Challenges in estimating ancestral state reconstructions: the evolution of migration in Sylvia warblers as a study case

2020 ◽  
Vol 15 (3) ◽  
pp. 161-173
Author(s):  
Raquel PONTI ◽  
Angel ARCONES ◽  
David R. VIEITES
Keyword(s):  
Ancestral State ◽  
Study Case ◽  
Evolution Of Migration

scholarly journals Migration and the evolution of sexual dichromatism: evolutionary loss of female coloration with migration among wood-warblers

2015 ◽  
Vol 282 (1809) ◽  
pp. 20150375 ◽  
Author(s):  
Richard K. Simpson ◽  
Michele A. Johnson ◽  
Troy G. Murphy
Keyword(s):  
Sexual Selection ◽  
Sexual Dichromatism ◽  
Ancestral State ◽  
Migration Distance ◽  
Female Ornamentation ◽  
Wood Warblers ◽  
Selection For ◽  
Evolution Of Migration ◽  
And Migration ◽  
Female Coloration

The mechanisms underlying evolutionary changes in sexual dimorphism have long been of interest to biologists. A striking gradient in sexual dichromatism exists among songbirds in North America, including the wood-warblers (Parulidae): males are generally more colourful than females at northern latitudes, while the sexes are similarly ornamented at lower latitudes. We use phylogenetically controlled comparative analysis to test three non-mutually exclusive hypotheses for the evolution of sexual dichromatism among wood-warblers. The first two hypotheses focus on the loss of female coloration with the evolution of migration, either owing to the costs imposed by visual predators during migration, or owing to the relaxation of selection for female social signalling at higher latitudes. The third hypothesis focuses on whether sexual dichromatism evolved owing to changes in male ornamentation as the strength of sexual selection increases with breeding latitude. To test these hypotheses, we compared sexual dichromatism to three variables: the presence of migration, migration distance, and breeding latitude. We found that the presence of migration and migration distance were both positively correlated with sexual dichromatism, but models including breeding latitude alone were not strongly supported. Ancestral state reconstruction supports the hypothesis that the ancestral wood-warblers were monochromatic, with both colourful males and females. Combined, these results are consistent with the hypotheses that the evolution of migration is associated with the relaxation of selection for social signalling among females and that there are increased predatory costs along longer migratory routes for colourful females. These results suggest that loss of female ornamentation can be a driver of sexual dichromatism and that social or natural selection may be a stronger contributor to variation in dichromatism than sexual selection.

scholarly journals Phylogeny, Historical Biogeography and the Evolution of Migration in Accipitrid Birds of Prey (Aves: Accipitriformes)

2014 ◽  
Vol 22 (1) ◽  
pp. 15-35 ◽  
Author(s):  
Jenő Nagy ◽  
Jácint Tökölyi
Keyword(s):  
Large Scale ◽  
Bird Species ◽  
Ecological Factors ◽  
Molecular Dating ◽  
Birds Of Prey ◽  
Tropical Species ◽  
Ancestral State ◽  
Biogeographic History ◽  
Ancestral Area Reconstruction ◽  
Evolution Of Migration

Abstract Migration plays a fundamental part in the life of most temperate bird species. The regular, large-scale seasonal movements that characterize temperate migration systems appear to have originated in parallel with the postglacial northern expansion of tropical species. Migratoriness is also influenced by a number of ecological factors, such as the ability to survive harsh winters. Hence, understanding the origins and evolution of migration requires integration of the biogeographic history and ecology of birds in a phylogenetic context. We used molecular dating and ancestral state reconstruction to infer the origins and evolutionary changes in migratory behavior and ancestral area reconstruction to investigate historical patterns of range evolution in accipitrid birds of prey (Accipitriformes). Migration evolved multiple times in birds of prey, the earliest of which occurred in true hawks (Accipitrinae), during the middle Miocene period, according to our analyses. In most cases, a tropical ancestral distribution was inferred for the non-migratory ancestors of migratory lineages. Results from directional evolutionary tests indicate that migration evolved in the tropics and then increased the rate of colonization of temperate habitats, suggesting that temperate species might be descendants of tropical ones that dispersed into these seasonal habitats. Finally, we found that diet generalization predicts migratoriness in this group.

Systematics, Biogeography, and Morphological Character Evolution of the Hemiepiphytic Subfamily Monsteroideae (Araceae)

2019 ◽  
Vol 104 (1) ◽  
pp. 33-48 ◽  
Author(s):  
Alejandro Zuluaga ◽  
Martin Llano ◽  
Ken Cameron
Keyword(s):  
Dna Sequences ◽  
Pacific Islands ◽  
R Package ◽  
Morphological Characters ◽  
Ancestral State ◽  
Seed Shape ◽  
Long Distance ◽  
The Pacific ◽  
And Migration ◽  
The Tropics

The subfamily Monsteroideae (Araceae) is the third richest clade in the family, with ca. 369 described species and ca. 700 estimated. It comprises mostly hemiepiphytic or epiphytic plants restricted to the tropics, with three intercontinental disjunctions. Using a dataset representing all 12 genera in Monsteroideae (126 taxa), and five plastid and two nuclear markers, we studied the systematics and historical biogeography of the group. We found high support for the monophyly of the three major clades (Spathiphylleae sister to Heteropsis Kunth and Rhaphidophora Hassk. clades), and for six of the genera within Monsteroideae. However, we found low rates of variation in the DNA sequences used and a lack of molecular markers suitable for species-level phylogenies in the group. We also performed ancestral state reconstruction of some morphological characters traditionally used for genera delimitation. Only seed shape and size, number of seeds, number of locules, and presence of endosperm showed utility in the classification of genera in Monsteroideae. We estimated ancestral ranges using a dispersal-extinction-cladogenesis model as implemented in the R package BioGeoBEARS and found evidence for a Gondwanan origin of the clade. One tropical disjunction (Monstera Adans. sister to Amydrium Schott–Epipremnum Schott) was found to be the product of a previous Boreotropical distribution. Two other disjunctions are more recent and likely due to long-distance dispersal: Spathiphyllum Schott (with Holochlamys Engl. nested within) represents a dispersal from South America to the Pacific Islands in Southeast Asia, and Rhaphidophora represents a dispersal from Asia to Africa. Future studies based on stronger phylogenetic reconstructions and complete morphological datasets are needed to explore the details of speciation and migration within and among areas in Asia.

THE PROFILE OF A LEADER AND HIS LEDERSHIP

2018 ◽  
Vol 28 (1) ◽  
pp. 345-350
Author(s):  
Ali Hajro
Keyword(s):  
Leadership Skills ◽  
Real Power ◽  
Governmental Organization ◽  
Factors Affecting ◽  
The Real ◽  
The Core ◽  
Behavior Code ◽  
The People ◽  
Study Case ◽  
Personal Skills

The Current and future leaders live in a turbulent and chaotic environment, where the real power of acting derives from the recognition of the concept of change and looking for options. In this type of environment a lot of competence is necessary for the leaders to survive. The aim of this study case was to explore i.e. gain a clearer picture of the position of the leader, their characteristics, functions, levels, the core and the factors affecting the leader and their leadership. To see what type of leader the people want simply to draw conclusions about the characteristics, qualities and techniques of a leader and their leadership. So that in the end, to have empirical proof of the leader. The set goal in this study case is today’s leaders in everyday process, starting from the very beginning of their work, to serve as an example in developing inter-personal skills at the same time as treating people with dignity and respect. In other words, they have to possess leadership skills, characteristics and the necessary actions. This research aims at finding out the real attributes that is the profile of a leader and their leadership running an organization regardless if it is economic, political, and military or some other non-governmental organization. The values are more than a set of rules, they are not only behavior code, and they say what a leader should be every day in every action that they take. The values shade the leaders’ identity and the organization that they run.

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