scholarly journals A contemplation on the secondary origin of green algal and plant plastids

2014 ◽  
Vol 83 (4) ◽  
pp. 331-336 ◽  
Author(s):  
Eunsoo Kim ◽  
Shinichiro Maruyama
Keyword(s):  
Land Plants ◽  
Single Origin ◽  
Phylogenetic Studies ◽  
Green Algal ◽  
Secondary Origin ◽  
Primary Plastid ◽  
Evolutionary Studies ◽  
New Hypothesis ◽  
Existing Data ◽  
Lines Of Evidence

A single origin of plastids and the monophyly of three “primary” plastid-containing groups – the Chloroplastida (or Viridiplantae; green algae+land plants), Rhodophyta, and Glaucophyta – are widely accepted, mainstream hypotheses that form the basis for many comparative evolutionary studies. This “Archaeplastida” hypothesis, however, thus far has not been unambiguously confirmed by phylogenetic studies based on nucleocytoplasmic markers. In view of this as well as other lines of evidence, we suggest the testing of an alternate hypothesis that plastids of the Chloroplastida are of secondary origin. The new hypothesis is in agreement with, or perhaps better explains, existing data, including both the plastidal and nucleocytoplasmic characteristics of the Chloroplastida in comparison to those of other groups.

scholarly journals The Pathogenesis of Adenomyosis vis-à-vis Endometriosis

2020 ◽  
Vol 9 (2) ◽  
pp. 485 ◽  
Author(s):  
Guo
Keyword(s):  
Epithelial Mesenchymal Transition ◽  
Tissue Injury ◽  
Salient Feature ◽  
Deep Endometriosis ◽  
Mesenchymal Transition ◽  
Endometrial Cells ◽  
Iatrogenic Trauma ◽  
Injury And Repair ◽  
New Hypothesis ◽  
Existing Data

Adenomyosis is used to be called endometriosis interna, and deep endometriosis is now called adenomyosis externa. Thus, there is a question as to whether adenomyosis is simply endometriosis of the uterus, either from the perspective of pathogenesis or pathophysiology. In this manuscript, a comprehensive review was performed with a literature search using PubMed for all publications in English, related to adenomyosis and endometriosis, from inception to June 20, 2019. In addition, two prevailing theories, i.e., invagination—based on tissue injury and repair (TIAR) hypothesis—and metaplasia, on adenomyosis pathogenesis, are briefly overviewed and then critically scrutinized. Both theories have apparent limitations, i.e., difficulty in falsification, explaining existing data, and making useful predictions. Based on the current understanding of wound healing, a new hypothesis, called endometrial-myometrial interface disruption (EMID), is proposed to account for adenomyosis resulting from iatrogenic trauma to EMI. The EMID hypothesis not only highlights the more salient feature, i.e., hypoxia, at the wounding site, but also incorporates epithelial mesenchymal transition, recruitment of bone-marrow-derived stem cells, and enhanced survival and dissemination of endometrial cells dispersed and displaced due to iatrogenic procedures. More importantly, the EMID hypothesis predicts that the risk of adenomyosis can be reduced if certain perioperative interventions are performed. Consequently, from a pathogenic standpoint, adenomyosis is not simply endometriosis of the uterus, and, as such, may call for interventional procedures that are somewhat different from those for endometriosis to achieve the best results.

scholarly journals The dawn of symbiosis between plants and fungi

2011 ◽  
Vol 7 (4) ◽  
pp. 574-577 ◽  
Author(s):  
Martin I. Bidartondo ◽  
David J. Read ◽  
James M. Trappe ◽  
Vincent Merckx ◽  
Roberto Ligrone ◽  
...  
Keyword(s):  
Vascular Plant ◽  
Land Plants ◽  
Evolutionary Trees ◽  
Early Devonian ◽  
Present Evidence ◽  
Plant Fossils ◽  
Biological Innovations ◽  
New Hypothesis ◽  
Colonization Of Land ◽  
Early Land

The colonization of land by plants relied on fundamental biological innovations, among which was symbiosis with fungi to enhance nutrient uptake. Here we present evidence that several species representing the earliest groups of land plants are symbiotic with fungi of the Mucoromycotina. This finding brings up the possibility that terrestrialization was facilitated by these fungi rather than, as conventionally proposed, by members of the Glomeromycota. Since the 1970s it has been assumed, largely from the observation that vascular plant fossils of the early Devonian (400 Ma) show arbuscule-like structures, that fungi of the Glomeromycota were the earliest to form mycorrhizas, and evolutionary trees have, until now, placed Glomeromycota as the oldest known lineage of endomycorrhizal fungi. Our observation that Endogone -like fungi are widely associated with the earliest branching land plants, and give way to glomeromycotan fungi in later lineages, raises the new hypothesis that members of the Mucoromycotina rather than the Glomeromycota enabled the establishment and growth of early land colonists.

A rationale for evolutionary studies of literature

2013 ◽  
Vol 3 (1) ◽  
pp. 8-15 ◽  
Author(s):  
Joseph Carroll
Keyword(s):  
Conceptual Framework ◽  
Literary Theory ◽  
Environmental Influences ◽  
Human Mind ◽  
Adaptive Function ◽  
Evolutionary Studies ◽  
The Mind ◽  
Genetically Determined ◽  
By Products ◽  
Lines Of Evidence

I identify converging lines of evidence for the proposition that the human mind has evolved, argue that the evolved character of the mind influences the products of the mind, including literature, and conclude that scholarly and scientific commentary on literature would benefit from being explicitly lodged within an evolutionary conceptual framework. I argue that a biocultural perspective has comprehensive scope and can encompass all the topics to which other schools of literary theory give attention. To support this contention, I appeal to axiomatic logic: the behavior of any organism is a result of interactions between its genetically determined characteristics and its environmental influences. Summarizing the debate over the adaptive function of literature, I argue that literature and its oral antecedents are adaptations, not merely by-products of adaptations.

The Evolution of Monogamy in Large Primates: a New Hypothesis and Some Crucial Tests

Behaviour ◽  
1990 ◽  
Vol 115 (1-2) ◽  
pp. 30-61 ◽  
Author(s):  
C.P. VAN SCHAIK ◽  
R.I.M. Dunbar
Keyword(s):  
Reproductive Output ◽  
Selective Pressures ◽  
Male Care ◽  
Feeding Area ◽  
New Hypothesis ◽  
Existing Data

AbstractMonogamy among the large primates is not accompanied by high levels of male care for infants. The selective pressures that have led to its evolution in this case are far from clear. In this paper, we evaluate and test four different hypotheses. Monogamy in these species did not evolve because males are unable to defend access to more than one female. Hence, it must be related to behavioural services provided by the male which substantially increase the female's reproductive output. Existing data argue against the suggestion that these services involve protection against predators or defence of an exclusive feeding area. We propose that the male's service consists primarily in protecting the female against infanticide by other males. Tests that would differentiate this hypothesis unequivocally from other hypotheses are suggested. To the extent that these predictions can be tested with the data currently available, the evidence supports the infanticide hypothesis. We speculate that infanticide avoidance is also responsible for the near-universal occurrence among primates of male-female bonds.

A model for transepithelial fluid transport

1978 ◽  
Vol 235 (6) ◽  
pp. F626-F637 ◽  
Author(s):  
E. H. Bresler
Keyword(s):  
Simple Model ◽  
Hydraulic Conductivity ◽  
Sodium Transport ◽  
Fluid Transport ◽  
Reflection Coefficients ◽  
Active Sodium ◽  
Active Sodium Transport ◽  
Existing Data ◽  
Lines Of Evidence

A number of experimental observations which are not easily, or at all, accommodated within the framework of the natriocentric theory for transepithelial fluid transport are discussed. These are shown to be not merely accommodated but actually predicted by a simple model for fluid transport in which the major osmotic force leading to fluid transport derives from solutes other than NaCl. The model is then analyzed for feasibility in light of existing data relating to reflection coefficients for NaCl and hydraulic conductivity. Certain lines of evidence for specific active sodium transport are critically reexamined.

The gain of two chloroplast tRNA introns marks the green algal ancestors of land plants

Nature ◽  
1990 ◽  
Vol 345 (6272) ◽  
pp. 268-270 ◽  
Author(s):  
J. R. Manhart ◽  
J. D. Palmer
Keyword(s):  
Land Plants ◽  
Green Algal

scholarly journals The microfossil record of early land plants

2000 ◽  
Vol 355 (1398) ◽  
pp. 717-732 ◽  
Author(s):  
Charles H. Wellman ◽  
Jane Gray
Keyword(s):  
Fossil Record ◽  
Vascular Plants ◽  
Major Change ◽  
Land Plant ◽  
Land Plants ◽  
Early Land Plant ◽  
Early Late ◽  
Early Land ◽  
Lines Of Evidence ◽  
Plant Microfossil

Dispersed microfossils (spores and phytodebris) provide the earliest evidence for land plants. They are first reported from the Llanvirn (Mid–Ordovician). More or less identical assemblages occur from the Llanvirn (Mid–Ordovician) to the late Llandovery (Early Silurian), suggesting a period of relative stasis some 40 Myr in duration. Various lines of evidence suggest that these early dispersed microfossils derive from parent plants that were bryophyte–like if not in fact bryophytes. In the late Llandovery (late Early Silurian) there was a major change in the nature of dispersed spore assemblages as the separated products of dyads (hilate monads) and tetrads (trilete spores) became relatively abundant. The inception of trilete spores probably represents the appearance of vascular plants or their immediate progenitors. A little later in time, in the Wenlock (early Late Silurian), the earliest unequivocal land plant megafossils occur. They are represented by rhyniophytoids. It is only from the Late Silurian onwards that the microfossil / megafossil record can be integrated and utilized in interpretation of the flora. Dispersed microfossils are preserved in vast numbers, in a variety of environments, and have a reasonable spatial and temporal fossil record. The fossil record of plant megafossils by comparison is poor and biased, with only a dozen or so known pre–Devonian assemblages. In this paper, the early land plant microfossil record, and its interpretation, are reviewed. New discoveries, novel techniques and fresh lines of inquiry are outlined and discussed.

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