Search results for "Dimorphism"
showing 9 items of 169 documents
Dualistisches Fortpflanzungsverhalten bei dem protogynen LippfischThalassoma bifasciatum und einige Beobachtungen über dessen Tag-Nacht-Wechsel
1973
1.Thalassoma bifasciatum is a protogynous wrasse with (partial) sexual dimorphism and male dichromatism. Sex-inversion takes place without affecting the color pattern. 2. Males with female-like color dress indulge in group spawning; males with the bright color pattern perform pair spawning. 3. Among the brightly colored males exists a well-established hierarchy. Dominant males only have a particular spawning area in which they spawn daily at a certain time around noon. The spawning area is optically marked by conspicuous behavior of the bright male. Courtship activities towards individual partners are rather superficial. 4. The female has the leading role in pair spawning. In the extremely …
Sex-specific reaction of liver ultrastructure in zebra fish (Brachydanio rerio) after prolonged sublethal exposure to 4-nitrophenol
1989
Abstract Morphological alterations of the liver of zebra fish ( Brachydanio rerio ) following prolonged exposure to 0.1, 1 and 5 mg · l −1 4-nitrophenol (4-NP) were investigated by means of light and electron microscopy. Based on marked sexual dimorphism in control animals, liver recactions were both sex- and dose-dependent. Whereas at 0.1 mg·1 −1 only minor changes could be revealed, there were numerous structural modifications at 1 mg·1 −1 : Whereas male fish primarily react with a proliferation of smooth endoplasmic reticulum, female fish display a high degree of fenetrastion within cisternate of the rough endoplasmic reticulum. Both sexes exhibit infiltration of macrophages and lymphocy…
Microvascular Sex- and Age- Dependent Phosphodiesterase Expression
2021
Objective: The cyclic nucleotide second messengers, cAMP and cGMP, are pivotal regulators of vascular functions; their cellular levels are tightly controlled by the cyclic nucleotide hydrolases, phosphodiesterases (PDE). Biologic sex and age are recognized as independent factors impacting the mechanisms mediating both vascular health and dysfunction. This study focused on microvessels isolated from male and female rats before (juvenile) and after (adult) sexual maturity under resting conditions. We tested the hypothesis that sexual dimorphism in microvascular PDE expression would be absent in juvenile rats, but would manifest in adult rats.Methods: Abdominal skeletal muscle arterioles and v…
Sexual dimorphism in the vertebral wedging of the human lumbar vertebrae and its importance as a comparative framework for understanding the wedging …
2020
Lumbar lordosis is a key element of the upright posture, being interpreted as a consequence of bipedal locomotion. There is consensus that the generic modern human pattern of metameric vertebral body wedging is sexually dimorphic in modern humans. However, recently published studies have compared this pattern with other hominins, such as Neanderthals. These tried to establish whether the (male) Neanderthal lumbar vertebrae express a pattern that falls within or outside the range of modern human males. In the present study, data collected by 3D landmarks of the lumbar vertebrae of modern humans from different geographic regions and Neanderthals (Ntotal = 505 individual vertebrae) are used to…
Patterns of trunk spine growth in two congeneric species of acanthocephalan: investment in attachment may differ between sexes and species.
2012
SUMMARYAcanthocephalans have evolved a hooked proboscis and some taxa have trunk spines to attach to their definitive hosts. These structures are generated before being used, thus a key question is how investment in attachment could optimally be allocated through the ontogeny. The number and arrangement of hooks and spines are never modified in the definitive host, but it is unclear whether these structures grow during adult development. A comparison of the size of trunk spines between cystacanths and adults of Corynosoma cetaceum and C. australe indicated that spines grow in both species, but only in females, which also had significantly larger spines than males. This sexual dimorphism did…
Les Pseudoperisphinctinae (Ammonitina, Perisphinctidae) de l'horizon à Leckenbyi (Callovien supérieur, zone à Athleta) de Montreuil-Bellay (Maine-et-…
2008
International audience; Dans la région de Montreuil-Bellay (Maine-et-Loire), de nombreuses coupes ont été réalisées au passage Callovien moyen-Callovien supérieur. Le premier banc attribué au Callovien supérieur a été daté de l'horizon à Leckenbyi. Il a fourni une très importante faune ammonitique (N=3125), dans laquelle les Perisphinctidae représentent 51% de l'effectif. À côté de formes plus ou moins bien connues comme Pseudopeltoceras leckenbyi (Bean), Orionoides pseudorion (Waagen), Subgrossouvria famulum (Bean) et S. crassa Gérard et Contaut, on trouve une espèce qui n'a jamais été ni décrite ni figurée : cette espèce fait l'objet du présent article. Choffatia isabellae n. sp. se disti…
Sex Differences in the Physiological Network of Healthy Young Subjects
2021
Within human physiology, systemic interactions couple physiological variables to maintain homeostasis. These interactions change according to health status and are modified by factors such as age and sex. For several physiological processes, sex-based distinctions in normal physiology are present and defined in isolation. However, new methodologies are indispensable to analyze system-wide properties and interactions with the objective of exploring differences between sexes. Here we propose a new method to construct complex inferential networks from a normalization using the clinical criteria for health of physiological variables, and the correlations between anthropometric and blood tests b…
Sexes in gynodioecious Geranium sylvaticum do not differ in their isotopic signature or photosynthetic capacity
2017
In gynodioecious plants, females are expected to produce more or better seeds than hermaphrodites in order to be maintained within the same population. Even though rarely measured, higher seed production can be achieved through differences in physiology. In this work, we measured sexual dimorphism in several physiological traits in the gynodioecious plant Geranium sylvaticum. Photosynthetic rate, stomatal conductance, transpiration rate, WUE and isotopic signatures were measured in plants growing in two habitats differing in light availability. Females have been reported to produce more seeds than hermaphrodites. However, we did not observe any significant difference in seed output between …
Morphological variation of the unionidae mussel Anodonta anatina
2013
ABSTRACT Morphology of a given species can vary among individuals, morphology differences can be found between populations males can be different from females (sexual dimorphism) or e.g. with young and old individuals. The aim of the present study was to investigate morphological variability in the unionidae mussel Anodonta anatina originating from two populations. Measured variables included length, height, width, volume and dry mass of shell, dry mass of soft tissues and gill blades, and age, sex, estimation of glochidium larvae produced. The main results included faster growth of mussels in Lake Koijärvi than in Lake Päijänne (at the age of 4-5 years), which may reflect the higher produc…