanistic link between BMR and .

scholarly journals Skull and buccal cavity allometry increase mass-specific engulfment capacity in fin whales

2009 ◽  
Vol 277 (1683) ◽  
pp. 861-868 ◽  
Author(s):  
Jeremy A. Goldbogen ◽  
Jean Potvin ◽  
Robert E. Shadwick
Keyword(s):  
Body Size ◽  
Foraging Ecology ◽  
The Body ◽  
Foraging Efficiency ◽  
Energetic Cost ◽  
Tail Region ◽  
Fin Whale ◽  
Wide Range ◽  
Fin Whales ◽  
Lunge Feeding

Rorqual whales (Balaenopteridae) represent not only some of the largest animals of all time, but also exhibit a wide range in intraspecific and interspecific body size. Balaenopterids are characterized by their extreme lunge-feeding behaviour, a dynamic process that involves the engulfment of a large volume of prey-laden water at a high energetic cost. To investigate the consequences of scale and morphology on lunge-feeding performance, we determined allometric equations for fin whale body dimensions and engulfment capacity. Our analysis demonstrates that larger fin whales have larger skulls and larger buccal cavities relative to body size. Together, these data suggest that engulfment volume is also allometric, increasing with body length as . The positive allometry of the skull is accompanied by negative allometry in the tail region. The relative shortening of the tail may represent a trade-off for investing all growth-related resources in the anterior region of the body. Although enhanced engulfment volume will increase foraging efficiency, the work (energy) required to accelerate the engulfed water mass during engulfment will be relatively higher in larger rorquals. If the mass-specific energetic cost of a lunge increases with body size, it will have major consequences for rorqual foraging ecology and evolution.

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.

METABOLIC RATE AND ITS TEMPERATURE-ADAPTIVE SIGNIFICANCE IN SIX GEOGRAPHIC RACES OF PEROMYSCUS

1965 ◽  
Vol 43 (2) ◽  
pp. 309-323 ◽  
Author(s):  
J. S. Hayward
Keyword(s):  
Body Weight ◽  
Body Size ◽  
Metabolic Rate ◽  
Single Equation ◽  
Adaptive Significance ◽  
The Body ◽  
Single Group ◽  
Critical Temperatures ◽  
Wide Range ◽  
Per Se

The metabolic rate characteristics of six races of Peromyscus, selected from a wide range of habitats, have been determined over the temperature range 0° to 35 °C. After acclimation to standardized laboratory conditions, critical temperatures and metabolic responses to temperatures below thermoneutrality were largely a function of body size: the larger the mouse, the greater its thermoregulatory efficiency. Body size per se is not correlated with the gross climate of the respective habitats. A single equation which predicts the metabolic rate of these races at any temperature between 0° and 27 °C, from a knowledge of body weight and body temperature, is derived.When considered as a single group, the basal oxygen consumption of all races varied with body weight0,60 over the body weight range of 14.7 to 36.0 g and was insignificantly different from the accepted interspecies approximation. The basal metabolic rates of each race showed no temperature-adaptive differences, especially when considered in relation to body composition. It is concluded that basal metabolic rate is nonadaptive to climate in these races of Peromyscus and consequently has played no important part in their distribution and speciation.

scholarly journals The Body Size Dependence of Trophic Cascades

2015 ◽  
Vol 185 (3) ◽  
pp. 354-366 ◽  
Author(s):  
John P. DeLong ◽  
Benjamin Gilbert ◽  
Jonathan B. Shurin ◽  
Van M. Savage ◽  
Brandon T. Barton ◽  
...  
Keyword(s):  
Body Size ◽  
Size Dependence ◽  
Trophic Cascades ◽  
The Body

Variations in the relationship between oxygen consumption, body size and summated tissue metabolism in the winkle Littorina littorea

1971 ◽  
Vol 51 (2) ◽  
pp. 315-338 ◽  
Author(s):  
R. C. Newell ◽  
V. I. Pye
Keyword(s):  
Body Weight ◽  
Body Size ◽  
Fractional Power ◽  
The Body ◽  
Acclimation Temperature ◽  
Large Mammals ◽  
Fundamental Relationship ◽  
Wide Range ◽  
Unicellular Organisms ◽  
The Relationship

INTRODUCTIONA considerable amount of data now exists on the relationship between metabolism and body size in a wide range of organisms from bacteria and protozoans through to large mammals. Much of this information has been reviewed by Kleiber (1932, 1947), Brody and Procter (1932), Brody (1945), Zeuthen (1947, 1953), Hemmingsen (1950, i960) and Bertalanffy (1957). In general the metabolism has been shown to be proportional to a fractional power of the body weight thus eggs, the larger metazoan poikilotherms and even homoiotherms is proportional to a constant power of the body weight. This factor has been shown to be 0.751 ± 0.015 by Hemmingsen (i960). Superimposed upon this general relationship are variations according to the weight range of the organisms concerned. Thus both Zeuthen (1953) and Hemmingsen (i960) have shown that the value of the constant b for unicellular organisms is approximately 0.7 (Zeuthen, 1953) or 0.751 (Hemmingsen, 1960), whilst that for small metazoans is 0.95 (Zeuthen, 1953) or 1.0 (Hemmingsen, 1960). Finally, the slope of the line relating the metabolism to body size in larger metazoans is 075 (Zeuthen, 1953) or 0.751 (Hemmingsen, 1960). That is, the value for b — 1 in equation (2) is likely to be between -0.3 and -0.249 in unicellular organisms; 0 and -0.05 in small metazoans and approximately -0.249 in larger metazoans.Despite this apparently fundamental relationship between metabolism and body size, there are many instances where for a particular species the relationship may not apply. Indeed in some species the metabolism may vary in its relationship to body weight according to conditions such as salinity, shore level, experimental temperature and acclimation temperature.

Body Size and the Growth of Maximal Aerobic Power in Children: A Longitudinal Analysis

1997 ◽  
Vol 9 (3) ◽  
pp. 262-274 ◽  
Author(s):  
Thomas Rowland ◽  
Paul Vanderburgh ◽  
Lee Cunningham
Keyword(s):  
Gender Differences ◽  
Body Size ◽  
Body Mass ◽  
Allometric Scaling ◽  
Aerobic Power ◽  
Maximal Aerobic Power ◽  
Scaling Exponent ◽  
Cross Sectional ◽  
Treadmill Testing ◽  
The Mean

Adjustment of VO2max for changes in body size is important in evaluating aerobic fitness in children. It is important, therefore, to understand the normal relationship between changes VO2max and body size during growth. Over the course of 5 years, 20 children (11 boys, 9 girls) underwent annual maximal treadmill testing to determine VO2max. The mean longitudinal allometric scaling exponent for VO2max relative to body mass (M) was 1.10 ± 0.30 in the boys and 0.78 ± 0.28 in the girls (p < .05). Respective cross-sectional values were 0.53 ± 0.08 and 0.65 ± 0.03. VO2max expressed relative to M1.0, M0.75, and M0.67 rose during the 5 years in the boys, but not the girls. Significant gender differences remained when VO2max was related to lean body mass. These findings suggest (a) factors other than body size affect the development of VO2max in children, and (b) gender differences exist in VO2max during childhood which are independent of body composition.

Allornetric Scaling of VO2 Max by Body Mass and Lean Body Mass in Older Men

1995 ◽  
Vol 3 (4) ◽  
pp. 324-331 ◽  
Author(s):  
Michael J. Davies ◽  
Gail P. Dalsky ◽  
Paul M. Vanderburgh
Keyword(s):  
Body Size ◽  
Lean Body Mass ◽  
Body Mass ◽  
Allometric Scaling ◽  
Older Men ◽  
Dual Energy ◽  
The Body ◽  
X Ray ◽  
Ratio Standards ◽  
Size Variable

This study employed allometry to scale maximal oxygen uptake (V̇O2max) by body mass (BM) and lean body mass (LBM) in healthy older men. Ratio standards (ml · kg−1· min−1) derived by dividing absolute V̇O2max (L · min−1) by BM or LBM often fail to control for the body size variable. The subjects were 73 older men (mean ±SD:age = 69.7 ± 4.3 yrs, BM = 80.2 ± 9.6 kg, height = 174.1 ± 6.9 cm). V̇O2max was assessed on a treadmill with the modified Balke protocol (V̇O2max = 2.2 ± 0.4 L · min−1). Body fat (27.7 ± 6.4%) was assessed with dual energy x-ray absorptiometry. Allometry applied to BM and V̇O2max determined the BM exponent to be 0.43, suggesting that heavier older men are being penalized when ratio standards are used. Allometric scaling applied to LBM revealed the LBM exponent to be 1.05 (not different from the ratio standard exponent of 1.0). These data suggest that the use of ratio standards to evaluate aerobic fitness in older men penalized fatter older men but not those with higher LBM.

A new method for estimating the morphometric size at maturity of crabs

1998 ◽  
Vol 55 (3) ◽  
pp. 704-714 ◽  
Author(s):  
George Watters ◽  
Alistair J Hobday
Keyword(s):  
Body Size ◽  
A Priori ◽  
Smoothing Splines ◽  
The Body ◽  
New Method ◽  
Second Derivative ◽  
Size At Maturity ◽  
Relative Growth ◽  
Wide Range ◽  
Body Sizes

Existing techniques for estimating the morphometric size at maturity of crabs are based on assumptions that may be unnecessary. Here we demonstrate a new method of detecting changes in relative growth (or allometric) relationships and estimating morphometric size at maturity. This method involves fitting several smoothing splines to relationships between body size and claw size, selecting the "best" spline, and finding this spline's maximum second derivative. The body size where the second derivative of the best spline is maximized estimates the morphometric size at maturity. Monte Carlo simulations suggest that uncertainty and bias in the estimate of morphometric size at maturity can be decreased by measuring a large number of crabs from a wide range of body sizes. Our spline method does not require a priori assumptions about the shape of the relative growth relationship; it can detect multiple changes in the relative growth rate; and it is robust to outliers. The modeling technique may also be used to identify regions of allometric change in other types of relationships. We demonstrate the new technique by estimating the morphometric size at sexual maturity for males of both brachyuran (Chionoecetes tanneri) and anomuran (Paralomis spinosissima and P. formosa) crabs.

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