scholarly journals Morpho-anatomical differences among mycoheterotrophic Afrothismia spp. (Thismiaceae) indicate an evolutionary progression towards improved mycorrhizal benefit

Mycorrhiza ◽  
2020 ◽  
Vol 30 (2-3) ◽  
pp. 397-405
Author(s):  
Stephan Imhof ◽  
Benjamin Feller ◽  
Anna Heser
Keyword(s):  
Evolutionary Progression

scholarly journals Modular evolution of phosphorylation-based signalling systems

2012 ◽  
Vol 367 (1602) ◽  
pp. 2540-2555 ◽  
Author(s):  
Jing Jin ◽  
Tony Pawson
Keyword(s):  
Protein Kinases ◽  
Genetic Recombination ◽  
Cell Signalling ◽  
Peptide Motifs ◽  
Regulatory Processes ◽  
Modular Evolution ◽  
Interaction Domains ◽  
Evolutionary Progression ◽  
Signalling Systems ◽  
Selection Of

Phosphorylation sites are formed by protein kinases (‘writers’), frequently exert their effects following recognition by phospho-binding proteins (‘readers’) and are removed by protein phosphatases (‘erasers’). This writer–reader–eraser toolkit allows phosphorylation events to control a broad range of regulatory processes, and has been pivotal in the evolution of new functions required for the development of multi-cellular animals. The proteins that comprise this system of protein kinases, phospho-binding targets and phosphatases are typically modular in organization, in the sense that they are composed of multiple globular domains and smaller peptide motifs with binding or catalytic properties. The linkage of these binding and catalytic modules in new ways through genetic recombination, and the selection of particular domain combinations, has promoted the evolution of novel, biologically useful processes. Conversely, the joining of domains in aberrant combinations can subvert cell signalling and be causative in diseases such as cancer. Major inventions such as phosphotyrosine (pTyr)-mediated signalling that flourished in the first multi-cellular animals and their immediate predecessors resulted from stepwise evolutionary progression. This involved changes in the binding properties of interaction domains such as SH2 and their linkage to new domain types, and alterations in the catalytic specificities of kinases and phosphatases. This review will focus on the modular aspects of signalling networks and the mechanism by which they may have evolved.

Taxonomic implications and evolutionary trends in pollen of Canadian Ericales

1986 ◽  
Vol 64 (12) ◽  
pp. 3113-3126 ◽  
Author(s):  
Barry G. Warner ◽  
C. C. Chinnappa
Keyword(s):  
Pollen Morphology ◽  
Evolutionary Relationships ◽  
Evolutionary Trends ◽  
Fungal Symbiont ◽  
Pollen Types ◽  
Taxonomic Implications ◽  
The Individual ◽  
Individual Grains ◽  
Evolutionary Progression ◽  
Scanning Electron

The pollen of 61 of about 80 taxa of Ericales that occur in Canada are described through the use of light and scanning electron microscopy. Five main pollen types are recognized: (I) compact tetrads in which the individual grains are not clearly delimited when rolled and viewed in all positions, and possessing costae endopori or costae endocolpi, (II) tetrads in which the individual grains are clearly and consistently delimited, occasionally possessing costae endopori or costae endocolpi, (III) a category in which grains within the tetrad are not consistently delimited, and lack costae endopori or costae endocolpi, (IV) loose tetrads in which individual grains are poorly fused, and (V) monads. A key identifies general morphological distinctions among the pollen groups or species. This survey of the pollen morphology of the Ericales supports conventional taxonomic treatments. We favour treatment of Monotropaceae and Pyrolaceae as separate families and suggest the elevation of Orthila secunda to its own monotypic family. The Clethraceae and Orthila secunda may be better treated outside the Ericales. We propose that the tetrad pollen of most Ericales is a derived condition from the more primitive trizonocolporate monad of the Cyrillaceae, Clethraceae, and Orthila secunda. Subfamily Vaccinioideae (Ericaceae) and Empetraceae, through subfamily Rhododendroideae (Ericaceae), to Pyrola and Moneses (Pyrolaceae), and finally to Chimaphila (Pyrolaceae) represent the evolutionary progression based on a trend from compact tetrads to loose individual grains within the tetrad. Finally the most advanced group is represented by the zonoaperturate monads of the Monotropaceae. This evolutionary progression based on pollen morphology is in accord with general principles of tetrad formation during microsporogenesis and with evolutionary relationships suggested by the macromorphology, phytochemistry, embryology, and degree of dependence on a fungal symbiont.

Objections and Anxieties

2015 ◽  
Author(s):  
Richard Susskind ◽  
Daniel Susskind
Keyword(s):  
Big Bang ◽  
Professional Society ◽  
Industrial Society ◽  
Daily Lives ◽  
The Future ◽  
Specialist Knowledge ◽  
Evolutionary Progression ◽  
The Way

We surface now from our theorizing in Part II to address more practical matters. Roughly speaking, the story so far is this—the professions are our current solution to a pervasive problem, namely, that none of us has sufficient specialist knowledge to allow us to cope with all the challenges that life throws at us. We have limited understanding, and so we turn to doctors, lawyers, teachers, architects, and other professionals because they have ‘practical expertise’ that we need to bring to bear in our daily lives. In a print-based industrial society, we have interposed the professions, as gatekeepers, between individuals and organizations and the knowledge and experience to which they need access. In the first two parts of the book we describe the changes taking place within the professions, and we develop various theories (largely technological and economic) that lead us to conclude that, in the future—in the fully fledged, technology-based Internet society—increasingly capable machines, autonomously or with non-specialist users, will take on many of the tasks that currently are the exclusive realm of the professions. While we do not anticipate an overnight, big-bang revolution, equally we do not expect a leisurely evolutionary progression into the post-professional society. Instead, we predict what we call an ‘incremental transformation’ in the way in which we organize and share expertise in society, a displacement of the traditional professions in a staggered series of steps and bounds. Although the change will come in increments, its eventual impact will be radical and pervasive. Our personal inclination, articulated at greater length in the Conclusion, is to be strongly sympathetic to this transformation. Our professions are creaking—they are increasingly unaffordable and inaccessible, and suffer from numerous other defects besides, as we describe in section 1.7. Change is long overdue. In conversation with mainstream professionals, in response to our thinking, two words in juxtaposition are uttered again and again—‘yes but . . . ’. Sometimes, what then follows is the special pleading that we note in section 1.9—professionals argue that our thinking applies to all professions other than their own.

scholarly journals Whole-proteome tree of life suggests a deep burst of organism diversity

2020 ◽  
Vol 117 (7) ◽  
pp. 3678-3686 ◽  
Author(s):  
JaeJin Choi ◽  
Sung-Hou Kim
Keyword(s):  
Information Theory ◽  
Genome Sequence ◽  
Tree Of Life ◽  
Whole Genome Sequence ◽  
Whole Genome ◽  
Genome Sequences ◽  
Alignment Free ◽  
Whole Transcriptome ◽  
Evolutionary Progression ◽  
Feature Frequency

An organism tree of life (organism ToL) is a conceptual and metaphorical tree to capture a simplified narrative of the evolutionary course and kinship among the extant organisms. Such a tree cannot be experimentally validated but may be reconstructed based on characteristics associated with the organisms. Since the whole-genome sequence of an organism is, at present, the most comprehensive descriptor of the organism, a whole-genome sequence-based ToL can be an empirically derivable surrogate for the organism ToL. However, experimentally determining the whole-genome sequences of many diverse organisms was practically impossible until recently. We have constructed three types of ToLs for diversely sampled organisms using the sequences of whole genome, of whole transcriptome, and of whole proteome. Of the three, whole-proteome sequence-based ToL (whole-proteome ToL), constructed by applying information theory-based feature frequency profile method, an “alignment-free” method, gave the most topologically stable ToL. Here, we describe the main features of a whole-proteome ToL for 4,023 species with known complete or almost complete genome sequences on grouping and kinship among the groups at deep evolutionary levels. The ToL reveals 1) all extant organisms of this study can be grouped into 2 “Supergroups,” 6 “Major Groups,” or 35+ “Groups”; 2) the order of emergence of the “founders” of all of the groups may be assigned on an evolutionary progression scale; 3) all of the founders of the groups have emerged in a “deep burst” at the very beginning period near the root of the ToL—an explosive birth of life’s diversity.

Alphacrinus new genus and origin of the disparid clade

2010 ◽  
Vol 84 (6) ◽  
pp. 1209-1216 ◽  
Author(s):  
Thomas E. Guensburg
Keyword(s):  
New Genus ◽  
New Genus And Species ◽  
New Family ◽  
Evolutionary Progression

Alphacrinus mansfieldi new genus and species from the Middle Tremadoc Series (Early Ibexian), near the base of the Ordovician, is the oldest known disparid crinoid. A new family, Alphacrinidae, receives this monospecific genus. Alphacrinus's character mosaic includes primitive traits unknown among other disparids, auguring for disparid origin from a more complexly plated, less standardized antecedent, and echoing the evolutionary progression documented for camerates and cladids. Disparids are diagnosed as those crinoids expressing an arm-like branch from the C ray. Morphologic progression indicates this distinctive trait evolved by modification of CD interray plates, not as an outgrowth from the C ray.

scholarly journals A global perspective of codon usage

2016 ◽  
Author(s):  
Bohdan B. Khomtchouk ◽  
Claes Wahlestedt ◽  
Wolfgang Nonner
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Codon Usage ◽  
Genetic Code ◽  
Common Ancestor ◽  
Tree Of Life ◽  
Last Universal Common Ancestor ◽  
Synonymous Codons ◽  
Universal Common Ancestor ◽  
Evolutionary Progression

Codon usage in 2730 genomes is analyzed for evolutionary patterns in the usage of synonymous codons and amino acids across prokaryotic and eukaryotic taxa. We group genomes together that have similar amounts of intra-genomic bias in their codon usage, and then compare how usage of particular different codons is diversified across each genome group, and how that usage varies from group to group. Inter-genomic diversity of codon usage increases with intra-genomic usage bias, following a universal pattern. The frequencies of the different codons vary in robust mutual correlation, and the implied synonymous codon and amino acid usages drift together. This kind of correlation indicates that the variation of codon usage across organisms is chiefly a consequence of lateral DNA transfer among diverse organisms. The group of genomes with the greatest intra-genomic bias comprises two distinct subgroups, with each one restricting its codon usage to essentially one unique half of the genetic code table. These organisms include eubacteria and archaea thought to be closest to the hypothesized last universal common ancestor (LUCA). Their codon usages imply genetic diversity near the hypothesized base of the tree of life. There is a continuous evolutionary progression across taxa from the two extremely diversified usages toward balanced usage of different codons (as approached, e.g. in mammals). In that progression, codon frequency variations are correlated as expected from a blending of the two extreme codon usages seen in prokaryotes.AUTHOR SUMMARYThe redundancy intrinsic to the genetic code allows different amino acids to be encoded by up to six synonymous codons. Genomes of different organisms prefer different synonymous codons, a phenomenon known as ‘codon usage bias.’ The phenomenon of codon usage bias is of fundamental interest for evolutionary biology, and is important in a variety of applied settings (e.g., transgene expression). The spectrum of codon usage biases seen in current organisms is commonly thought to have arisen by the combined actions of mutations and selective pressures. This view focuses on codon usage in specific genomes and the consequences of that usage for protein expression.Here we investigate an unresolved question of molecular genetics: are there global rules governing the usage of synonymous codons made by genomic DNA across organisms? To answer this question, we employed a data-driven approach to surveying 2730 species from all kingdoms of the ‘tree of life’ in order to classify their codon usage. A first major result was that the large majority of these organisms use codons rather uniformly on the genome-wide scale, without giving preference to particular codons among possible synonymous alternatives. A second major result was that two compartments of codon usage seem to co-exist and to be expressed in different proportions by different organisms. As such, we investigate how individual different codons are used in different organisms from all taxa. Whereas codon usage is generally believed to be the evolutionary result of both mutations and natural selection, our results suggest a different perspective: the usage of different codons (and amino acids) by different organisms follows a superposition of two distinct patterns of usage. One distinction locates to the third base pair of all different codons, which in one pattern is U or A, and in the other pattern is G or C. This result has two major implications: (1) the variation of codon usage as seen across different organisms is best accounted for by lateral gene transfer among diverse organisms; (2) the organisms that are by protein homology grouped near the base of the ‘tree of life’ comprise two genetically distinct lineages.We find that, over evolutionary time, codon usages have converged from two distinct, non-overlapping usages (e.g., as evident in bacteria and archaea) to a near-uniform, balanced usage of synonymous codons (e.g., in mammals). This shows that the variations of codon (and amino acid) biases reveal a distinct evolutionary progression. We also find that codon usage in bacteria and archaea is most diverse between organisms thought to be closest to the hypothesized last universal common ancestor (LUCA). The dichotomy in codon (and amino acid usages) present near the origin of the current ‘tree of life’ might provide information about the evolutionary development of the genetic code.

scholarly journals Hemostasis in Nonmammalian Vertebrates: An Overview

1977 ◽  
Author(s):  
Jean W. Dodds
Keyword(s):  
Cell Aggregation ◽  
Lower Vertebrate ◽  
Plasma Coagulation ◽  
Bony Fishes ◽  
Coagulation Mechanism ◽  
Major Factors ◽  
Plasma Factors ◽  
Plug Formation ◽  
Exact Relationship ◽  
Evolutionary Progression

A common feature of comparative hemostasis throughout the animal kingdom is the participation of cell aggregation and plasma coagulation processes in the sealing of wounds. This applies to many invertebrates and all vertebrates. It is tempting therefore to assume a direct evolutionary progression from primitive invertebrates to advanced vertebrates. The major factors contributing to hemostatic plug formation and dissolution (vessel contraction, plasma coagulation, platelet or thrombocyte reactions and fibrinolysis) are present to greater or lesser extent in most nonmammalian vertebrates including Cyclostomes, Elasmobranchs, Bony Fishes, Amphibians, Reptiles and Birds. Of these functions, the thrombin-fibrinogen reaction has evolved as the final stage of the coagulation mechanism of all vertebrates. Prothrombin conversion to thrombin, accomplished by a tissue factor, is also common to all classes of vertebrates although the plasma factors involved in prothrombin activation have not been delineated for many lower forms of vertebrates. Similarly the exact relationship between the various types of cells involved in hemostasis has yet to be established. Although mammalian platelets probably were derived from invertebrate and lower vertebrate thrombocytes, this is yet to be proven. The challenge remains to develop a more thorough understanding of the basic mechanisms of hemostasis and thereby provide additional biochemical evidence for evolutionary progression.

Darwinism as Religion

2018 ◽  
Author(s):  
Michael Ruse
Keyword(s):  
Natural Selection ◽  
Seminal Fluid ◽  
Julian Huxley ◽  
The Social ◽  
Alternative Religion ◽  
Illicit Use ◽  
Secular Religion ◽  
Evolutionary Progression ◽  
The Way

This chapter prepares the way for the purpose of the book, to use war as a case study for the claim that in major respects, thinking based on Darwin’s ideas—“Darwinism”—has from the first functioned as a form of secular religion, a variety of humanism. Although natural selection makes it very implausible to claim that there is an inevitable evolutionary progression up to humankind, this has not stopped Darwinians, from Darwin himself through to people like Edward O. Wilson today, seeing such progress and using this belief as a peg on which to hang social and moral views, in major respects alternatives to the social and moral views of Christianity. Often, as in the case of Julian Huxley, the intent to produce an alternative religion is made explicit. Rival views on the illicit use of seminal fluid are used as an illustration. For Christians, through self-abuse, it leads to degeneration. For Darwinians, through the failures of the sexually profligate, it leads to advance.

Appalachian Peneplains: An Historical Review

1983 ◽  
Vol 2 (2) ◽  
pp. 156-164 ◽  
Author(s):  
William Sevon ◽  
Noel Potter ◽  
George Crowl
Keyword(s):  
Early Identification ◽  
Dynamic Equilibrium ◽  
Historical Review ◽  
Mineral Resources ◽  
Equilibrium Concept ◽  
Long Period ◽  
Surficial Deposits ◽  
Relationship Of ◽  
The Relationship ◽  
Evolutionary Progression

The concept that erosion, over a long period of time, would produce an evolutionary progression of landforms culminating in a nearly flat plain, the peneplain, was formulated into a coherent theory by W. M. Davis. Subsequent to early identification of the Fall Zone (oldest), Schooley, Harrisburg, and Somerville (youngest) peneplains, numerous workers pursued identification, correlation, description, folding, formative processes, and dating of Appalachian peneplains for 6 decades. Following a peak of interest and activity in the 1930's, work on Appalachian peneplains declined rapidly. Reasons for the decline include: death of former workers, diversion into other lines of research, and rise of process geomorphology. Phenomena attributed to a dependence on peneplanation include: origin of present drainage, origin of some mineral resources, and cementation of rock units. Attacks on the peneplain idea have been largely unsuccessful except for the dynamic equilibrium concept advocated by John Hack. Controversy exists about whether the disparity between rates of uplift and denundation allow adequate time for peneplanation to occur. The relationship of some surficial deposits to presumed peneplain surfaces is problematical. The peneplain concept is still alive, but new lines of research are required to resolve its controversial position.

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