scholarly journals Linking population-level and microevolutionary processes to understand speciation dynamics at the macroevolutionary scale

2021 ◽  
Author(s):  
Laura Alencar ◽  
Tiago Bosisio Quental
Keyword(s):  
Population Level ◽  
Theoretical Models ◽  
Intrinsic Properties ◽  
Diversification Rates ◽  
Apparent Inconsistency ◽  
Speciation Rates ◽  
Physical Barriers ◽  
Methodological Approaches ◽  
Taxonomic Groups ◽  
Mechanistic View

Although speciation dynamics have been described for several taxonomic groups in distinct geographic regions, most macroevolutionary studies still lack a detailed mechanistic view on how or why speciation rates change. To help partially fill this gap, we suggest that the interaction between the time taken by a species to geographically expand and the time populations take to evolve reproductive isolation should be considered when we are trying to understand macroevolutionary patterns. We introduce a simple conceptual index to guide our discussion on how demographic and microevolutionary processes might produce speciation dynamics at macroevolutionary scales. Our framework is developed under different scenarios: when speciation is mediated by geographical or resource-partitioning opportunities, and when diversity is limited or not. We also discuss how organismal intrinsic properties and different overall geographical settings can influence the tempo and mode of speciation. We argue that specific conditions observed at the micro-scale might produce a pulse in speciation rates even without a pulse in either climate or physical barriers. We also propose a hypothesis to reconcile the apparent inconsistency between speciation measured at the micro and macro scales and emphasize that diversification rates are better seen as an emergent property. We hope to bring the reader’s attention to interesting mechanisms to be further studied, to motivate the development of new theoretical models that connect micro and macroevolution, and to inspire new empirical and methodological approaches to more adequately investigate speciation dynamics either using neontological or paleontological data.

scholarly journals Linking population-level and microevolutionary processes to understand speciation dynamics at the macroevolutionary scale

2021 ◽  
Author(s):  
Laura Alencar ◽  
Tiago Quental
Keyword(s):  
Population Level ◽  
Theoretical Models ◽  
Intrinsic Properties ◽  
Diversification Rates ◽  
Apparent Inconsistency ◽  
Speciation Rates ◽  
Physical Barriers ◽  
Methodological Approaches ◽  
Taxonomic Groups ◽  
Mechanistic View

Although speciation dynamics have been described for several taxonomic groups in distinct geographic regions, most macroevolutionary studies still lack a detailed mechanistic view on how or why speciation rates change. To help to partially fill this gap, we suggest that the interaction between the time taken by a species to geographically expand and the time populations take to evolve reproductive isolation should be considered when we are trying to understand macroevolutionary patterns. We introduce a simple conceptual index to guide our discussion on how demographic and microevolutionary processes might produce speciation dynamics at macroevolutionary scales. Our framework is developed under different scenarios: when speciation is mediated by geographical or resource-partitioning opportunities, and when diversity is limited or not. We also discuss how organismal intrinsic properties and different overall geographical settings can influence the tempo and mode of speciation. We argue that specific conditions observed at the micro scale might produce a pulse in speciation rates even without a pulse in either climate or physical barriers. We also propose a hypothesis to reconcile the apparent inconsistency between speciation measured at the micro and macro scales, and emphasize that diversification rates are better seen as an emergent property. We hope to bring the reader’s attention to interesting mechanisms to be further studied, to motivate the development of new theoretical models that connect micro and macroevolution, and to inspire new empirical and methodological approaches to more adequately investigate speciation dynamics either using neontological or paleontological data.

scholarly journals Seed size and its rate of evolution correlate with species diversification across angiosperms

2016 ◽  
Author(s):  
J. Igea ◽  
E. F. Miller ◽  
A. S. T. Papadopulos ◽  
A. J. Tanentzap
Keyword(s):  
Seed Size ◽  
Large Scale ◽  
Seed Mass ◽  
Rate Of Change ◽  
Ecological Niches ◽  
Phenotypic Change ◽  
Diversification Rates ◽  
Angiosperm Phylogeny ◽  
Speciation Rates ◽  
Taxonomic Groups

AbstractSpecies diversity varies greatly across the different taxonomic groups that comprise the Tree of Life (ToL). This imbalance is particularly conspicuous within angiosperms, but is largely unexplained. Seed mass is one trait that may help clarify why some lineages diversify more than others because it confers adaptation to different environments, which can subsequently influence speciation and extinction. The rate at which seed mass changes across the angiosperm phylogeny may also be linked to diversification by increasing reproductive isolation and allowing access to novel ecological niches. However, the magnitude and direction of the association between seed mass and diversification has not been assessed across the angiosperm phylogeny. Here, we show that absolute seed size and the rate of change in seed size are both associated with variation in diversification rates. Based on the largest available angiosperm phylogenetic tree, we found that smaller-seeded plants had higher rates of diversification, possibly due to improved colonisation potential. The rate of phenotypic change in seed size was also strongly positively correlated with speciation rates, providing rare, large-scale evidence that rapid morphological change is associated with species divergence. Our study now reveals that variation in morphological traits and, importantly, the rate at which they evolve can contribute to explaining the extremely uneven distribution of diversity across the ToL.

On the role of enemies in divergence and diversification of prey: a review and synthesis

2005 ◽  
Vol 83 (7) ◽  
pp. 894-910 ◽  
Author(s):  
Steven M Vamosi
Keyword(s):  
Visual Cues ◽  
Phenotypic Diversity ◽  
Theoretical Models ◽  
Ecological Interactions ◽  
Closely Related Species ◽  
Diversification Rates ◽  
Extinction Rates ◽  
Phenotypic Divergence ◽  
Experimental Approaches

Understanding the contribution of ecological interactions to the origin and maintenance of diversity is a fundamental challenge for ecologists and evolutionary biologists, and one that is currently receiving a great deal of attention. Natural enemies (e.g., predators, parasites, and herbivores) are ubiquitous in food webs and are predicted to have significant impacts on phenotypic diversity and on speciation, and extinction rates of their prey. Spurred by the development of a theoretical framework beginning in the late 1970s, there is now a growing body of literature that addresses the effects of enemy–prey interactions on the evolution of prey. A number of theoretical models predict that enemies can produce phenotypic divergence between closely related species, even in the absence of interspecific competition for resources. Effects on diversification of prey are more variable, and enemies may either enhance or depress speciation and extinction rates of their prey. Empirical evidences from a number of study systems, notably those involving predators and prey in aquatic environments and interactions between insects and flowering plants, confirm both predictions. There is now considerable evidence for the role of enemies, especially those that are size-selective or use visual cues when identifying suitable prey, on phenotypic divergence of sympatric and allopatric taxa. Enemies may spur diversification rates in certain groups under some circumstances, and hinder diversification rates in other cases. I suggest that further research should focus on the role of enemies in diversification of prey, with significant insights likely to be the product of applying traditional experimental approaches and emerging comparative phylogenetic methods.

scholarly journals Evolutionary rates of mitochondrial genomes correspond to diversification rates and to contemporary species richness in birds and reptiles

2010 ◽  
Vol 277 (1700) ◽  
pp. 3587-3592 ◽  
Author(s):  
Soo Hyung Eo ◽  
J. Andrew DeWoody
Keyword(s):  
Species Richness ◽  
Nuclear Data ◽  
Synonymous Substitution ◽  
Evolutionary Rates ◽  
Rate Variation ◽  
Substitution Rates ◽  
Diversification Rates ◽  
Extinction Process ◽  
Molecular Evolutionary Rates ◽  
Speciation Rates

Rates of biological diversification should ultimately correspond to rates of genome evolution. Recent studies have compared diversification rates with phylogenetic branch lengths, but incomplete phylogenies hamper such analyses for many taxa. Herein, we use pairwise comparisons of confamilial sauropsid (bird and reptile) mitochondrial DNA (mtDNA) genome sequences to estimate substitution rates. These molecular evolutionary rates are considered in light of the age and species richness of each taxonomic family, using a random-walk speciation–extinction process to estimate rates of diversification. We find the molecular clock ticks at disparate rates in different families and at different genes. For example, evolutionary rates are relatively fast in snakes and lizards, intermediate in crocodilians and slow in turtles and birds. There was also rate variation across genes, where non-synonymous substitution rates were fastest at ATP8 and slowest at CO 3. Family-by-gene interactions were significant, indicating that local clocks vary substantially among sauropsids. Most importantly, we find evidence that mitochondrial genome evolutionary rates are positively correlated with speciation rates and with contemporary species richness. Nuclear sequences are poorly represented among reptiles, but the correlation between rates of molecular evolution and species diversification also extends to 18 avian nuclear genes we tested. Thus, the nuclear data buttress our mtDNA findings.

scholarly journals Behavioural adjustment of fish to temporal variation in fishing pressure affects catchability: an experiment with angled trout

2020 ◽  
Vol 77 (1) ◽  
pp. 188-193 ◽  
Author(s):  
Barbara Koeck ◽  
Magnus Lovén Wallerius ◽  
Robert Arlinghaus ◽  
Jörgen I. Johnsson
Keyword(s):  
Temporal Variation ◽  
Internal State ◽  
Empirical Support ◽  
Population Level ◽  
Theoretical Models ◽  
Fishing Effort ◽  
Threat Perception ◽  
Fishing Pressure ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Catch Rates

In passive fisheries, such as angling, the fishing success depends on the ultimate decision of a fish to ingest the bait, based on an individual’s internal state, previous experience, and threat perception. Fish surviving capture by anglers are known to be less vulnerable, and catch rates usually quickly decline with increasing fishing effort. Previous theoretical models have thus suggested fishing closures as a means to recover responsiveness of fish to angling gear and maintain catch rates, yet empirical support remains limited. In a controlled replicated pond experiment, we evaluated the effects of temporal variation in fishing pressure on catch rates of rainbow trout (Oncorhynchus mykiss) by simulating short-term fishing closures. Fishing closures increased catch rates and population-level catchability by reducing threat perception at the population level and allowing released individuals to return to a vulnerable state. Our experimental results show that periodic fishing closures benefit catch rates but at the risk of aggravating the likelihood of overharvesting.

Allocation of resources to sex functions in flowering plants

1991 ◽  
Vol 332 (1262) ◽  
pp. 91-102 ◽  
Keyword(s):  
Resource Allocation ◽  
Natural Selection ◽  
Population Level ◽  
Theoretical Models ◽  
Flowering Plants ◽  
Allocation Of Resources ◽  
Biological Reality ◽  
Theoretical Predictions ◽  
Allocation Patterns ◽  
Unisexual Flowers

The study of allocation of resources offers the possibility of understanding the pressures of natural selection on reproductive functions. In allocation studies, theoretical predictions are generated and the assumptions as well as the predictions can be tested in the field. Here, we review some of the theoretical models, and discuss how much biological reality can be included in them, and what factors have been left out. We also review the empirical data that have been generated as tests of this body of theory. There are many problems associated with estimating reproductive resources, and also with testing how allocation of these resources affects reproductive and other components of fitness, and we assess how important these may be in allowing empirical results to be interpreted. Finally, we discuss the relevance of resource allocation patterns to the evolution of unisexual flowers, both at the level of individual plants (monoecy, andro- and gynomonoecy) and at the population level (dioecy).

scholarly journals Polyploidy increases overall diversity despite higher turnover than diploids in the Brassicaceae

2019 ◽  
Author(s):  
Cristian Román-Palacios ◽  
Y. Franchesco Molina-Henao ◽  
Michael S. Barker
Keyword(s):  
Species Richness ◽  
Chromosome Numbers ◽  
Long Term Evolution ◽  
Tree Of Life ◽  
Evolutionary Significance ◽  
Diversification Rates ◽  
Diversity Patterns ◽  
Term Evolution ◽  
Speciation Rates

AbstractAlthough polyploidy, or whole-genome duplication, is widespread across the Plant Tree of Life, its long-term evolutionary significance is still poorly understood. Here we examine the effects of polyploidy in driving macroevolutionary patterns within the angiosperm family Brassicaceae, a speciose clade exhibiting extensive inter-specific variation in chromosome numbers. We inferred ploidal levels from haploid chromosome numbers for 80% of species in the most comprehensive species-level chronogram for the Brassicaceae published to date. After evaluating a total of 54 phylogenetic models of diversification, we found that ploidy drives diversification rates across the Brassicaceae, with polyploids experiencing faster rates of speciation and extinction, but relatively slower rates of diversification. Nevertheless, diversification rates are, on average, positive for both polyploids and diploids. We also found that despite diversifying significantly slower than diploids, polyploids have played a significant role in driving present-day differences in species richness among clades. Overall, although most polyploids go extinct before sustainable populations are established, rare successful polyploids persist and significantly contribute to the long-term evolution of lineages. Our findings suggest that polyploidy has played a major role in shaping the long-term evolution of the Brassicaceae and highlight the importance of polyploidy in shaping present-day diversity patterns across the plant Tree of Life.Significance statementAlthough polyploidy is a source of innovation, its long-term evolutionary significance is still debated. Here we analyze the evolutionary role of polyploidy within the Brassicaceae, a diverse clade exhibiting extensive variation in chromosome numbers among species. We found that, although polyploids diversify slower than diploids, polyploids have faster extinction and speciation rates. Our results also suggest that polyploidy has played an important role in shaping present-day differences in species richness within the Brassicaceae, with potential implications in explaining diversity patterns across the plant Tree of Life.

New Directions in Law and Literature

2017 ◽  
Keyword(s):  
Political Theory ◽  
Queer Theory ◽  
Theoretical Models ◽  
Copyright Law ◽  
Law And Literature ◽  
Law Schools ◽  
Affect Studies ◽  
New Directions ◽  
Methodological Approaches

After the heyday of the law and literature movement in the 1970s and 1980s, many wondered whether it would retain vitality and influence. Yet in recent years, scholarship in law and literature continues to flourish, broadening into a number of new directions. This collection of essays by twenty-two prominent scholars from literature departments as well as law schools showcases the vibrancy of recent work in the field, at the same time as it takes stock of many of the new directions shaping the interdiscipline. In so doing, New Directions in Law and Literature furnishes an overview of where the field has been, its recent past, and its potential futures. Some of the essays examine the innovative methodological approaches that helped to enlarge the field; among these are concern for globalization, the integration of insights from history and political theory, the application of new theoretical models from affect studies and queer theory, and the expansion of study beyond the text to performance and the image. Other essays instead grapple with particular intersections between law and literature, whether in copyright law, or competing visions of alternatives to marriage, or the role of ornament in the law’s construction of racialized bodies. Together, the essays in this volume offer a diverse, evolving portrait of the wide variety of work in law and literature, and in the process they likewise chart new lines of inquiry that beginning scholars might pursue.

The population dynamics of competition between parasites

Parasitology ◽  
1985 ◽  
Vol 91 (2) ◽  
pp. 317-347 ◽  
Author(s):  
A. P. Dobson
Keyword(s):  
Population Dynamics ◽  
Parasite Species ◽  
Interference Competition ◽  
Population Level ◽  
Experimental Tests ◽  
Theoretical Models ◽  
Control Agent ◽  
Host Population ◽  
Free Living ◽  
The Impact

A number of published studies of competition between parasite species are examined and compared. It is suggested that two general levels of interaction are discernible: these correspond to the two levels of competition recognized by workers studying free-living animals and plants: ‘exploitation’ and ‘interference’ competition. The former may be defined as the joint utilization of a host species by two or more parasite species, while the latter occurs when antagonistic mechanisms are utilized by one species either to reduce the survival or fecundity of a second species or to displace it from a preferred site of attachment. Data illustrating both levels of interaction are collated from a survey of the published literature and these suggest that interference competition invariably operates asymmetrically. The data are also used to estimate a number of population parameters which are important in determining the impact of competition at the population level. Theoretical models of host-parasite associations for both classes of competition are used to examine the expected patterns of population dynamics that will be exhibited by simple two-species communities of parasites that utilize the same host population. The analysis suggests that the most important factor allowing competing species of parasites to coexist is the statistical distribution of the parasites within the host population. A joint stable equilibrium should be possible if both species are aggregated in their distribution. The size of the parasite burdens at equilibrium is then determined by other life-history parameters such as pathogenicity, rates of resource utilization and antagonistic ability. Comparison of these theoretical expectations with a variety of sets of empirical data forms the basis for a discussion about the importance of competition in natural parasite populations. The models are used to assess quantitatively the potential for using competing parasite species as biological control agents for pathogens of economic or medical importance. The most important criterion for identifying a successful control agent is an ability to infect a high proportion of the host population. If such a parasite species also exhibits an intermediate level of pathology or an efficient ability to utilize shared common resources, antagonistic interactions between the parasite species contribute only secondarily to the success of the control. Competition in parasites is compared with competition in free-living animals and plants. The comparison suggests further experimental tests which may help to assess the importance of competition in determining the structure of more complex parasite-host communities.

Theoretical insights into single-atom catalysts

2020 ◽  
Vol 49 (22) ◽  
pp. 8156-8178 ◽  
Author(s):  
Lulu Li ◽  
Xin Chang ◽  
Xiaoyun Lin ◽  
Zhi-Jian Zhao ◽  
Jinlong Gong
Keyword(s):  
Theoretical Models ◽  
Single Atom ◽  
Schematic Diagram ◽  
Intrinsic Properties ◽  
Related Application

Schematic diagram of theoretical models and applications of single atom catalysts. A review on the theoretical models, intrinsic properties, and the related application of SACs.

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