scholarly journals The Legacy of Parker, Baker and Smith 1972: Gamete Competition, the Evolution of Anisogamy, and Model Robustness

Cells ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 573
Author(s):  
Jussi Lehtonen
Keyword(s):  
Analytical Solutions ◽  
Evolutionary History ◽  
Evolutionary Transition ◽  
Central Idea ◽  
Size Dimorphism ◽  
Gamete Competition ◽  
Gamete Size ◽  
Modern Evolutionary Theory ◽  
Model Robustness ◽  
Different Parts

The evolution of anisogamy or gamete size dimorphism is a fundamental transition in evolutionary history, and it is the origin of the female and male sexes. Although mathematical models attempting to explain this transition have been published as early as 1932, the 1972 model of Parker, Baker, and Smith is considered to be the first explanation for the evolution of anisogamy that is consistent with modern evolutionary theory. The central idea of the model is ingenious in its simplicity: selection simultaneously favours large gametes for zygote provisioning, and small gametes for numerical competition, and under certain conditions the outcome is anisogamy. In this article, I derive novel analytical solutions to a 2002 game theoretical update of the 1972 anisogamy model, and use these solutions to examine its robustness to variation in its central assumptions. Combining new results with those from earlier papers, I find that the model is quite robust to variation in its central components. This kind of robustness is crucially important in a model for an early evolutionary transition where we may only have an approximate understanding of constraints that the different parts of the model must obey.

scholarly journals Fusing Logical Relationship Information of Text in Neural Network for Text Classification

2020 ◽  
Vol 2020 ◽  
pp. 1-16 ◽  
Author(s):  
Heyong Wang ◽  
Dehang Zeng
Keyword(s):  
Neural Network ◽  
Text Classification ◽  
Information Science ◽  
Classification Algorithms ◽  
Human Beings ◽  
Central Idea ◽  
Logical Relationship ◽  
The Relationship ◽  
Different Parts ◽  
Better Than

With the development of computer science and information science, text classification technology has been greatly developed and its application scenarios have been widened. In traditional process of text classification, the existing method will lose much logical relationship information of text. The logical relationship information of a text refers to the relationship information among different logical parts of the text, such as title, abstract, and body. When human beings are reading, they will take title as an important part to remind the central idea of the article, abstract as a brief summary of the content of the article, and body as a detailed description of the article. In most of the text classification studies, researchers concern more about the relationship among words (word frequency, semantics, etc.) and neglect the logical relationship information of text. It will lose information about the relationship among different parts (title, body, etc.) and have an influence on the performance of text classification. Therefore, we propose a text classification algorithm—fusing the logical relationship information of text in neural network (FLRIOTINN), which complements the logical relationship information into text classification algorithms. Experiments show that the effect of FLRIOTINN is better than the conventional backpropagation neural networks which does not consider the logical relationship information of text.

scholarly journals Can Palynology be used for Reconstructing the Evolutionary History of Maize Agriculture?

2000 ◽  
Vol 14 (1) ◽  
Author(s):  
Grant D. Zazula
Keyword(s):  
Pollen Analysis ◽  
Evolutionary History ◽  
Morphological Characteristics ◽  
Pollen Grains ◽  
Fossil Pollen ◽  
Evolutionary Transition ◽  
Archaeological Evidence ◽  
Maize Agriculture ◽  
History Of ◽  
Pollen Records

The lack of archaeological or macrobotanical evidence that directly links wild teosinte grass with early domesticated maize requires the exploration of alternative methodologies to document this evolutionary transition. The morphological characteristics and measurements for maize, teosinte and Tripsacum pollen are presented to determine if they display sufficient differentiation to be distinguished in fossil pollen records. Analysis of the data reveals a lack of distinguishing morphological characteristics between the pollen grains of these taxa and prevents palynology from be an effective method in documenting the evolutionary history of maize agriculture. Current methods of pollen analysis cannot be employed to document the evolution of teosinte to maize in the Tehuacan Valley of Mexico and pollen is not likely to provide an earlier record of this transition than what is found in the macrobotanical or archaeological evidence.

Analytical and numerical optimization of gravimetric networks: a case study from Mount Etna, Italy

2020 ◽  
Author(s):  
Mehdi Nikkhoo ◽  
Eleonora Rivalta ◽  
Daniele Carbone ◽  
Flavio Cannavò
Keyword(s):  
Analytical Solutions ◽  
Numerical Optimization ◽  
Optimal Solution ◽  
Optimization Techniques ◽  
Mount Etna ◽  
Mass Change ◽  
Target Zone ◽  
Magmatic Fluids ◽  
The Impact ◽  
Different Parts

<p>The transport of magma and magmatic fluids is a key process behind the occurrence, duration and intensity of volcanic crises. Volcano gravimetry allows for unequivocal inference of the location and mass of accumulated or removed magmatic fluids at volcanoes. This task is best accomplished through collecting gravity time series at multiple stations simultaneously. The performance of individual gravimeters and the configuration of the gravimetric array, however, determine the threshold of detectable mass change and the ability of the array to minimize the uncertainty on the inferred quantities.</p><p>We utilize numerical optimization techniques to design a network including one absolute quantum gravimeter (AQG), two superconducting relative gravimeters (iGRAVs) and several microelectromechanical system (MEMS) relative gravimeters at Mount Etna. We also develop analytical solutions for simple design problems. We show that the analytical solutions are essential for validating the numerical optimization procedure. We provide practical details and caveats that should be considered in similar gravimetric network optimizations. These include 1) specifying the target zone of the network by using the history of mass transport, 2) accounting for the relative importance of  different parts of the target zone, 3) accounting for logistic and instrumental constraints in the optimizations  4) calibrating the objective functions associated with various optimizations, 5) analyzing the network sensitivities to different parts of the target zone and identifying blind zones and  6) calculating the optimal number of gravimeters as a function of the sensor sensitivity and accuracies. We show that our optimal solution for Mount Etna provides an improved detection power across the target zone as compared to an equally spaced network of gravimeters with the same existing constraints, surface topography and sensor sensitivities. Furthermore, this optimal solution ensures that a certain range of mass change anywhere in the target zone can be sensed by a given minimum number of gravimeters and at the same time minimizes the impact of random observation errors on the inferred quantities.</p>

scholarly journals TAS3 miR390-dependent loci in non-vascular land plants: Towards a comprehensive reconstruction of the gene evolutionary history

2018 ◽  
Author(s):  
Sergey Y. Morozov ◽  
Irina A. Milyutina ◽  
Tatiana N. Erokhina ◽  
Liudmila V. Ozerova ◽  
Alexey V. Troitsky ◽  
...  
Keyword(s):  
Small Rnas ◽  
Evolutionary History ◽  
Common Ancestor ◽  
Land Plants ◽  
Specific Class ◽  
Small Interfering Rnas ◽  
Evolutionary Transition ◽  
Evolutionary Pathway ◽  
Regulate Gene Expression ◽  
Genomic Dnas

Trans-acting small interfering RNAs (ta-siRNAs) are transcribed from protein non-coding genomic loci and belong to a plant-specific class of endogenous small RNAs. These siRNAs have been found to regulate gene expression in most taxa including seed plants, gymnosperms, ferns and mosses. In this study, bioinformatic and experimental PCR-based approaches were used as tools to analyze TAS3 and TAS6 loci in transcriptomes and genomic DNAs from representatives of evolutionary distant Bryophyta, Marchantiophyta and Anthocerotophyta. We revealed previously undiscovered TAS3 loci in classes Sphagnopsida and Anthocerotopsida, as well as TAS6 loci in Bryophyta classes Tetraphidiopsida, Polytrichopsida, Andreaeopsida and Takakiopsida. These data further unveil the evolutionary pathway of the miR390-dependent TAS3 loci in land plants. We also identified SGS3-coding sequences in charophytes and hypothesized that the appearance of TAS3-related sequences could take place at a very early step in evolutionary transition from charophyte algae to an earliest common ancestor of land plants.

scholarly journals Spectrum of Camel Evolution and its Impact on Ancient Human Migration

2021 ◽  
Author(s):  
Indu Sharma ◽  
Jyotsna Sharma ◽  
Sachin Kumar ◽  
Hemender Singh ◽  
Varun Sharma ◽  
...  
Keyword(s):  
Evolutionary History ◽  
Migration Pattern ◽  
Human Migration ◽  
Genetic Affinity ◽  
The World ◽  
Silk Route ◽  
Bactrian Camels ◽  
Second Millennium Bce ◽  
And Migration ◽  
Different Parts

The Evolutionary history and domestication of Camels are largely unexplored because of the lack of well dated early archaeological records. However, limited records suggest that domestication of Camels likely happened in the late second millennium BCE. Over the time, camels have helped human for their basic needs like meat, milk, wool, dung to long routes transportation. This multifaceted animal has helped the mankind to connect through continents and in trade majorly through the Silk route. In India, both dromedary and Bactrian camels are found and their habitat is entirely different from each other, dromedaries inhabit in hot deserts and Bactrians are found mostly in cold places (Nubra Valley, Ladakh). Fewer studies on Indian dromedaries have been conducted but no such studies are done on Bactrian camels. It is needed to study the genetics of Bactrian camels to find out their genetic affinity and evolutionary history with other Bactrians found in different parts of the world. Furthermore, parallel studies on humans and Bactrian camel are required to understand the co-evolution and migration pattern of humans during their dispersal in different time periods.

scholarly journals Unlimited Associative Learning and the origins of consciousness: a primer and some predictions

2020 ◽  
Vol 35 (6) ◽  
Author(s):  
Jonathan Birch ◽  
Simona Ginsburg ◽  
Eva Jablonka
Keyword(s):  
Associative Learning ◽  
Evolutionary Transition ◽  
Central Idea ◽  
The Past ◽  
Evolutionary Origins ◽  
Novel Approach ◽  
Distinctive Type ◽  
Clear Statement

AbstractOver the past two decades, Ginsburg and Jablonka have developed a novel approach to studying the evolutionary origins of consciousness: the Unlimited Associative Learning (UAL) framework. The central idea is that there is a distinctive type of learning that can serve as a transition marker for the evolutionary transition from non-conscious to conscious life. The goal of this paper is to stimulate discussion of the framework by providing a primer on its key claims (Part I) and a clear statement of its main empirical predictions (Part II).

scholarly journals An African origin for Mycobacterium bovis

2020 ◽  
Vol 2020 (1) ◽  
pp. 49-59 ◽  
Author(s):  
Chloé Loiseau ◽  
Fabrizio Menardo ◽  
Abraham Aseffa ◽  
Elena Hailu ◽  
Balako Gumi ◽  
...  
Keyword(s):  
Population Structure ◽  
West Africa ◽  
Mycobacterium Bovis ◽  
Evolutionary History ◽  
Whole Genome ◽  
Genome Sequences ◽  
The World ◽  
History Of ◽  
Global Population ◽  
Different Parts

Abstract Background and objectives Mycobacterium bovis and Mycobacterium caprae are two of the most important agents of tuberculosis in livestock and the most important causes of zoonotic tuberculosis in humans. However, little is known about the global population structure, phylogeography and evolutionary history of these pathogens. Methodology We compiled a global collection of 3364 whole-genome sequences from M.bovis and M.caprae originating from 35 countries and inferred their phylogenetic relationships, geographic origins and age. Results Our results resolved the phylogenetic relationship among the four previously defined clonal complexes of M.bovis, and another eight newly described here. Our phylogeographic analysis showed that M.bovis likely originated in East Africa. While some groups remained restricted to East and West Africa, others have subsequently dispersed to different parts of the world. Conclusions and implications Our results allow a better understanding of the global population structure of M.bovis and its evolutionary history. This knowledge can be used to define better molecular markers for epidemiological investigations of M.bovis in settings where whole-genome sequencing cannot easily be implemented. Lay summary During the last few years, analyses of large globally representative collections of whole-genome sequences (WGS) from the human-adapted Mycobacterium tuberculosis complex (MTBC) lineages have enhanced our understanding of the global population structure, phylogeography and evolutionary history of these pathogens. In contrast, little corresponding data exists for M. bovis, the most important agent of tuberculosis in livestock. Using whole-genome sequences of globally distributed M. bovis isolates, we inferred the genetic relationships among different M. bovis genotypes distributed around the world. The most likely origin of M. bovis is East Africa according to our inferences. While some M. bovis groups remained restricted to East and West Africa, others have subsequently dispersed to different parts of the world driven by cattle movements.

scholarly journals hox gene expression predicts tetrapod-like axial regionalization in the skate, Leucoraja erinacea

2021 ◽  
Vol 118 (51) ◽  
pp. e2114563118
Author(s):  
Katharine E. Criswell ◽  
Lucy E. Roberts ◽  
Eve T. Koo ◽  
Jason J. Head ◽  
J. Andrew Gillis
Keyword(s):  
Gene Expression ◽  
Vertebral Column ◽  
Evolutionary History ◽  
Cell Lineage ◽  
Axial Skeleton ◽  
Lineage Tracing ◽  
Paraxial Mesoderm ◽  
Evolutionary Transition ◽  
Geometric Morphometric ◽  
Geometric Morphometric Analysis

The axial skeleton of tetrapods is organized into distinct anteroposterior regions of the vertebral column (cervical, trunk, sacral, and caudal), and transitions between these regions are determined by colinear anterior expression boundaries of Hox5/6, -9, -10, and -11 paralogy group genes within embryonic paraxial mesoderm. Fishes, conversely, exhibit little in the way of discrete axial regionalization, and this has led to scenarios of an origin of Hox-mediated axial skeletal complexity with the evolutionary transition to land in tetrapods. Here, combining geometric morphometric analysis of vertebral column morphology with cell lineage tracing of hox gene expression boundaries in developing embryos, we recover evidence of at least five distinct regions in the vertebral skeleton of a cartilaginous fish, the little skate (Leucoraja erinacea). We find that skate embryos exhibit tetrapod-like anteroposterior nesting of hox gene expression in their paraxial mesoderm, and we show that anterior expression boundaries of hox5/6, hox9, hox10, and hox11 paralogy group genes predict regional transitions in the differentiated skate axial skeleton. Our findings suggest that hox-based axial skeletal regionalization did not originate with tetrapods but rather has a much deeper evolutionary history than was previously appreciated.

The Birds from Las Hoyas

2002 ◽  
Vol 85 (2) ◽  
pp. 113-130 ◽  
Author(s):  
José Luis Sanz ◽  
Francisco Ortega
Keyword(s):  
Early Cretaceous ◽  
Evolutionary History ◽  
Morphological Changes ◽  
General View ◽  
Evolutionary Transition ◽  
Avian Flight ◽  
Theropod Dinosaurs ◽  
Fossil Material ◽  
Life Habits ◽  
Wing Aspect Ratio

Information on the first steps of the avian evolutionary history has dramatically increased during the last few years. The fossil record provides a general view of the morphological changes of the avian flight apparatus from non-volant ancestors (non-avian theropod dinosaurs) to the first derived fliers of the Early Cretaceous. The Las Hoyas bird record includes three genera: Iberomesornis, Concornis and Eoalulavis. This fossil material has yielded information about the early avian evolutionary history. These Early Cretaceous birds (some 120 Myr old) had a wingbeat cycle and breathing devices similar to those of extant birds. The function of the rectricial fan was also similar. In the evolutionary transition from cursorial ancestors to derived fliers it is possible to verify a trend to increase lift. Primitive wing aspect ratio morphotypes were elliptical ones, other derived morphotypes appeared, for example, in the Neornithes (extant birds). Some primitive fliers, like the Las Hoyas genus Eoalulavis, had an alula (feathers attached to the first digit of the hand) similar to that of present day birds, indicating braking and manoeuvring skills similar to those of their extant relatives. Primitive avian life habits are poorly understood. Some evidence from the Las Hoyas bird record indicates that Early Cretaceous birds were present in the trophic chains.

scholarly journals Superorganismal anisogamy: queen–male dimorphism in eusocial insects

2020 ◽  
Vol 287 (1928) ◽  
pp. 20200635
Author(s):  
Jussi Lehtonen ◽  
Heikki Helanterä
Keyword(s):  
Mathematical Model ◽  
Division Of Labour ◽  
Male Dimorphism ◽  
Theoretical Idea ◽  
Size Dimorphism ◽  
Eusocial Insects ◽  
Competition Theory ◽  
Male Gametes ◽  
Gamete Competition ◽  
Colony Survival

Colonies of insects such as ants and honeybees are commonly viewed as ‘superorganisms’, with division of labour between reproductive ‘germline-like’ queens and males and ‘somatic’ workers. On this view, properties of the superorganismal colony are comparable with those of solitary organisms to such an extent that the colony itself can be viewed as a unit analogous to an organism. Thus, the concept of a superorganism can be useful as a guide to thinking about life history and allocation traits of colonies as a whole. A pattern that seems to reoccur in insects with superorganismal societies is size dimorphism between queens and males, where queens tend to be larger than males. It has been proposed that this is analogous to the phenomenon of anisogamy at the level of gametes in organisms with separate sexes; more specifically, it is suggested that this caste dimorphism may have evolved via similar selection pressures as gamete dimorphism arises in the ‘gamete competition’ theory for the evolution of anisogamy. In this analogy, queens are analogous to female gametes, males are analogous to male gametes, and colony survival is analogous to zygote survival in gamete competition theory. Here, we explore if this question can be taken beyond an analogy, and whether a mathematical model at the superorganism level, analogous to gamete competition at the organism level, may explain the caste dimorphism seen in superorganismal insects. We find that the central theoretical idea holds, but that there are also significant differences between the way this generalized ‘propagule competition’ theory operates at the levels of solitary organisms and superorganisms. In particular, we find that the theory can explain superorganismal caste dimorphism, but compared with anisogamy evolution, a central coevolutionary link is broken, making the requirements for the theory to work less stringent than those found for the evolution of anisogamy.

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