Morphological Evolution, Adaptations, Homoplasies, Constraints, and Evolutionary Trends

2004 ◽  
Author(s):  
Rui Diogo
Keyword(s):  
Morphological Evolution ◽  
Evolutionary Trends

scholarly journals New evidence on the origin of non-spinose pitted–cancellate species of the early Danian planktonic foraminifera

2013 ◽  
Vol 64 (3) ◽  
pp. 237-251 ◽  
Author(s):  
Ignacio Arenillas ◽  
Jose Antonio Arz
Keyword(s):  
Morphological Evolution ◽  
Planktonic Foraminifera ◽  
Middle Part ◽  
External Morphology ◽  
Evolutionary Trends ◽  
Test Size ◽  
Evolutionary Path ◽  
Origin And Evolution ◽  
Large Pore ◽  
New Evidence

Abstract Intermediate forms identified in some of the most continuous lower Danian sections allow a better understanding of the origin and evolution of pitted (Globanomalina) and cancellate (Praemurica) planktonic foraminifera. Both Globanomalina and Praemurica are part of a major Paleocene lineage, namely the “non-spinose lineage”, which started to diverge in the early Danian. Transitional specimens strongly suggest the evolution from Parvularugoglobigerina to Globanomalina, and then to Praemurica. These evolutionary turnovers were quite rapid (probably lasting less than 10 kyr), and seem to have begun in the time equivalent of the lower part of the E. simplicissima Subzone, namely the middle part of the standard Zone Pa. The initial evolutionary trends within this non-spinose lineage were the increase of test size and lip thickness, and the evolution from tiny pore-murals to large pore-pits, and from smooth to pitted and finally cancellate walls. Biostratigraphic data suggest that evolution of the wall texture preceded the morphological evolution within each genus. The oldest species of both Globanomalina and Praemurica, namely G. archeocompressa and Pr. taurica, initially retained the external morphology of the ancestral Parvularugoglobigerina eugubina. Since their divergence, Globanomalina and Praemurica followed a separate evolutionary path, evolving into morphologically different species.

scholarly journals General regularities in the development Gzhelian-Asselian conodonts

LITOSFERA ◽  
2020 ◽  
Vol 20 (4) ◽  
pp. 471-485
Author(s):  
V. V. Chernykh
Keyword(s):  
Related Species ◽  
Morphological Evolution ◽  
Lower Boundary ◽  
Wide Distribution ◽  
Evolutionary Development ◽  
Evolutionary Trends ◽  
Gradual Development ◽  
Cyclic Type ◽  
Directed Change ◽  
Rapid Appearance

Subject of study. The features of the evolutionary changing of Gzhelian-Asselian conodonts are examined. Materials. The data on Ural and North American conodonts are used. Results. The cyclic type of change of the Pa-element morphology in the process of the evolutionary development of the representatives of the genus Streptognathodus is established. Morphological evolutionary trends of gradual development alternate with the periods of the rapid appearance of a group of the forms of original constitution. The species of this group are characterized by wide distribution and short lifetime. Such species are used as the markers of the boundaries of stratigraphic subdivisions. Lower boundary of Gzhelian is determined by the appearance of species of the group simulator; the species of group isolatus mark lower boundary of Asselian. Model of the ensemble evolution of the related species is used for explaining the directed change in the morphology of conodonts. The saltational appearance of the determined indication is explained by the phenomenon of evolutionary oscillations. Conclusion. We can make conclusion about the sexual multiplication of this group of the organisms according the established alternation of the periods of the slow and rapid morphological evolution of conodonts.

Biosystematic studies in the North American species of Linum, section Adenolinum (Linaceae)

1971 ◽  
Vol 49 (8) ◽  
pp. 1379-1388 ◽  
Author(s):  
Theodore Mosquin
Keyword(s):  
North American ◽  
Morphological Evolution ◽  
North American Species ◽  
Evolutionary Trends ◽  
Isolated Populations ◽  
Life Habit ◽  
Good Pollen ◽  
The North ◽  
Native North American ◽  
Variation Patterns

Variation patterns and interpopulational relationships were examined in Linum lewisii Pursh and L. pratense (Norton) Small, the two native North American blue-flowered flax species. The two principal evolutionary trends in the North American populations have been toward self-pollination and an annual life habit. A third trend, toward greater outcrossing, is considered probable. Hybridizations between and within species indicate that evolution has occurred mainly by the accumulation of small genic changes in geographically isolated populations. The buildup of sterility barriers between populations regardless of species has not been extensive and in no case do hybrids have less than 30% good pollen. In general, morphological evolution has occurred independently of the buildup of sterility barriers. A new taxonomic combination, L. lewisii ssp. lepagei (Boivin) Mosquin, is adopted.

Constraint and adaptation in the bone-cracking canid Osteoborus (Mammalia: Canidae)

Paleobiology ◽  
1989 ◽  
Vol 15 (4) ◽  
pp. 387-401 ◽  
Author(s):  
Lars Werdelin
Keyword(s):  
North America ◽  
Morphological Evolution ◽  
Evolutionary Trend ◽  
Evolutionary Trends ◽  
Dual Purpose ◽  
Strong Forces

The borophagine canids were bone-cracking scavengers in the Miocene-Pleistocene of North America. In this they parallel the Recent hyenas. This paper analyzes the borophagine adaptation in relation to that of hyaenids, using Osteoborus cyonoides as an example. The emphasis during canid evolution on the posterior molars, which is a derived condition, created a constraint on the adaptation of borophagines. This constraint meant that the borophagines used P4/4 as bone-cracking teeth, whereas hyaenids use P3/3. The latter adaptation has the advantage of separating the bone-cracking teeth from the meat-cutting portion of the dentition, thereby allowing a dual purpose dentition in hyaenids. In borophagines, no such dual purpose was possible, and it is suggested that they were closer to obligate bone-cracking scavengers than Recent hyaenids. Other than the evolution of a specialized bone-cracking tooth, the borophagines adapted to bone cracking by evolving a vaulted and strengthened skull for the dissipation of the strong forces generated during bone cracking. In this they again parallel the hyaenids. Evolution within borophagines involved an elaboration of patterns already set at the group's inception, creating an evolutionary trend which was mediated by the constraint on the bone-cracking morphology. This trend may be due to selection or sorting, or may, under certain assumptions, be stochastic. Other evolutionary trends may also be epiphenomena of constraints that lock morphological evolution.

scholarly journals New Avenues for Old Travellers: Phenotypic Evolutionary Trends Meet Morphodynamics, and Both Enter the Global Change Biology Era

2021 ◽  
Author(s):  
Davide Tamagnini ◽  
Daniele Canestrelli ◽  
Carlo Meloro ◽  
Pasquale Raia ◽  
Luigi Maiorano
Keyword(s):  
Global Change ◽  
Evolutionary Biology ◽  
Evolutionary Dynamics ◽  
Morphological Evolution ◽  
Parallel Evolution ◽  
Evolutionary Trends ◽  
Evolutionary Pattern ◽  
Directional Evolution ◽  
Definition Of ◽  
The Impact

AbstractEvolutionary trends (ETs) are traditionally defined as substantial changes in the state of traits through time produced by a persistent condition of directional evolution. ETs might also include directional responses to ecological, climatic or biological gradients and represent the primary evolutionary pattern at high taxonomic levels and over long-time scales. The absence of a well-supported operative definition of ETs blurred the definition of conceptual differences between ETs and other key concepts in evolution such as convergence, parallel evolution, and divergence. Also, it prevented the formulation of modern guidelines for studying ETs and evolutionary dynamics related to them. In phenotypic evolution, the theory of morphodynamics states that the interplay between evolutionary factors such as phylogeny, evo-devo constraints, environment, and biological function determines morphological evolution. After introducing a new operative definition, here we provide a morphodynamics-based framework for studying phenotypic ETs, discussing how understanding the impact of these factors on ETs improves the explanation of links between biological patterns and processes underpinning directional evolution. We envisage that adopting a quantitative, pattern-based, and multifactorial approach will pave the way to new potential applications for this field of evolutionary biology. In this framework, by exploiting the catalysing effect of climate change on evolution, research on ETs induced by global change might represent an ideal arena for validating hypotheses about the predictability of evolution.

A quantitative image analysis method for the determination of cocontinuity in polymer blends

1993 ◽  
Vol 51 ◽  
pp. 894-895
Author(s):  
William A. Heeschen
Keyword(s):  
Image Analysis ◽  
Polymer Blends ◽  
Quantitative Measurement ◽  
Morphological Evolution ◽  
Phase Ratio ◽  
Irregular Shapes ◽  
Quantitative Image ◽  
Discrete Domains ◽  
A Domains

Two new morphological measurements based on digital image analysis, CoContinuity and CoContinuity Balance, have been developed and implemented for quantitative measurement of morphology in polymer blends. The morphology of polymer blends varies with phase ratio, composition and processing. A typical morphological evolution for increasing phase ratio of polymer A to polymer B starts with discrete domains of A in a matrix of B (A/B < 1), moves through a cocontinuous distribution of A and B (A/B ≈ 1) and finishes with discrete domains of B in a matrix of A (A/B > 1). For low phase ratios, A is often seen as solid convex particles embedded in the continuous B phase. As the ratio increases, A domains begin to evolve into irregular shapes, though still recognizable as separate domains. Further increase in the phase ratio leads to A domains which extend into and surround the B phase while the B phase simultaneously extends into and surrounds the A phase.

Operando Visualization of Morphological Dynamics in All-Solid-State Batteries

2019 ◽  
Author(s):  
Xiaohan Wu ◽  
Juliette Billaud ◽  
Iwan Jerjen ◽  
Federica Marone ◽  
Yuya Ishihara ◽  
...  
Keyword(s):  
Solid State ◽  
Solid Electrolytes ◽  
Rational Design ◽  
Morphological Evolution ◽  
Active Material ◽  
Composite Layer ◽  
Transference Number ◽  
Thermal Stabilities ◽  
Solid State Batteries ◽  
All Solid State Batteries

<div> <div> <div> <p>All-solid-state batteries are considered as attractive options for next-generation energy storage owing to the favourable properties (unit transference number and thermal stabilities) of solid electrolytes. However, there are also serious concerns about mechanical deformation of solid electrolytes leading to the degradation of the battery performance. Therefore, understanding the mechanism underlying the electro-mechanical properties in SSBs are essentially important. Here, we show three-dimensional and time-resolved measurements of an all-solid-state cell using synchrotron radiation x-ray tomographic microscopy. We could clearly observe the gradient of the electrochemical reaction and the morphological evolution in the composite layer. Volume expansion/compression of the active material (Sn) was strongly oriented along the thickness of the electrode. While this results in significant deformation (cracking) in the solid electrolyte region, we also find organized cracking patterns depending on the particle size and their arrangements. This study based on operando visualization therefore opens the door towards rational design of particles and electrode morphology for all-solid-state batteries. </p> </div> </div> </div>

Dental Variation in a Collection of Lemmiscus curtatus from the Northern Plains of Southern Saskatchewan: Implications for Morphological Evolution

2019 ◽  
Vol 79 (2) ◽  
pp. 219
Author(s):  
Christopher J. Bell ◽  
Christopher N. Jass ◽  
Robert W. Burroughs
Keyword(s):  
Morphological Evolution ◽  
Northern Plains ◽  
Dental Variation
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