Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Allometry”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 55 records · Page 3Linked to original sources
PubMed1981

On the definition of variables in studies of primate dental allometry.

Cranial and dental measurements are taken on 253 adult female primates from 32 species. Regression equations are calculated to determine allometric relationships between anterior tooth size, posterior tooth size, and body size. When cranial length or skull length is used as the measure of general size, the results of the equations differ from when body weight is the reference dimension. Similarly, using different definitions of posterior tooth size (such as mandibular second molar length and maxillary postcanine area) alters results substantially. The same occurs with different definitions of anterior tooth size. It has been common in studies of primate dental allometry to generalize from the specific variables measured to broad functional interpretations. However, highly correlated variables cannot be substituted one for another in allometric analyses without important changes in the results of the equation. Interpretation of allometric data is more highly restricted to the precise variables measured in a particular study than has been generally recognized.

Animals↗
PubMed1982

Allometry and adaptation in the catarrhine postcranial skeleton.

Seven measurements were taken on the postcranial skeleton of 249 specimens representing ten species of catarrhine primates and tested to determine their relationship with size. Size was measured as skeletal weight on each individual. It was found that the interspecific line based on the entire sample was in some cases determined not only by morphological adjustments for size variation but also by changes in locomotor adaptations of differently sized species within the sample. It is suggested that it is consequently preferable to study allometric relationships within a species or within a group of species that differ in size but are similar in their mode of locomotion. The allometric analysis reveals some interesting patterns within the data. Limb lengths scaled with either negative allometry or isometry over the entire sample. Within the species groups isometry was the rule except for pongid femurs, which showed negative scaling. Humerus length scaled at the same rate in pongids as in cercopithecoids but had a slightly higher intercept value. While colobines and cercopithecines scaled at similar rates for all seven dimensions, the colobine line was shifted to a position above that for cercopithecines in every case. It is suggested that this is a result of adaptation for leaping in the former group. Other implications of the allometric results are discussed.

Adaptation, Physiological↗
PubMed1983

The allometry of relative cusp size in hominoid mandibular molars.

The crown area (MCBA) and cusp areas of mandibular molars of Homo sapiens (M-1 = 131; M-2 = 71), Gorilla (M-1 = 25) and Pongo (M-1 = 24) were studied to determine whether the relative size of the mesial and distal cusps are related to overall crown size. Allometric trends were assessed by examining the correlation between relative cusp areas and MCBA and by calculating the slope of the regression line of log cusp area and log MCBA. With the exception of the metaconid in the Homo sapiens M-2S, the results of the intraspecific analyses provide little evidence of an allometric trend for relative reduction of the mesial cusps with increasing crown size. None of the samples provide consistent or reliable evidence of such a trend for the protoconid, nor do the M-1 samples provide evidence for such a trend for the metaconid. The evidence from the distal cusps is also mixed: positive allometry for the entoconid for the Homo sapiens M-2S and for the hypoconulid for the Homo sapiens M-1S, with no departure from isometry in either Gorilla or Pongo. The interspecific data provide no evidence of any trend for the mesial cusps to decrease or the distal cusps to increase in importance in larger teeth. If one accepts the proposition that the static allometric trends observed in this study are reasonable analogues for any allometric relationships within, or between, fossil hominid taxa, then the evidence presented above does not support the hypothesis that the reduction of the trigonid, which is observed in the "robust" australopithecines, is an allometric phenomenon.

Adult↗
PubMed1986

Ecological significance of hypometabolism in nonhuman primates: allometry, adaptation, and deviant diets.

The "Kleiber relationship" describes the interspecific allometry between body size and metabolism. Like other allometric relationships, the Kleiber relationship not only summarizes scaling effects across species but also provides a standard by which species can be compared. One well-noted deviation from the Kleiber relationship is "hypometabolism": metabolic rates below that expected for a given size. It has been suggested in the literature that hypometabolism may be a primitive mammalian trait, a thermoregulatory adaptation, an adaptation to arboreal folivory, or an adaptation to a diet that is deviant for body size. Data on primate physiology and behavior are used to evaluate these hypotheses. Only the deviant-diet hypothesis is supported by the data on nonhuman primates. Indeed, the Jarman-Bell relationship, which is the basis for this hypothesis, provides a more coherent explanation of correlated features of animal physiology and behavior than do the alternative models. Hypometabolism may be an energy-conserving adaptation to a variety of nutritional stresses. The present analysis underscores the point that metabolic rate, like foraging behavior, should be thought of as evolutionarily labile.

Adaptation, Physiological↗
PubMed1987

Allometry of the limb long bones of insectivores and rodents.

In an attempt to investigate the relationships between allometry and locomotory adaptations, we studied the long limb bones of 45 species of insectivores and rodents. Animals ranged from a few grams to about 50 kilograms. Diameter and length of the bones and body mass (when known) were recorded. Regressions of diameter to length, diameter to body mass, and length to body mass were calculated by the least-squares and Model II, or major axis, methods. The results obtained do not agree with the predictions of either the theory of geometric similarity or the theory of elastic similarity. The discrepancies could be due to the fact that animals studied exhibit various modes of locomotion. Moreover, the allometric relationships of the different locomotor patterns are better reflected in insectivores and rodents than in other groups of mammals. The use of a single regression analysis seems to be inadequate when the sample includes a large range of body sizes.

Animals↗
PubMed1988

Allometry of the perivascular spaces of the putamen in aging.

The equation of simple allometry was used to study the relative growths of the diameters of the perivascular spaces (PSs), the diameters of the arterial vessels and their wall thicknesses in specimens of the putamen from 24 subjects aged 62 to 90 years. Our findings supported the view that the diameters of the PSs were mainly related to the dimensions of their arteries, especially in the elderly, and that they grew isometrically with arterial diameters. In addition, the diameters of the PSs were basically independent of age.

Aged↗
PubMed1987

Relative growth of adenomatous polyps of the colon. Stereology and allometry of multiple polyposis.

The volume of the adenomatous mucosa (V), the area of the surface epithelium (Ss), the area of the glandular epithelium (Sg), and the Sg: Ss ratio were calculated in a series of 14 adenomatous polyps (APs) of a case of multiple polyposis of the colon. The equation of simple allometry was used to study the relative growth of the four series of values. Ss grew isometrically with size; Sg overgrew Ss and accounted for most of the increase in V. The Sg:Ss ratio increased with Sg and V.

Colonic Polyps↗
PubMed1996

Ventilatory and metabolic responses of a bat, Phyllostomus discolor, to hypoxia and CO2: implications for the allometry of respiratory control.

The ventilatory and metabolic responses of lesser spear-nosed bats to hypoxia and hypercapnia were measured to determine whether these corresponded to preliminary allometries and a positive relationship between hypoxic ventilatory threshold and P50. Ventilatory responses of lesser spear-nosed bats to 3, 5 and 7% CO2 differed significantly from ventilation on air and each other. The magnitude of their ventilatory response to CO2 is consistent with the prediction of a smaller ventilatory response to hypercapnia in small compared to large mammals [% delta V varies MB0.130; Williams et al. (1994)]. Among 12, 10 and 8% O2 treatments only the ventilatory response to 8% O2 differed significantly from ventilation on air or the other treatments. Metabolic rate was significantly reduced at both 10 and 8% O2. The hypoxic ventilatory response of these bats does not support the prediction of a greater response in small compared to large mammals [% delta V veries MB0.273; Boggs and Tenney (1984)]. Their metabolic response is consistent with the hypoxic hypometabolism typical of small mammals, though not of comparable magnitude. The response, expressed as percent change in convection requirement (V/VO2), is also less than that observed in other small mammals. This relative insensitivity to hypoxia may be associated with this bat's unusually high affinity hemoglobin (P50 = 27.5 torr).

Anaerobiosis↗
PubMed1984

Growth and allometry in primate masticatory muscles.

A study of the dry weight of primate and non-primate masticatory musculature permitted possible allometric and ontogenetic influences on this musculature to be explored. Using weight as an indicator of adult body size, all of the masticatory muscles examined (anterior temporalis, posterior temporalis, masseter, medial pterygoid, lateral pterygoid, digastrics, and total adductor mass) are isometric. This is true even when prosimians and non-primates are removed from consideration, leaving only adult anthropoid primates. Thus, size-related changes do not affect the masticatory musculature of anthropoids differently from the musculature of examined prosimians and non-primates. However, other measures of body size (skull length, head and body length) reveal a different picture. Yet, irrespective of the indicator of body size chosen, the allometric properties of the masticatory muscles appear similar and the fluctuations of the various muscle indices therefore reflect functional changes, and are not caused by allometry. Exudate-eating and frugivory are discussed in relation to body size and the development of the mandibular depressor muscles. The logs of the masticatory muscles do not show a significant correlation with age, except when species are followed across age grades. For the five anthropoid species for which this is possible, the medial and lateral pterygoid and digastric muscles are still not correlated with age. When all examined species are considered, some muscle ratios correlate significantly with age. Following anthropoid species across age grades singles out an early surge in growth of the medial pterygoid muscle over the masseter muscle, a situation which was apparent also in the general age correlation.

Age Factors↗
PubMed1985

Basal metabolic rates in mammals: taxonomic differences in the allometry of BMR and body mass.

No single equation adequately describes the allometric relation between body mass and BMR for mammals. Least squares regression of log-transformed data for 248 eutherian species results in a line with a slope (-0.30) significantly different from that of Kleiber's line (-0.25). Interordinal comparisons of least squares regressions of log-transformed BMR and mass suggest that the Insectivora have a significantly steeper slope to their allometric relationship than do most other orders, while the non-insectivore orders are statistically homogeneous with respect to slope. With respect to elevation, Edentata have the lowest BMRs; Marsupialia, Primates and Chiroptera are indistinguishable from each other but above the edentates; Primates, Chiroptera, Rodentia, Lagomorpha and Carnivora form the next highest homogeneous grouping; and Artiodactyla have the highest BMRs, significantly greater than all but Lagomorpha and Carnivora. Analysis of intraordinal variation within the Rodentia suggests significant heterogeneity among families in BMR-mass allometry.

Animals↗
PubMed1989

Allometry of resting metabolic rate in cockroaches.

1. Resting VO2 at 22.7 degrees C was 0.217 +/- 0.007 ml O2/g/hr in Nauphoeta cinerea of 0.51 +/- 0.008 g body mass. 2. Whole animal resting metabolic rate for 11 cockroach species scaled allometrically: VO2 = 0.261 M0.776. 3. Allometry of resting VO2 among cockroach species is similar to that in vertebrates, and is consistent with models based on both "elastic similarity" and "biological similitude."

Animals↗
PubMed1988

On the time allometry of co-ordinated rhythmic movements.

The focus is the power formulae relating periodic time in terrestrial locomotion and flight to mass and length. The periodic timing of limbs and wings oscillating comfortably in absolute co-ordination is viewed as the characteristic period tau 0 of a system in which the free, undamped oscillatory motion of a point mass m at a distance l from a fixed axis does work against two conservative forces. These forces are in the form of gravity g acting on the point mass and a spring of stiffness k acting at a distance b from the axis. The system's characteristic period can be expressed most simply as: tau 0 = 2 pi [ml2/(mlg + kb2)]1/2. In the biological instantiation of this hybrid mass-spring/simple pendulum system, muscular and other tissues function as the spring that elastically stores and releases mechanical energy. Regular oscillations are brought about and sustained by a muscular driving force that ordinarily is close to resonance. The resultant dynamical regime--basically, raising and lowering a mass at regular intervals with respect to gravity--is referred to as the pendular clocking mode of movement organization. The mode is investigated comfortably at a common period and a fixed phase. In absolute co-ordination, two wrist-pendulum systems can be interpreted physically as a virtual single system. The evidence suggests that the scalings of the periodic times of such systems to mass and to length follow directly from the dynamical properties inherent in the resonance equation of the pendular clocking mode. Recourse to biological constants to rationalize the time scale is unnecessary. Experiments on human wrist-pendular activity and detailed analyses of the mass and length dependencies of the locomotory cycle times of quadrupeds, large birds, small passerines, hummingbirds, and insects are performed with respect to the dynamical properties predicted for systems in the pendular clocking mode. The major conclusion is that all the time scales of terrestrial in locomotory time allometries follow systematically from differences in the length scale and differences in the relation of mass to length.

Animals↗
PubMed1999

Allometry in vestibular responses of anurans.

Frogs and toads turn either their heads or bodies opposite to angular accelerations applied around the yaw axis. Thresholds exist for the minimum angular acceleration that induces this vestibulomotor response in individual frogs. These thresholds were recorded for several anuran species that cover a broad range of sizes and life styles. Interspecific variation in the magnitude of the thresholds, which correlated with the ecology and behavior of the species, was documented. Also an allometric relationship was observed between this threshold and body size; the larger the frog, the lower the threshold. In many species, the threshold value for reflexive vestibulomotor responses to angular acceleration was proportional to the -0.4 (+/-0.2) power of body mass. Physical dimensions of the semicircular canals determine, in part, vestibular sensitivity to angular acceleration. Hence changes with growth in the semicircular canals are believed to contribute to the slope of -0.4. The biological significance of this allometry in vestibular responses is discussed and compared to trends in vestibular sensitivity and semicircular canal morphology of other vertebrate classes.

Acceleration↗
PubMed1992

The ontogenesis of skin and organ characteristics in the Syrian golden hamster. III. Ontogenetic and intraspecific allometry for strain and sex as well as body weight- and age-dependent correlations.

The allometric relations, i.e. bodily characteristics, body weight-relationships as well as age-dependent organ and biochemical data were studied in a total of 464 golden hamsters of both sexes of an acromelanic white inbred and agouti coloured outbred strain. In the 3 age sections studied (I = day 1-20, II = day 25-100, III = day 110-365) the body weight- and age-dependent relations were found to be altered between and within the various characteristics. The body weight correlations predominated in the case of organ weights and skin muscle thickness. By contrast, age correlations were seen above all in the skin compartments with cyclic growth, hair follicle density and reticular thickness in the age sections I and II. Papillary thickness showed a positive relation to body weight and age after weaning, but no long-term relations were observed with both plasma insulin and blood glucose levels. The allometric behaviour of skin compartments could be explained particularly by thermoregulatory and "geometric" similarities and that of the organs by metabolic and other similarities. Most sex and strain differences in the absolute data, except for the kidney and adrenal weights, disappeared on allometric analysis and were thus mainly due to differences in body weight. For long-term toxicological investigations, the documentation of age and body weight as well as the determination of ontogenetic allometry is a "must".

Adrenal Glands↗
PubMed1992

Growth, development and allometry of Philophthalmus nocturnus in the eyes of domestic chicks.

Fifty day-old chicks were each infected with 10 excysted metacercariae of Philophthalmus nocturnus Looss, 1907 around each orbit and growth, development and allometry were studied. The growth rate showed two phases over a period of 35 days, a limited lag phase lasting two days post-infection in which flukes did not exceed 440 microns in length, and a rapid phase during which growth was rapid and flukes reached a size of 3.008-3.504 mm on day 35. Five developmental stages were noticed during the course of development of the metacercaria to the egg-producing adult stage. Eggs appeared in the uterus on day 14 and oculate miracidia on day 25. The hindbody, testes and ovary showed positive allometric growth, the pharnyx less so, whereas negative allometric growth was shown by the forebody. Body width, oral sucker and ventral sucker were close to isometry, growing at the same rate as the body length.

Animals↗
PubMed1979

Primate facial allometry and interpretations of australopithecine variation.

Pilbeam and Gould have discussed African Plio-Pleistocene hominid evolution in the context of allometry (size-dependent morphological change). These authors demonstrate that some general aspects of australopithecine morphology (tooth, brain and body size) support the hypothesis that certain early African hominids were merely scaled variations of each other at different sizes. They also speculate that the methods applied to these very broad anatomical categories can be extended to more specific and detailed traits, especially in the face and cranium. Such traits underlie most taxonomic and phylogenetic discussions of the early African Hominidae, so it is useful to follow Pilbeam and Gould's lead, as we do here, and investigate the structural differences in the australopithecine face and cranimum in a quantificiable fashion.

Africa↗
PubMed1999

Allometry of the cranial base in prepubertal Korean subjects with class III malocclusions: finite element morphometry.

Sphenoethmoidal allometry could be associated with ethnic heterogeneity of the midfacial profile. Thirteen cranial base landmarks were digitized from cephalographs of 69 Korean and 73 European American prepubertal children exhibiting Class III malocclusion. Average geometries were normalized, and a color-coded finite element (FEM) program was used to localize differences in morphology. ANOVA indicated that mean Korean and European American cranial base configurations differed statistically (p < 0.01); this was also true for seven age groups tested (p < 0.001). For size-change, FEM analysis revealed that in the anterior cranial base, Korean sphenoethmoidal and sella turcica regions were smaller (=12%). Local increases in size were apparent for the posterior region of the Korean cranial base (=35%). For shape-change, Korean and European American cranial base configurations were isotropic with minor anisotropy in the sphenoethmoidal and spheno-occipital regions. A sphenoethmoidal mechanism of midfacial retrognathism appears to be implicated in the development of a skeletal Class III morphology.

Analysis of Variance↗
PubMedDate not supplied

Longitudinal study of ontogenetic allometry of oxygen uptake in boys and girls grouped by maturity status.

The utility of removing the confounding effect of body mass on oxygen uptake by simply dividing the measured values by mass has been questioned: Allometric transformation or calculation of covariance analysis have been proposed as more appropriate alternatives. This study hypothesized that scaling factors for individual youths differ with maturity status. Peak oxygen uptake (peak VO2) during exercise on a bicycle ergometer, stature and body mass were measured at annual intervals in 47 active boys and 31 active girls from 11 to 14 years of age. All subjects attended sport schools during the study. The children were classified into two maturity categories, early and average (for the sake of sample size and consistency between sexes), and late on the basis of individual stature velocities in boys and age at menarche in girls. Individual data for peak VO2 were normalized for differences in body mass by double logarithmic transformation and regression analysis (ontogenetic allometry). Individual allometric coefficients (mean +/- SD) for boys showing a good fit were, respectively, 0.799 +/- 0.239 and 0.536 +/- 0.141 in early and average maturing boys combined and in late maturing boys. Logarithmic transforms of VO2 and mass were highly related (r > 0.90) in 10 of 16 early and average maturers, and in 18 of 31 late maturers. Corresponding individual allometric coefficients in girls were more variable, and the logarithmic transforms of VO2 and mass were not highly related (r < 0.70). Similar results were obtained for the relationships between the logarithmic transforms of VO2 and stature. The evidence thus suggests that in boys scaling VO2 for body mass varies with maturity status of the individual, and that there is considerable inter-individual variation in scaling coefficients during early and mid-adolescence. The increase in peak VO2 in active girls 11-14 years is not related to the increase in body mass or stature in the majority.

Adolescent↗