scholarly journals Spawning, copulation and inbreeding coefficients in marine invertebrates

2005 ◽  
Vol 1 (4) ◽  
pp. 450-453 ◽  
Author(s):  
J.A Addison ◽  
M.W Hart
Keyword(s):  
Life History ◽  
Life Histories ◽  
Marine Invertebrates ◽  
Marine Invertebrate ◽  
Breeding Systems ◽  
Dispersal Ability ◽  
Inbreeding Coefficients ◽  
Enormous Variation ◽  
Population Genetic Variation ◽  
Analytical Approaches

Patterns of population genetic variation have frequently been understood as consequences of life history covariates such as dispersal ability and breeding systems (e.g. selfing). For example, marine invertebrates show enormous variation in life history traits that are correlated with the extent of gene flow between populations and the magnitude of differentiation among populations at neutral genetic markers ( F ST ). Here we document an unexpected correlation between marine invertebrate life histories and deviation from Hardy–Weinberg equilibrium (non-zero values of F IS , the inbreeding coefficient). F IS values were significantly higher in studies of species with free-spawned planktonic sperm than in studies of species that copulate or have some form of direct sperm transfer to females or benthic egg masses. This result was robust to several different analytical approaches. We note several mechanisms that might contribute to this pattern, and appeal for more studies and ideas that might help to explain our observations.

scholarly journals Life histories and the evolution of cooperative breeding in mammals

2012 ◽  
Vol 279 (1744) ◽  
pp. 4065-4070 ◽  
Author(s):  
Dieter Lukas ◽  
Tim Clutton-Brock
Keyword(s):  
Life History ◽  
Cooperative Breeding ◽  
Life Histories ◽  
Mating Systems ◽  
Reproductive Output ◽  
Breeding Systems ◽  
Life History Parameters ◽  
Socially Monogamous ◽  
Group Members

While the evolution of cooperative breeding systems (where non-breeding helpers participate in rearing young produced by dominant females) has been restricted to lineages with socially monogamous mating systems where coefficients of relatedness between group members are usually high, not all monogamous lineages have produced species with cooperative breeding systems, suggesting that other factors constrain the evolution of cooperative breeding. Previous studies have suggested that life-history parameters, including longevity, may constrain the evolution of cooperative breeding. Here, we show that transitions to cooperative breeding across the mammalian phylogeny have been restricted to lineages where females produce multiple offspring per birth. We find no support for effects of longevity or of other life-history parameters. We suggest that the evolution of cooperative breeding has been restricted to monogamous lineages where helpers have the potential to increase the reproductive output of breeders.

scholarly journals Asexual Reproduction of Marine Invertebrate Embryos and Larvae

2018 ◽  
Keyword(s):  
Asexual Reproduction ◽  
Life Histories ◽  
Developmental Plasticity ◽  
Developmental Stages ◽  
Marine Invertebrates ◽  
Marine Invertebrate ◽  
Taxonomic Diversity ◽  
Future Research ◽  
Open Questions ◽  
Juvenile Stages

Developmental plasticity during the early life histories of marine invertebrates is a fascinating opportunity to study the interplay between ecology and evolution. In particular, some embryos and larvae initiate asexual reproduction while completing their development. This chapter examines the mode, frequency, and taxonomic diversity of asexual reproduction that occurs between the zygotic and the juvenile stages. Special attention is given to the phylum Echinodermata, where asexual reproduction during embryonic and larval development has been best studied. An emphasis is also placed on the factors that have been identified as likely inducers of asexual reproduction and an assessment of the likelihood that asexual reproduction is an adaptive response to these factors. Lastly, several key open questions are identified as potential avenues for future research about the causes and consequences of asexual reproduction by the developmental stages of marine invertebrates.

Invasion success of a habitat-forming marine invertebrate is limited by lower-than-expected dispersal ability

2015 ◽  
Vol 536 ◽  
pp. 221-227 ◽  
Author(s):  
PR Teske ◽  
J Sandoval-Castillo ◽  
M Sasaki ◽  
LB Beheregaray
Keyword(s):  
Marine Invertebrate ◽  
Invasion Success ◽  
Dispersal Ability

Hormones and Behavior

2019 ◽  
pp. 11-26
Author(s):  
Maren N. Vitousek ◽  
Laura A. Schoenle
Keyword(s):  
Life History ◽  
Life Histories ◽  
Life History Traits ◽  
Developmental Plasticity ◽  
Endocrine System ◽  
Phenotypic Traits ◽  
Social Environments ◽  
Trade Offs ◽  
And Behavior

Hormones mediate the expression of life history traits—phenotypic traits that contribute to lifetime fitness (i.e., reproductive timing, growth rate, number and size of offspring). The endocrine system shapes phenotype by organizing tissues during developmental periods and by activating changes in behavior, physiology, and morphology in response to varying physical and social environments. Because hormones can simultaneously regulate many traits (hormonal pleiotropy), they are important mediators of life history trade-offs among growth, reproduction, and survival. This chapter reviews the role of hormones in shaping life histories with an emphasis on developmental plasticity and reversible flexibility in endocrine and life history traits. It also discusses the advantages of studying hormone–behavior interactions from an evolutionary perspective. Recent research in evolutionary endocrinology has provided insight into the heritability of endocrine traits, how selection on hormone systems may influence the evolution of life histories, and the role of hormonal pleiotropy in driving or constraining evolution.

scholarly journals Neurotoxicity in Marine Invertebrates: An Update

Biology ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 161
Author(s):  
Irene Deidda ◽  
Roberta Russo ◽  
Rosa Bonaventura ◽  
Caterina Costa ◽  
Francesca Zito ◽  
...  
Keyword(s):  
Nervous System ◽  
Marine Invertebrates ◽  
Marine Pollution ◽  
Marine Invertebrate ◽  
High Sensitivity ◽  
Model Systems ◽  
Neural Genes ◽  
Chemical Agents ◽  
Neurotoxic Effects ◽  
Invertebrate Model

Invertebrates represent about 95% of existing species, and most of them belong to aquatic ecosystems. Marine invertebrates are found at intermediate levels of the food chain and, therefore, they play a central role in the biodiversity of ecosystems. Furthermore, these organisms have a short life cycle, easy laboratory manipulation, and high sensitivity to marine pollution and, therefore, they are considered to be optimal bioindicators for assessing detrimental chemical agents that are related to the marine environment and with potential toxicity to human health, including neurotoxicity. In general, albeit simple, the nervous system of marine invertebrates is composed of neuronal and glial cells, and it exhibits biochemical and functional similarities with the vertebrate nervous system, including humans. In recent decades, new genetic and transcriptomic technologies have made the identification of many neural genes and transcription factors homologous to those in humans possible. Neuroinflammation, oxidative stress, and altered levels of neurotransmitters are some of the aspects of neurotoxic effects that can also occur in marine invertebrate organisms. The purpose of this review is to provide an overview of major marine pollutants, such as heavy metals, pesticides, and micro and nano-plastics, with a focus on their neurotoxic effects in marine invertebrate organisms. This review could be a stimulus to bio-research towards the use of invertebrate model systems other than traditional, ethically questionable, time-consuming, and highly expensive mammalian models.

scholarly journals Classical soloists’ life histories and the music conservatoire

2021 ◽  
pp. 025576142199115
Author(s):  
Tim Palmer ◽  
David Baker
Keyword(s):  
Higher Education ◽  
Life History ◽  
Life Histories ◽  
Qualitative Data ◽  
Classical Music ◽  
Loss Of Autonomy ◽  
Cultural Interest ◽  
Concert Pianist ◽  
Analytic Induction ◽  
Musical Excellence

This article explores the life histories of virtuoso classical music soloists with particular reference to conservatoire provision. Detailed life-history interviews were conducted with six virtuosi between May 2018 and January 2019. These participants were three singers, two cellists and a concert pianist. Resultant qualitative data were stored in an NVivo software database and understood through a process of analytic induction. Key findings spotlight the significance of Higher Education, a connection between broad creative and cultural interest and musical excellence, and a significant role for conservatoires in diversifying their training and easing transition into the career. The soloists also warned of dangers relating to controlling teachers, loss of autonomy and a need to convey their career realities to students.

Inadvertent Exemplars: Life History Portraits of Two Socially Just Principals

2012 ◽  
Vol 22 (1) ◽  
pp. 79-115 ◽  
Author(s):  
Martin Scanlan
Keyword(s):  
Social Justice ◽  
Life History ◽  
Elementary Schools ◽  
Middle Class ◽  
Life Histories ◽  
Public Elementary Schools ◽  
White Middle Class ◽  
English Speaking ◽  
Native English Speaking

This study creates life history portraits of two White middle-class native-English-speaking principals demonstrating commitments to social justice in their work in public elementary schools serving disproportionately high populations of students who are marginalized by poverty, race, and linguistic heritage. Through self-reported life histories of these principals, I create portraits that illustrate how these practitioners draw motivation, commitment, and sustenance in varied, complicated, and at times contradictory ways.

A comparative study of the life histories of Nematodirus battus and N. filicollis, nematode parasites of sheep

Parasitology ◽  
1959 ◽  
Vol 49 (3-4) ◽  
pp. 374-386 ◽  
Author(s):  
R. J. Thomas
Keyword(s):  
Life History ◽  
Intestinal Mucosa ◽  
Related Species ◽  
Life Histories ◽  
Basic Pattern ◽  
Culture Methods ◽  
Closely Related Species ◽  
Nematode Parasites ◽  
History Of ◽  
Comparative Description

1. The life history of N. battus is described, and a comparative description of the life history of N. filicollis is given.2. The life histories of these two species are compared with those of N. spathiger and N. helvetianus, two closely related species, and are shown to follow the same basic pattern, with minor variations in timing which appear to be specific in nature, and not related to differences in culture methods or host species.3. The pathogenesis of Nematodirus species is discussed and related to the migration of larvae into the intestinal mucosa during development.

On the Chemical Form of Mercury in Edible Fish and Marine Invertebrate Tissue

1992 ◽  
Vol 49 (5) ◽  
pp. 1010-1017 ◽  
Author(s):  
Nicolas S. Bloom
Keyword(s):  
Total Mercury ◽  
Marine Invertebrates ◽  
Marine Invertebrate ◽  
Chemical Form ◽  
Weight Basis ◽  
Atomic Fluorescence Spectrometry ◽  
Atomic Fluorescence ◽  
Saltwater Fish ◽  
Relative Standard ◽  
Wet Weight

Total mercury, monomethylmercury (CH3Hg), and dimethylmercury ((CH3)2Hg) in edible muscle were examined in 229 samples, representing seven freshwater and eight saltwater fish species and several species of marine invertebrates using ultraclean techniques. Total mercury was determined by hot HNO3/H2SO4/BrClldigestion, SnCl2 reduction, purging onto gold, and analysis by cold vapor atomic fluorescence spectrometry (CVAFS). Methylmercury was determined by KOH/methanol digestion using aqueous phase ethylation, cryogenic gas chromatography, and CVAFS detection. Total mercury and CH3Hg concentrations varied from 0.011 to 2.78 μg∙g−1 (wet weight basis, as Hg) for all samples, while no sample contained detectable (CH3)2Hg (<0.001 μg∙g−1 as Hg). The observed proportion of total mercury (as CH3Hg) ranged from 69 to 132%, with a relative standard deviation for quintuplicate analysis of about 10%; nearly all of this variability can be explained by the analytical variability of total mercury and CH3Hg. Poorly homogenized samples showed greater variability, primarily because total mercury and CH3Hg were measured on separate aliquots, which vary in mercury concentration, not speciation. I conclude that for all species studied, virtually ail (>95%) of the mercury present is as CH3Hg and that past reports of substantially lower CH3Hg fractions may have been biased by analytical and homogeneity variability.

III.—The Life-history and Cytology of Didymium nigripes Fr.

1932 ◽  
Vol 57 (1) ◽  
pp. 93-142 ◽  
Author(s):  
Elsie J. Cadman
Keyword(s):  
Life History ◽  
Life Histories ◽  
Important Research ◽  
Great Work ◽  
Animal Kingdom ◽  
History Of ◽  
Natural Groups

Since 1860, in which year De Bary published his great work Die Mycetozoen, the investigation of the life-history of members of the Mycetozoa has aroused a considerable amount of interest, and a great deal of important research has been carried out in this connection. The group of organisms is particularly interesting, because it lies on the borderline between plant and animal kingdoms, and it is very possible that a detailed investigation of several species of the Mycetozoa might be of considerable assistance in elucidating certain obscure points in the life-histories of higher members of both the great natural groups. The term “Mycetozoa,” which we owe to De Bary, will be used throughout in preference to the older term “Myxogastres” invented by Fries (32, p. 2), and that of “Myxomycetes” first employed by Link (32, p. 2). “Mycetozoon,” or “fungus-like animal,” is a very appropriate description of a member of the group, since during part of its life-history it exhibits distinctly animal-like characters, and the individuals move rapidly by means of flagella, whilst later, during the development of the sporangium, a plant-like form is assumed. The combination of plant and animal characters has given rise to much discussion as to the position of the Mycetozoa in plant or animal kingdom, and the group has been claimed by both zoologists and botanists.

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