scholarly journals Spatial sorting as the spatial analogue of natural selection

2017 ◽  
Author(s):  
Ben L. Phillips ◽  
T. Alex Perkins
Keyword(s):  
Natural Selection ◽  
Habitat Quality ◽  
Rapid Evolution ◽  
General Mechanism ◽  
Dispersal Ability ◽  
Spatial Sorting ◽  
Temporal Aspects ◽  
Varying Environments ◽  
High Level ◽  
Dispersal Evolution

AbstractIn most systems, dispersal occurs despite clear fitness costs to dispersing individuals. Theory posits that spatial heterogeneity in habitat quality pushes dispersal rates to evolve towards zero, while temporal heterogeneity in habitat quality favours non-zero dispersal rates. One aspect of dispersal evolution that has received a great deal of recent attention is a process known as spatial sorting, which has been referred to as a “shy younger sibling” of natural selection. More precisely, spatial sorting is the process whereby variation in dispersal ability is sorted along density clines and will, in nature, often be a transient phenomenon. Despite this transience, spatial sorting is likely a general mechanism behind non-zero dispersal in spatiotemporally varying environments. While generally transient, spatial sorting is persistent on invasion fronts, where its effect cannot be ignored, causing rapid evolution of traits related to dispersal. Spatial sorting is described in several elegant models, yet these models require a high level of mathematical sophistication and are not accessible to most evolutionary biologists or their students. Here, we frame spatial sorting in terms of the classic haploid and diploid models of natural selection. We show that, on an invasion front, spatial sorting can be conceptualized precisely as selection operating through space rather than (as with natural selection) time, and that genotypes can be viewed as having both spatial and temporal aspects of fitness. The resultant model is strikingly similar to classic models of natural selection. This similarity renders the model easy to understand (and to teach), but also suggests that many established theoretical results around natural selection could apply equally to spatial sorting.

The effect of exposure to conspecifics on restlessness in the parasitoid wasp Nasonia vitripennis (Hymenoptera: Pteromalidae)

2007 ◽  
Vol 139 (5) ◽  
pp. 678-684 ◽  
Author(s):  
B.H. King
Keyword(s):  
Habitat Quality ◽  
Parasitoid Wasp ◽  
Poor Quality ◽  
The Other ◽  
Dispersal Ability ◽  
Nasonia Vitripennis ◽  
Adult Females ◽  
Selection For ◽  
The Difference ◽  
Abundance And Distribution

AbstractWhen habitat quality is variable, there should be strong selection for the ability to detect and respond to the variation. Adult females of the parasitoid wasp Nasonia vitripennis (Walker) are known to increase their restlessness (the proportion of time in locomotion) both during and after exposure to a poor quality host. Doing so provides a mechanism for leaving a poor host and potentially finding a better host. This study examined whether restlessness also changes in response to competition as indicated by the presence of adult conspecifics. Both restlessness and the probability of dispersing across an inhospitable environment were greater when a female was with another female than when she was alone. However, restlessness did not remain elevated after the other female was removed. In contrast with females, restlessness of males did not increase either during or after exposure to other males, and the probability of dispersing across an inhospitable environment was unaffected by the presence of another male. The difference between females and males may be related to differences in dispersal ability and in the abundance and distribution of hosts versus mates.

scholarly journals Physical interactions reduce the power of natural selection in growing yeast colonies

2018 ◽  
Vol 115 (45) ◽  
pp. 11448-11453 ◽  
Author(s):  
Andrea Giometto ◽  
David R. Nelson ◽  
Andrew W. Murray
Keyword(s):  
Natural Selection ◽  
Continuum Model ◽  
Microbial Populations ◽  
Mechanical Forces ◽  
Time Varying ◽  
Drug Resistant ◽  
Yeast Strains ◽  
Physical Interactions ◽  
Varying Environments ◽  
Doubling Times

Microbial populations often assemble in dense populations in which proliferating individuals exert mechanical forces on the nearby cells. Here, we use yeast strains whose doubling times depend differently on temperature to show that physical interactions among cells affect the competition between different genotypes in growing yeast colonies. Our experiments demonstrate that these physical interactions have two related effects: they cause the prolonged survival of slower-growing strains at the actively-growing frontier of the colony and cause faster-growing strains to increase their frequency more slowly than expected in the absence of physical interactions. These effects also promote the survival of slower-growing strains and the maintenance of genetic diversity in colonies grown in time-varying environments. A continuum model inspired by overdamped hydrodynamics reproduces the experiments and predicts that the strength of natural selection depends on the width of the actively growing layer at the colony frontier. We verify these predictions experimentally. The reduced power of natural selection observed here may favor the maintenance of drug-resistant cells in microbial populations and could explain the apparent neutrality of interclone competition within tumors.

Evolution theory and the future of humanity

2008 ◽  
Author(s):  
Christopher Wills
Keyword(s):  
Natural Selection ◽  
Communication Skills ◽  
Evolutionary Biology ◽  
Skin Pigmentation ◽  
Homo Erectus ◽  
Skin Colour ◽  
Evolution Theory ◽  
The Future ◽  
Genetic Level ◽  
High Level

No field of science has cast more light on both the past and the future of our species than evolutionary biology. Recently, the pace of new discoveries about how we have evolved has increased (Culotta and Pennisi, 2005). It is now clear that we are less unique than we used to think. Genetic and palaeontological evidence is now accumulating that hominids with a high level of intelligence, tool-making ability, and probably communication skills have evolved independently more than once. They evolved in Africa (our own ancestors), in Europe (the ancestors of the Neanderthals) and in Southeast Asia (the remarkable ‘hobbits’, who may be miniaturized and highly acculturated Homo erectus). It is also becoming clear that the genes that contribute to the characteristics of our species can be found and that the histories of these genes can be understood. Comparisons of entire genomes have shown that genes involved in brain function have evolved more quickly in hominids than in more distantly related primates. The genetic differences among human groups can now be investigated. Characters that we tend to think of as extremely important markers enabling us to distinguish among different human groups now turn out to be understandable at the genetic level, and their genetic history can be traced. Recently a single allelic difference between Europeans and Africans has been found (Lamason et al., 2005). This functional allelic difference accounts for about a third of the differences in skin pigmentation in these groups. Skin colour differences, in spite of the great importance they have assumed in human societies, are the result of natural selection acting on a small number of genes that are likely to have no effects beyond their influence on skin colour itself. How do these and other recent findings from fields ranging from palaeontology to molecular biology fit into present-day evolution theory, and what light do they cast on how our species is likely to evolve in the future? I will introduce this question by examining briefly how evolutionary change takes place.

Adaptable Ancestors

2020 ◽  
pp. 71-91
Author(s):  
David F. Bjorklund
Keyword(s):  
Natural Selection ◽  
Evolutionary Change ◽  
Behavioral Changes ◽  
Social Transmission ◽  
Significant Extent ◽  
Transmission Of Information ◽  
Selection Behavior ◽  
Novel Environments ◽  
High Level ◽  
Or Genes

The high level of plasticity shown by children today was also a feature of our forechildren. Experiences early in life can modify the morphology or behavior of an animal and result in new pressures that can be the focus of natural selection. Behavior, in fact, takes the lead in evolution, because it is more susceptible to change than morphology or genes. Most of the changes early in development, at least for mammals, were accomplished in the presence of mothers. To a significant extent, mothers are the environment for young mammals, making mothers the environment for evolutionary change. Significant behavioral changes in evolution are most likely to occur in large-brained animals, who are better able to deal with novel environments through innovation and social transmission of information than smaller-brained animals.

Business Networking

2011 ◽  
pp. 334-353 ◽  
Author(s):  
Claudia-Melania Chituc ◽  
Américo Lopes Azevedo
Keyword(s):  
Information And Communication Technologies ◽  
Business Processes ◽  
Rapid Evolution ◽  
Communication Technologies ◽  
Key Factors ◽  
Information And Communication ◽  
Business Networking ◽  
High Level ◽  
Technological Perspective ◽  
Networked Organizations

The rapid evolution of information and communication technologies, the changing client’s demands, and market conditions impelled enterprises to adapt their way of undertaking business, from traditional practices to e-business, and to participate in new forms of collaboration, such as networked organizations. In this context, standards, frameworks, technologies, and infrastructures supporting collaborative business, in a networked environment, become key factors in achieving environments with a desired high level of collaboration and inter- and intra-organization business processes alignment. The aim of this chapter is to underline the main issues, trends, and opportunities related to business integration from a technological perspective, analyzing and discussing the most relevant (existing and still under development) business integration reference models, frameworks, standards, technologies, and supporting infrastructures, and to briefly present relevant research projects in the area of business networking. A special emphasis is made on frameworks such as ebXML and RosettaNet, and the importance of papiNet, BPLE4WS, and freebXML is underlined. Challenges regarding self-forming networked organizations are also advanced.

Business Networking

2009 ◽  
pp. 91-108
Author(s):  
Claudia-Melania Chituc ◽  
Américo Lopes Azevedo
Keyword(s):  
Information And Communication Technologies ◽  
Business Processes ◽  
Rapid Evolution ◽  
Communication Technologies ◽  
Key Factors ◽  
Information And Communication ◽  
Business Networking ◽  
High Level ◽  
Technological Perspective ◽  
Networked Organizations

The rapid evolution of information and communication technologies, the changing client’s demands, and market conditions impelled enterprises to adapt their way of undertaking business, from traditional practices to e-business, and to participate in new forms of collaboration, such as networked organizations. In this context, standards, frameworks, technologies, and infrastructures supporting collaborative business, in a networked environment, become key factors in achieving environments with a desired high level of collaboration and inter- and intra-organization business processes alignment. The aim of this chapter is to underline the main issues, trends, and opportunities related to business integration from a technological perspective, analyzing and discussing the most relevant (existing and still under development) business integration reference models, frameworks, standards, technologies, and supporting infrastructures, and to briefly present relevant research projects in the area of business networking. A special emphasis is made on frameworks such as ebXML and RosettaNet, and the importance of papiNet, BPLE4WS, and freebXML is underlined. Challenges regarding self-forming networked organizations are also advanced.

scholarly journals Single-Parent Expression of Anti-sense RNA Contributes to Transcriptome Complementation in Maize Hybrid

2020 ◽  
Vol 11 ◽  
Author(s):  
Xiangbo Zhang ◽  
Yongwen Qi
Keyword(s):  
Histone H3 ◽  
Single Parent ◽  
General Mechanism ◽  
Rna Seq ◽  
High Level Expression ◽  
Maize Hybrid ◽  
Maize Hybrids ◽  
Leaf Tissues ◽  
Important Regulator ◽  
High Level

Anti-sense transcription is increasingly being recognized as an important regulator of gene expression. But the transcriptome complementation of anti-sense RNA in hybrid relative to their inbred parents was largely unknown. In this study, we profiled strand-specific RNA sequencing (RNA-seq) in a maize hybrid and its inbred parents (B73 and Mo17) in two tissues. More anti-sense transcripts were present in the hybrid compared with the parental lines. We detected 293 and 242 single-parent expression of anti-sense (SPEA) transcripts in maize immature ear and leaf tissues, respectively. There was little overlap of the SPEA transcripts between the two maize tissues. These results suggested that SPEA is a general mechanism that drives extensive complementation in maize hybrids. More importantly, extremely high-level expression of anti-sense transcripts was associated with low-level expression of the cognate sense transcript by reducing the level of histone H3 lysine 36 methylation (H3K36me3). In summary, these SPEA transcripts increased our knowledge about the transcriptomic complementation in hybrid.

scholarly journals A Contribution for Virtual Prototyping of Mechatronic Systems Based on Real-Time Distributed High Level Architecture

2011 ◽  
Vol 12 (1) ◽  
Author(s):  
H. J. Hadj-Amor ◽  
T. Soriano
Keyword(s):  
Real Time ◽  
Geometric Model ◽  
Virtual Prototyping ◽  
Rapid Evolution ◽  
Behavior Model ◽  
Hybrid Automata ◽  
Mechatronic Systems ◽  
Work Related ◽  
And Performance ◽  
High Level

Mechatronics is the integration of different sciences and techniques of mechanical engineering, automatic control, electronics, and informatics. The rapid evolution of the market competitors requires the reduction of development time of a product while increasing the quality and performance. It is, therefore, necessary to increase the efficiency of the design process. To meet this need, simulation and, especially, virtual prototyping have become a key technology. It is difficult to find simulation tools are able to analyze multidependent systems of different areas. However, an environment that allows a simulation integrating multidisciplinary mechatronic systems is necessary. This paper describes a method of design and simulation of mechatronic systems. First, we identify the behavior model and its associated 3D geometric model. The behavior model is seen as a dynamic hybrid system of two coupled hybrid automata (operative part and control part). Then, we present OpenMASK and OpenModelica simulators, the IEEE1516 standard HLA and work related to this distributed architecture for simulation. In a top-down approach, we present our method and experiments to integrate HLA functionalities in these simulators and to distribute the modeling elements of mechatronic systems. Also, we propose extensions to integrate real-time for interactive simulations. Finally, we apply our approach on a representative example of a mechatronic system.

scholarly journals Dispersal evolution diminishes the negative density dependence in dispersal

2020 ◽  
Author(s):  
Abhishek Mishra ◽  
Partha Pratim Chakraborty ◽  
Sutirth Dey
Keyword(s):  
Spatial Ecology ◽  
Local Population ◽  
Rapid Evolution ◽  
Spatial Spread ◽  
Dispersal Traits ◽  
Evolution Study ◽  
Negative Density Dependence ◽  
Ecological Importance ◽  
Dispersal Evolution

ABSTRACTIn many organisms, dispersal varies with the local population density. Such patterns of density-dependent dispersal (DDD) are expected to shape the dynamics, spatial spread and invasiveness of populations. Despite their ecological importance, empirical evidence for the evolution of DDD patterns remains extremely scarce. This is especially relevant because rapid evolution of dispersal traits has now been empirically confirmed in several taxa. Changes in DDD of dispersing populations could help clarify not only the role of DDD in dispersal evolution, but also the possible pattern of subsequent range expansion. Here, we investigate the relationship between dispersal evolution and DDD using a long-term experimental evolution study on Drosophila melanogaster. We compared the DDD patterns of four dispersal-selected populations and their non-selected controls. The control populations showed negative DDD, which was stronger in females than in males. In contrast, the dispersal-selected populations showed density-independent dispersal, where neither males nor females exhibited DDD. We compare our results with previous evolutionary predictions that focused largely on positive DDD, and highlight how the direction of evolutionary change depends on the initial DDD pattern of a population. Finally, we discuss the implications of DDD evolution for spatial ecology and evolution.

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