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PubMed1981

A quantitative approach to the marsupial brain in an eco-ethological perspective.

Using a volumetric method and the classical allometry equation, the author investigates the possibility of a relationship between the size of total brain or brain-components and the ecology of ethology of 29 marsupials species from South-America and Australia. He shows that there is a relation between brain and neocortex volumes, and the taxonomic groups characterized by definite life-habits. New light is shed upon the evolution of marsupials showing that, while the living didelphids most probably are the closest to the ancestral type, some other groups such as the dasyurids and peramelids include even more primitive forms. This points to a very early separation of American and Australian marsupials and to a long independent evolution, perhaps dating back to immediately pre-marsupial times.

Animals↗
PubMed1981

[Comparison of the developing temporal neocortex with the sensorimotor cortex in rats (author's transl)].

The development of the cortical thickness, the length of apical dendrites and the total amount of apical dendrite spines of layer V pyramidal neurons in albino rat temporal and sensorimotor cortex in Golgi-Cox preparations is related to another during the first 3 postnatal months. The graphs demonstrate the relative growth of the features. The allometries are discussed in relation to general organizational processes during the postnatal rat ontogenesis (hearing, transition period with weaning and period of primary socialization according to Scott et al. 1974).

Animals↗
PubMed1981

[The effect of training and anabolic agents on the weight of the heart and extremities].

Albino-mice (50 animals per group) were exercised (running) for 30 days (29,6 km/animal totally) or received in the same period Methandrostenolon (0,12 mg/animal). With a third group exercise and anabolic steroid was combined. Mean body weight, mean weight of fore and hind leg, also mean weight of heart were compared between the groups and with corresponding weights of the control group. Calculating with allometry equation the influence of both exogen factors on weight of extremities and weight of heart was determined. Anabolic steroid resulted an increased body weight, significantly more than in the control animals. Exercise reduced statistically the weight of living animals. Without influence of body weight the combination of exercise and anabolic steroid made an increase to the weight of extremities, especially of the hind leg. The weight of heart increased only after exercise.

Animals↗
PubMed1980

[The brain of Gallus domesticus L., a quantitative analysis of embryonic and postnatal growth].

The study among domestic fowls (Gallus domesticus L.) of the growth allometry of various brain structures in comparison with the body weight during the embryonic and post natal period leads to two different conclusions: Every structure shows a growth alteration which occurs about hatching time and is characterized by an abrupt decrease of the slope of the reducted major axis. The comparison of the allometric characteristics of every structure with those of the entire brain allows to distinguish between three kinds of growth; regressive, steady or progressive. A slow and early growth is typical of a phylogenetically ancient structure; a dynamic and late growth shows a phylogenetically recent structure. This corroborates the corticoid trend among some striated complexes (Neostriatum, ventral Hyperstriatum) that several authors had thought of.

Animals↗
PubMed1980

[Comparative volumetric analysis of the principal subdivisions of the telencephalon in saurian reptiles].

The volumetric measure of the main subdivisions of the telencephalon has been carried on 24 species of Lizards and 2 species of Snakes. The studied structures are termed as follows: main and accessory olfactory bulbs, medial cortex (M 1 and M 2), dorsal cortex (D 1, D 2 and D 3), lateral cortex (L), Septum, Tuberculum olfactorium, dorsal and ventral striatum, amygdala and nucleus sphaericus. The analysis of the datas makes use of the SNEL L's formula which relates the volume of the various telencephalic subdivisions (V) to the somatic weight (S): V = k x S alpha. Each alpha value is compared to the value of the coefficient of allometry (A) of the whole brain. The evolutive (phylogenetic) growth of a structure is said fast (or slow) when its corresponding alpha value is higher (or lower) than the encephalic A value. At the cortical level such analysis shows the progressive nature of the dorsal cortex. A partition of the sample into Lacertomorpha (14 species) and Dracomorpha (10 species) (in agreement with the NORTHCUTT'S definition of his Type I and Type II Lizards) corroborates this cortical detail, more distinctly with the second group as well (especially for the D 2 portion). Moreover the high number of progressive structures among the Dracomorpha leads to consider this group as phylogenetically the most advanced in the Order of Lizards. The somatic indices are calculated according the allometric characteristics of the Reference Lizards. The judicious choice of some species allows to show how the development of a biological function may be expressed by the values of the indices of the related structures. For examples: dorsal cortex, dorsal striatum and mode of locomotion; olfactory bulbs, lateral cortex, part M 1 of the medial cortex and olfactory system; D 3 subdivision of the dorsal cortex and visual performances. The duality between Lacertomorpha and Dracomorpha is therefore corroborated by significant differences found for the various indices of a great number of telencephalic subdivisions. It leads moreover to find, grosso modo, two functional types of Lizards: moving-on-the-ground and wellsmelling (mainly Lacertomorpha) on the one hand, arboreal and with a fine vision (mainly Dracomorpha) on the other hand. The isoponderal percentages take an useful illustration of these results; it allows to establish the telencephalic pattern of a standard Lizard in which the pallium keeps the larger part (42%); in the pallium itself, the M 1 subdivision of the medial cortex has the most important percentage, a little more than the D 2 part of the dorsal cortex. A comparative study carried on 2 Snakes gives for Boa constrictor the lowest values of the indices, for almost all the structures. In return Natrix natrix stays, for a great number of structures, close to the level of the legless Lizards; this last result confirms distinctly the two levels of telencephalization already found in Snakes (PLATEL, 1976 a).

Amygdala↗
PubMed1995

Multivariate quantitative genetics of anthropometric traits from the Boas data.

The use of multivariate quantitative trait information to address questions of population relationships and evolutionary issues has a long-standing history in human anthropometry. Previous analyses have usually rested on a number of explicit or implicit assumptions that allow phenotypic information to be used as a proxy for quantitative genetic information. One (usually implicit) assumption is that the additive genetic variance-covariance matrix (G) among traits is proportional to the phenotypic variance-covariance matrix (P). In this study we discuss the implications of this assumption, demonstrating that if it is true that G = h2P, where h2 is some constant of proportionality, then (1) the biological (phenotypic) Mahalanobis distance will be proportional to genetic distance, (2) phenotypic and genetic allometry coefficients will be equal, and (3) evolutionary models will become simplified. We then use a multivariate quantitative genetic analysis of 12 anthropometric traits in 5 tribes to demonstrate that G = h2P for at least a portion of the Boas data.

Adult↗
PubMedDate not supplied

Craniofacial features in patients with deficient and excessive growth hormone.

We studied the role of growth hormone (GH) in craniofacial growth by analyzing the craniofacial structures in patients with either deficient or excessive GH. The cephalogrammes of 21 patients with isolated or combined GH deficiency and of two patients with GH excess were compared with cephalogrammes of age and sex matched controls, and the patients with deficient GH also with height and sex matched controls. In cephalometric measurements, skeletal anatomy was followed as closely as possible. All patients had a Class I or an end-to-end dental occlusion. Head circumference was normal in all patients. Facial widths were significantly smaller in patients with deficient GH but at the level of + 2 SDs in the two with GH excess when compared to Finnish norms. In patients with deficient GH, facial heights were significantly smaller than in age matched controls, but of the same order with height controls for anterior facial height. Posterior facial height was smaller even in this comparison. In patients with GH excess, facial heights were much larger and at the levels of +3 and +6 SD. Clivus was shorter in patients with deficient GH and longer (+ 1.9 and +3 SD) in the two with GH excess. All angulations of the sphenoidal plane deviated from those of the controls in the group with GH deficiency. The cranial base angle (CL-SPhen) was smaller than in controls while it was normal in patients with GH excess. We are inclined to interpret the craniofacial structure of those with deficient GH as being unique to the condition rather than merely negative allometry.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

Allometric comparison of brain and main brain subdivisions in birds.

The brain weights and volumes of the main brain subdivisions: telencephalon, diencephalon, mesencephalic tegmentum, optic tectum, cerebellum and myelencephalon were measured in 8 species of Phasianoidea (Galliformes) and in 20 species of birds belonging to 13 orders. The sizes of these structures were compared using allometry formulae calculated for each structure from the 8 Phasianoidea. Encephalization and the relative size of the main brain subdivisions are expressed by size indices. Higher encephalization indices are obtained in species which are either highly telencephalized as in Psittaciformes or with a large cerebellum as in Sphenisciformes. The brainstem components: diencephalon, mesencephalic tegmentum and myelencephalon appear to be more conservative in their size variation than the telencephalon, cerebellum and optic tectum. The size of the cerebellum appears to be related to flight abilities. The size of the optic tectum is related to the importance of vision in foraging within the Charadriiformes. In tactile-feeding Charadriiformes and filter-feeding Anseriformes, the optic tectum is relatively small.

Animals↗
PubMed1995

The weight of the heart in Callithrix Erxleben, 1777.

The allometric relationship between the weight of the heart and the body measurements was analyzed in 31 primates of genus Callithrix (C. jacchus and C. penicillata). The data were analyzed after logarithmic transformation using the model: Ln Y = Ln a + (b) Ln X. We compared with the t-test the slopes of the males and females and the slopes of the C. Jacchus and C. penicillata. Positive allometry was found to the weight of the heart in relation to the body weight (except to females of C. penicillata = isometry) and to sitting height in females of C. jacchus and males of C. penicillata. The relationship of the weight of the heart with the sitting height was isometric in males of C. jacchus and negative in females of C. penicillata. We cannot reject the null hypothesis analyzing the differences between the slopes of males and females. Therefore, in these two species of Callithrix we accept the concept of monomorphism.

Animals↗
PubMed1996

Multivariate morphometrics of larvae of the blacklegged tick (Ixodes scapularis) with notes on nomenclature.

A morphological study of the larval stage of the blacklegged tick, Ixodes scapularis, was conducted to further examine congruence between northern and southern morphotypes. Preliminary ANOVA revealed that 9 characters were not significantly different; thus 28 characters were used in analyses of a total of 8 groups of I. scapularis originally from Minnesota, Massachusetts, Maryland, Missouri, North Carolina, Georgia, F1 progeny of reciprocal crosses of ticks from Massachusetts and Georgia, and I. pacificus from California. Principal components (PC) analysis identified seven setal (sternal, preanal, 3 scutal, central, and marginal dorsal) and 3 nonsetal characters (interauricular distance, hypostome internal file, and coxa I internal spur) with positive static allometries. All Mahalanobis distances in canonical variate analyses (CVA) including and excluding I. pacificus and setal characters were significantly different. Scatterplots from PC and CVAs separated I. pacificus from all other groups in the first axis; the second function arranged groups in a pattern related to latitude. Unlike the results of previously reported nymphal analyses, no multivariate effect related to longitude was revealed; however, Missouri larvae had the shortest values for 2 setal and 9 nonsetal characters. As in nymphs, frequency polygons revealed an overlapping/continuous pattern, indicative of clinal geographic variation.

Analysis of Variance↗
PubMed1977

[Eco-ethological significance of the allometric development of the two visual systems in chiroptera].

Volumes of the rostral colliculus and the nuclei of the geniculate body were examined in 19 species of Chiroptera belonging to 8 families characterized by different eco-ethological adaptations. These volumes were compared to those of Basal Insectivores using the allometry formula. The data were expressed in terms of progression indices which estimate how many times a given brain center is greater than that of a Basal Insectivore of the same body weight. According to the progression indices of the rostral colliculus, Chiroptera separate into two groups: the Megachiroptera which have a mean index of 331 and the Microchiroptera with a mean index of 188. On the other hand, mean indices of the lateral geniculate body distinguish between three groups : the Megachiroptera (mean 869); the frugivorous and nectarivorous Microchiroptera (mean 293); the insect-eating, blood sucking, and fish eating Microchiroptera (mean 135). The results indicate that the two anatomically and structurally distinct elements belong to two functionally different visual systems which have evolved somewhat independently. The relation between allometric development of these visual centers and the eco-ethological adaptations of the species examined reveals, to a certain extent, the relative importance of the different functional aspects of vision.

Adaptation, Biological↗
PubMedDate not supplied

[Life cycle strategies: a synthesis of empirical and theoretical approaches].

A scheme of relationships among life-history characters is developed on assumptions of determinate growth and dependence of juvenile mortality on the specific growth rate. It is shown that constraints on the relative neonate size, (W0/W infinity), and minimum value of the biotic potential, (rmax), lead to "triangular" shape of life history set on the plain defined by juvenile and adult mortality. This completely coincides with the Ramenskiĭ++--Grime (C-S-R) classification of life-history strategies. Phylogenetic constraints can reduce this set to a relatively narŕow r/K-continuum specifically oriented for a certain taxon. Similar restrictions generate models of life history optimization which predict interspecific allometries between life-history traits.

Aging↗
PubMed2000

Using the Past to Predict the Present: Confidence Intervals for Regression Equations in Phylogenetic Comparative Methods.

Two phylogenetic comparative methods, independent contrasts and generalized least squares models, can be used to determine the statistical relationship between two or more traits. We show that the two approaches are functionally identical and that either can be used to make statistical inferences about values at internal nodes of a phylogenetic tree (hypothetical ancestors), to estimate relationships between characters, and to predict values for unmeasured species. Regression equations derived from independent contrasts can be placed back onto the original data space, including computation of both confidence intervals and prediction intervals for new observations. Predictions for unmeasured species (including extinct forms) can be made increasingly accurate and precise as the specificity of their placement on a phylogenetic tree increases, which can greatly increase statistical power to detect, for example, deviation of a single species from an allometric prediction. We reexamine published data for basal metabolic rates (BMR) of birds and show that conventional and phylogenetic allometric equations differ significantly. In new results, we show that, as compared with nonpasserines, passerines exhibit a lower rate of evolution in both body mass and mass-corrected BMR; passerines also have significantly smaller body masses than their sister clade. These differences may justify separate, clade-specific allometric equations for prediction of avian basal metabolic rates.

allometry↗