scholarly journals Allopatric speciation is more prevalent than parapatric ecological divergence in tropical montane systems (Asteraceae: Piofontia)

2019 ◽  
Author(s):  
Oscar M. Vargas ◽  
Beryl B. Simpson
Keyword(s):  
Plant Diversity ◽  
Evolutionary Biology ◽  
Alternative Hypothesis ◽  
Species Distributions ◽  
Ecological Speciation ◽  
Allopatric Speciation ◽  
Ecological Divergence ◽  
Ongoing Debate ◽  
Diversification Rates ◽  
Formal Test

ABSTRACTElucidating how species accumulate in diversity hotspots is an ongoing debate in evolutionary biology. The páramo, in the Northern Andes, has remarkable high indices of plant diversity, endemicity, and diversification rates. A hypothesis for explaining such indices is that allopatric speciation is high in the páramo given its island-like distribution; an alternative hypothesis is that the altitudinal gradients of the Andean topography provides a variety of niches that drive vertical parapatric ecological speciation. A formal test for evaluating the relative roles of allopatric speciation and parapatric ecological divergence has not been carried out. The main aim of our study is to test which kind of speciation is more common in the páramo. We developed a framework incorporating phylogenetics, species’ distributions, and a morpho-ecological trait (leaf area) to compare sister species and infer whether allopatry or parapatric ecological divergence caused their speciation. We applied our framework to the species-rich genus Piofontia (63 spp.) and found that the majority of speciation events in Piofontia, (80%) have been driven by allopatric speciation events, while a smaller fraction (13%) are attributed to parapatric ecological divergence; one event produced inconclusive results (7%). We conclude that páramo autochthonous diversification is primarily driven by allopatric speciation.

scholarly journals Testing Host-Plant Driven Speciation in Phytophagous Insects: A Phylogenetic Perspective

2019 ◽  
Author(s):  
Emmanuelle Jousselin ◽  
Marianne Elias
Keyword(s):  
Host Plant ◽  
Evolutionary Biology ◽  
Phylogenetic Analyses ◽  
Evolutionary Process ◽  
Niche Differentiation ◽  
Ecological Speciation ◽  
Model Systems ◽  
Phytophagous Insects ◽  
Ecological Specialization ◽  
Recent Developments

During the last two decades, ecological speciation has been a major research theme in evolutionary biology. Ecological speciation occurs when reproductive isolation between populations evolves as a result of niche differentiation. Phytophagous insects represent model systems for the study of this evolutionary process. The host-plants on which these insects feed and often spend parts of their life cycle constitute ideal agents of divergent selection for these organisms. Adaptation to feeding on different host-plant species can potentially lead to ecological specialization of populations and subsequent speciation. This process is thought to have given birth to the astonishing diversity of phytophagous insects and is often put forward in macroevolutionary scenarios of insect diversification. Consequently, numerous phylogenetic studies on phytophagous insects have aimed at testing whether speciation driven by host-plant adaptation is the main pathway for the diversification of the groups under investigation. The increasing availability of comprehensive and well-resolved phylogenies and the recent developments in phylogenetic comparative methods are offering an unprecedented opportunity to test hypotheses on insect diversification at a macroevolutionary scale, in a robust phylogenetic framework. Our purpose here is to review the contribution of phylogenetic analyses to investigate the importance of plant-mediated speciation in the diversification of phytophagous insects and to present suggestions for future developments in this field.

Orogeny, sympatry and emergence of a new genus of Alpine subterranean Trechini (Coleoptera: Carabidae)

2019 ◽  
Vol 189 (4) ◽  
pp. 1217-1231
Author(s):  
Teo Delić ◽  
Andrej Kapla ◽  
Andrea Colla
Keyword(s):  
New Genus ◽  
Ecological Speciation ◽  
Beetle Species ◽  
Ecological Divergence ◽  
Ecological Differentiation ◽  
Morphological Diversification

Abstract Despite two centuries of research in European subterranean habitats, which resulted in descriptions of numerous obligate subterranean beetle species, the role of ecological differentiation in speciation of subterranean beetles remains understudied. Discovery of a new genus and a species of Alpine subterranean Trechini beetles, Petraphaenops unguiculatus gen. & sp. nov., enables us to question the reasons for its morphological and ecological divergence. Multilocus, time-calibrated phylogeny and extensive morphological analyses were used to place the evolution of the species in a temporal and palaeogeographical framework. Set within the phylogeny of Alpine Trechini, the new genus is shown to have split from its sister-genus, Aphaenopidius, by the end of the Pliocene. The timeline of the split between these closely related genera corresponds to the onset of major orogenetic events in the southern Calcareous Alps. The orogeny dynamics, coupled with simultaneous diversification of subterranean habitats, presumably initiated ecological speciation and morphological diversification of this highly troglomorphic subterranean trechine genus.

scholarly journals Rapid action in the Palaeogene, the relationship between phenotypic and taxonomic diversification in Coenozoic mammals

2013 ◽  
Vol 280 (1750) ◽  
pp. 20122244 ◽  
Author(s):  
P. Raia ◽  
F. Carotenuto ◽  
F. Passaro ◽  
P. Piras ◽  
D. Fulgione ◽  
...  
Keyword(s):  
Body Size ◽  
Resource Utilization ◽  
Evolutionary Biology ◽  
Species Level ◽  
Phenotypic Evolution ◽  
Diversification Rates ◽  
Rapid Action ◽  
Hierarchic Level ◽  
The Relationship ◽  
Size Estimates

A classic question in evolutionary biology concerns the tempo and mode of lineage evolution. Considered variously in relation to resource utilization, intrinsic constraints or hierarchic level, the question of how evolutionary change occurs in general has continued to draw the attention of the field for over a century and a half. Here we use the largest species-level phylogeny of Coenozoic fossil mammals (1031 species) ever assembled and their body size estimates, to show that body size and taxonomic diversification rates declined from the origin of placentals towards the present, and very probably correlate to each other. These findings suggest that morphological and taxic diversifications of mammals occurred hierarchically, with major shifts in body size coinciding with the birth of large clades, followed by taxonomic diversification within these newly formed clades. As the clades expanded, rates of taxonomic diversification proceeded independently of phenotypic evolution. Such a dynamic is consistent with the idea, central to the Modern Synthesis, that mammals radiated adaptively, with the filling of adaptive zones following the radiation.

scholarly journals Aphantasia, imagination and dreaming

2020 ◽  
Author(s):  
Cecily M. K. Whiteley
Keyword(s):  
Mental Imagery ◽  
Visual Imagery ◽  
Alternative Hypothesis ◽  
Ongoing Debate

Abstract Aphantasia is a recently discovered disorder characterised by the total incapacity to generate visual forms of mental imagery. This paper proposes that aphantasia raises important theoretical concerns for the ongoing debate in the philosophy and science of consciousness over the nature of dreams. Recent studies of aphantasia and its neurobehavioral correlates reveal that the majority of aphantasics, whilst unable to produce visual imagery while awake, nevertheless retain the capacity to experience rich visual dreams. This finding constitutes a novel explanandum for theories of dreaming. Specifically, I argue that the recent dream reports of aphantasics constitute an empirical challenge to the emerging family of views which claim that dreams are essentially imaginative experiences, constitutively involving the kinds of mental imagery which aphantasics, ex-hypothesi, lack. After presenting this challenge in the context of Jonathan Ichikawa’s recent arguments for this view, I argue that this empirical challenge may be overcome if the imagination theorist abandons Ichikawa’s account of dreaming in favour of a modified version. This involves the claim that dreams are essentially inactive and constitutively involve non voluntary forms of imagination. I conclude with a suggestion for further research which can test the viability of this alternative hypothesis, and move the debate forward.

scholarly journals Expansion in geographical and morphological space drives continued lineage diversification in a global passerine radiation

2018 ◽  
Vol 285 (1893) ◽  
pp. 20182181 ◽  
Author(s):  
Jonathan D. Kennedy ◽  
Michael K. Borregaard ◽  
Petter Z. Marki ◽  
Antonin Machac ◽  
Jon Fjeldså ◽  
...  
Keyword(s):  
Strong Predictor ◽  
Limited Range ◽  
Morphological Divergence ◽  
Unresolved Issue ◽  
Ecological Divergence ◽  
Diversification Rates ◽  
Large Numbers ◽  
Range Overlap ◽  
The Relationship ◽  
Lineage Diversification

Why diversification rates vary so extensively across the tree of life remains an important yet unresolved issue in biology. Two prominent and potentially independent factors proposed to explain these trends reflect the capacity of lineages to expand into new areas of (i) geographical or (ii) ecological space. Here, we present the first global assessment of how diversification rates vary as a consequence of geographical and ecological expansion, studying these trends among 15 speciose passerine families (together approximately 750 species) using phylogenetic path analysis. We find that relative slowdowns in diversification rates characterize families that have accumulated large numbers of co-occurring species (at the 1° scale) within restricted geographical areas. Conversely, more constant diversification through time is prevalent among families in which species show limited range overlap. Relative co-occurrence is itself also a strong predictor of ecological divergence (here approximated by morphological divergence among species); however, once the relationship between co-occurrence and diversification rates have been accounted for, increased ecological divergence is an additional explanatory factor accounting for why some lineages continue to diversify towards the present. We conclude that opportunities for prolonged diversification are predominantly determined by continued geographical range expansion and to a lesser degree by ecological divergence among lineages.

scholarly journals Phylogenetic tests for evolutionary innovation: the problematic link between key innovations and exceptional diversification

2017 ◽  
Vol 372 (1735) ◽  
pp. 20160417 ◽  
Author(s):  
Daniel L. Rabosky
Keyword(s):  
Information Content ◽  
Evolutionary Biology ◽  
Phylogenetic Trees ◽  
Diversification Rates ◽  
Evolutionary Innovation ◽  
Key Innovation ◽  
Branching Patterns ◽  
Lineage Diversification ◽  
Key Innovations ◽  
Adaptive Zone

Evolutionary innovation contributes to the spectacular diversity of species and phenotypes across the tree of life. ‘Key innovations’ are widely operationalized within evolutionary biology as traits that facilitate increased diversification rates, such that lineages bearing the traits ultimately contain more species than closely related lineages lacking the focal trait. In this article, I briefly review the inference, analysis and interpretation of evolutionary innovation on phylogenetic trees. I argue that differential rates of lineage diversification should not be used as the basis for key innovation tests, despite the statistical tractability of such approaches. Under traditional interpretations of the macroevolutionary ‘adaptive zone’, we should not necessarily expect key innovations to confer faster diversification rates upon lineages that possess them relative to their extant sister clades. I suggest that a key innovation is a trait that allows a lineage to interact with the environment in a fundamentally different way and which, as a result, increases the total diversification—but not necessarily the diversification rate—of the parent clade. Considered alone, branching patterns in phylogenetic trees are poorly suited to the inference of evolutionary innovation due to their inherently low information content with respect to the processes that produce them. However, phylogenies may be important for identifying transformational shifts in ecological and morphological space that are characteristic of innovation at the macroevolutionary scale. This article is part of the themed issue ‘Process and pattern in innovations from cells to societies’.

scholarly journals Quantifying the effects of anagenetic and cladogenetic evolution

2014 ◽  
Author(s):  
Krzysztof Bartoszek
Keyword(s):  
Generating Functions ◽  
Evolutionary Biology ◽  
General Framework ◽  
Common Ancestor ◽  
Recent Common Ancestor ◽  
Phenotypic Change ◽  
Type I ◽  
Ongoing Debate ◽  
Most Recent Common Ancestor ◽  
Types Of Change

An ongoing debate in evolutionary biology is whether phenotypic change occurs predominantly around the time of speciation or whether it instead accumulates gradually over time. In this work I propose a general framework incorporating both types of change, quantify the effects of speciational change via the correlation between species and attribute the proportion of change to each type. I discuss results of parameter estimation of Hominoid body size in this light. I derive mathematical formulae related to this problem, the probability generating functions of the number of speciation events along a randomly drawn lineage and from the most recent common ancestor of two randomly chosen tip species for a conditioned Yule tree. Additionally I obtain in closed form the variance of the distance from the root to the most recent common ancestor of two randomly chosen tip species.

scholarly journals Testing Host-Plant Driven Speciation in Phytophagous Insects: A Phylogenetic Perspective

2019 ◽  
Author(s):  
Emmanuelle Jousselin ◽  
Marianne Elias
Keyword(s):  
Host Plant ◽  
Evolutionary Biology ◽  
Phylogenetic Analyses ◽  
Evolutionary Process ◽  
Niche Differentiation ◽  
Ecological Speciation ◽  
Model Systems ◽  
Phytophagous Insects ◽  
Ecological Specialization ◽  
Recent Developments

During the last two decades, ecological speciation has been a major research theme in evolutionary biology. Ecological speciation occurs when reproductive isolation between populations evolves as a result of niche differentiation. Phytophagous insects represent model systems for the study of this evolutionary process. The host-plants on which these insects feed and often spend parts of their life cycle constitute ideal agents of divergent selection for these organisms. Adaptation to feeding on different host-plant species can potentially lead to ecological specialization of populations and subsequent speciation. This process is thought to have given birth to the astonishing diversity of phytophagous insects and is often put forward in macroevolutionary scenarios of insect diversification. Consequently, numerous phylogenetic studies on phytophagous insects have aimed at testing whether speciation driven by host-plant adaptation is the main pathway for the diversification of the groups under investigation. The increasing availability of comprehensive and well-resolved phylogenies and the recent developments in phylogenetic comparative methods are offering an unprecedented opportunity to test hypotheses on insect diversification at a macroevolutionary scale, in a robust phylogenetic framework. Our purpose here is to review the contribution of phylogenetic analyses to investigate the importance of plant-mediated speciation in the diversification of phytophagous insects and to present suggestions for future developments in this field.

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