scholarly journals Recent Evolutionary History of the Fox Sparrows (Genus: Passerella)

The Auk ◽  
2003 ◽  
Vol 120 (2) ◽  
pp. 522-527
Author(s):  
Robert M. Zink ◽  
Jason D. Weckstein
Keyword(s):  
Control Region ◽  
Evolutionary History ◽  
Biological Species ◽  
Biological Species Concept ◽  
Base Pairs ◽  
Dna Variation ◽  
As Species ◽  
History Of ◽  
Passerella Iliaca ◽  
And Control

Abstract On the basis of plumage coloration and mitochondrial DNA variation, four main groups are recognized within the Fox Sparrow (Passerella iliaca): the red group (iliaca, RE), sooty group (unalaschcensis, SO), thick-billed (megarhyncha, TB), and slate-colored (schistacea, SC). To establish phylogenetic relationships among those four groups, we analyzed 2119 base pairs of sequence from four mitochondrial regions: ND2, ND3, cytochrome b, and control region. The control region is less variable than the coding genes surveyed. Both maximum parsimony and maximum likelihood resolved the same ingroup relationships (RE(SC(TB,SO))). However, placement of the root could not be established, even with four outgroups. Lack of resolution of the root is due to the nearest living relative of the Fox Sparrow being over 11% divergent. Despite lacking a clear root, the data suggest that the two taxa connected by a hybrid zone (TB, SC) are not sister species, which has implications for species limits because under the biological species concept they should be lumped. We recommend that all four main groups be recognized as species.

Species

2018 ◽  
Author(s):  
Kim Sterelny
Keyword(s):  
Homo Sapiens ◽  
Evolutionary Process ◽  
Biological Species ◽  
Biological Species Concept ◽  
Temporal Perspective ◽  
As Species ◽  
History Of ◽  
Diversity Of Life ◽  
Species Taxon ◽  
Species Definitions

The diversity of life is not seamless but comes in relatively discrete packages, species. Is that packaging real, or an artefact of our limited temporal perspective on the history of life? If all living forms are descended from one or a few ancestors, there may be no real distinction between living and ancestral forms, or between closely related living animals. Received wisdom holds that species are the ’units of evolution’, for it is they that evolve. They are the upshot of evolutionary processes, but, if species and not just their component organisms compete with one another, they are also important agents in the evolutionary process. If so, species are real units in nature, not arbitrary segmentations of seamless variation. The ’species problem’ has been approached from two angles. One focus has been on specific taxa of the tree of life. What would settle whether some arbitrarily chosen organism is a member of homo sapiens or canis familiaris? This is sometimes known as the ’species taxon’ problem. An alternate way of approaching diversity has been to ask what all species have in common. What do all the populations we think of as species share? This is the ’species category’ problem. One idea is to group organisms into species by appealing to the overall similarity. This ’phenetic’ conception is in retreat. Most contemporary species definitions are relational, the animals that compose pan troglodytes are a species, not because they are all very similar (they are very like the pygmy chimps as well) but because of their relations amongst themselves and with their ancestors. The most famous relational definition is the ’biological species concept’, according to which conspecific organisms are organisms that can interbreed, however different they look. Relational species definitions aim to define a category of theoretical and explanatory interest to evolutionary and ecological theory. Given that there are many explanatory interests, one problem in evaluating these accounts is to determine whether they are genuinely rivals.

Biogeography and taxonomy of racket-tail hummingbirds (Aves: Trochilidae: Ocreatus): evidence for species delimitation from morphology and display behavior

Zootaxa ◽  
2016 ◽  
Vol 4200 (1) ◽  
pp. 83 ◽  
Author(s):  
KARL-L. SCHUCHMANN ◽  
ANDRÉ-A. WELLER ◽  
DIETMAR JÜRGENS
Keyword(s):  
Geographic Variation ◽  
Endemic Species ◽  
Species Delimitation ◽  
Evolutionary History ◽  
Species Concept ◽  
Molecular Data ◽  
Biological Species ◽  
Biological Species Concept ◽  
Taxonomic History ◽  
History Of

We analyzed geographic variation, biogeography, and intrageneric relationships of racket-tail hummingbirds Ocreatus (Aves, Trochilidae). Presently, the genus is usually considered monospecific, with O. underwoodii including eight subspecies (polystictus, discifer, underwoodii, incommodus, melanantherus, peruanus, annae, addae), although up to three species have been recognized by some authors. In order to evaluate the current taxonomy we studied geographic variation in coloration, mensural characters, and behavioral data of all Ocreatus taxa. We briefly review the taxonomic history of the genus. Applying the Biological Species Concept, species delimitation was based on a qualitative-quantitative criteria analysis including an evaluation of character states. Our results indicate that the genus should be considered a superspecies with four species, the monotypic Ocreatus addae, O. annae, and O. peruanus, and the polytypic O. underwoodii (including the subspecies underwoodii, discifer, incommodus, melanantherus, polystictus). In this taxonomic treatment, O. annae becomes an endemic species to Peru and O. addae is endemic to Bolivia. We recommend additional sampling of distributional, ethological, and molecular data for an improved resolution of the evolutionary history of Ocreatus. 

Discriminating arboviral species

2021 ◽  
Vol 102 (4) ◽  
Author(s):  
Yiyuan Li ◽  
Angela C. O’Donnell ◽  
Howard Ochman
Keyword(s):  
Evolutionary History ◽  
Viral Vectors ◽  
Species Concept ◽  
International Committee ◽  
Biological Species ◽  
Biological Species Concept ◽  
Substantial Variation ◽  
Artificial Boundaries ◽  
Human Infections

Mosquito-borne arboviruses, including a diverse array of alphaviruses and flaviviruses, lead to hundreds of millions of human infections each year. Current methods for species-level classification of arboviruses adhere to guidelines prescribed by the International Committee on Taxonomy of Viruses (ICTV), and generally apply a polyphasic approach that might include information about viral vectors, hosts, geographical distribution, antigenicity, levels of DNA similarity, disease association and/or ecological characteristics. However, there is substantial variation in the criteria used to define viral species, which can lead to the establishment of artificial boundaries between species and inconsistencies when inferring their relatedness, variation and evolutionary history. In this study, we apply a single, uniform principle – that underlying the Biological Species Concept (BSC) – to define biological species of arboviruses based on recombination between genomes. Given that few recombination events have been documented in arboviruses, we investigate the incidence of recombination within and among major arboviral groups using an approach based on the ratio of homoplastic sites (recombinant alleles) to non-homoplastic sites (vertically transmitted alleles). This approach supports many ICTV-designations but also recognizes several cases in which a named species comprises multiple biological species. These findings demonstrate that this metric may be applied to all lifeforms, including viruses, and lead to more consistent and accurate delineation of viral species.

scholarly journals Phylogeography of the California Thrasher (Toxostoma Redivivum) Based on Nested-Clade Analysis of Mitochondrial-DNA Variation

The Auk ◽  
2003 ◽  
Vol 120 (2) ◽  
pp. 346-361
Author(s):  
Erik A. Sgariglia ◽  
Kevin J. Burns
Keyword(s):  
Mitochondrial Dna ◽  
Range Expansion ◽  
Evolutionary History ◽  
Isolation By Distance ◽  
Nested Clade Analysis ◽  
Dna Variation ◽  
History Of ◽  
Past Fragmentation ◽  
Intraspecific Relationships ◽  
Geologic Data

Abstract Distribution of genealogical lineages within a species is likely the result of a complicated series of ecological and historical events. Nested-clade analysis is specifically designed as an objective phylogeographic approach for inferring evolutionary processes on a spatial and temporal scale for small subclades within a larger set of intraspecific relationships. Here, we use nested-clade analysis as well as other phylogeographic methods to investigate the evolutionary history of California Thrasher (Toxostoma redivivum) populations. Inferences resulting from nested clade analysis suggest a history that includes past fragmentation, range expansion, and isolation-by-distance. Along with root information, those inferences enable the construction of a biogeographic scenario for this species involving general southern ancestry, an early north–south division, northward range expansion, and a southward back-expansion into an already populated southern region. Isolation-by-distance is also identified, particularly in southern California, indicating that gene flow between localities does occur but is restricted. Many conclusions drawn from this study are concordant with geologic data as well as phylogeographic scenarios drawn for other codistributed California taxa.

scholarly journals Evolutionary history of Nile perch Lates sp. inferred from mitochondrial DNA variation analyses

2013 ◽  
Vol 52 (1) ◽  
Author(s):  
Matthew Tenywa Mwanja ◽  
Vincent Muwanika ◽  
Charles Masembe ◽  
Sylvester Nyakaana ◽  
Wilson Waiswa Mwanja
Keyword(s):  
Mitochondrial Dna ◽  
Evolutionary History ◽  
Nile Perch ◽  
Dna Variation ◽  
History Of

scholarly journals Morphological ghosts of introgression in Darwin’s finch populations

2021 ◽  
Vol 118 (31) ◽  
pp. e2107434118
Author(s):  
Peter R. Grant ◽  
B. Rosemary Grant
Keyword(s):  
Evolutionary History ◽  
Genomic Data ◽  
Evolutionary Divergence ◽  
Gene Exchange ◽  
Future Evolution ◽  
Large Form ◽  
Large Samples ◽  
As Species ◽  
History Of ◽  
Geospiza Fortis

Many species of plants, animals, and microorganisms exchange genes well after the point of evolutionary divergence at which taxonomists recognize them as species. Genomes contain signatures of past gene exchange and, in some cases, they reveal a legacy of lineages that no longer exist. But genomic data are not available for many organisms, and particularly problematic for reconstructing and interpreting evolutionary history are communities that have been depleted by extinctions. For these, morphology may substitute for genes, as exemplified by the history of Darwin’s finches on the Galápagos islands of Floreana and San Cristóbal. Darwin and companions collected seven specimens of a uniquely large form of Geospiza magnirostris in 1835. The populations became extinct in the next few decades, partly due to destruction of Opuntia cactus by introduced goats, whereas Geospiza fortis has persisted to the present. We used measurements of large samples of G. fortis collected for museums in the period 1891 to 1906 to test for unusually large variances and skewed distributions of beak and body size resulting from introgression. We found strong evidence of hybridization on Floreana but not on San Cristóbal. The skew is in the direction of the absent G. magnirostris. We estimate introgression influenced 6% of the frequency distribution that was eroded by selection after G. magnirostris became extinct on these islands. The genetic residuum of an extinct species in an extant one has implications for its future evolution, as well as for a conservation program of reintroductions in extinction-depleted communities.

scholarly journals Molecular Systematics and the Role of The “Várzea”–“Terra-Firme” Ecotone in the Diversification of Xiphorhynchus Woodcreepers (Aves: Dendrocolaptidae)

The Auk ◽  
2002 ◽  
Vol 119 (3) ◽  
pp. 621-640 ◽  
Author(s):  
Alexandre Aleixo
Keyword(s):  
Strong Support ◽  
Sequence Divergence ◽  
Decisive Role ◽  
Biological Species ◽  
Habitat Specialization ◽  
Terra Firme ◽  
Sister Relationship ◽  
As Species ◽  
History Of ◽  
Distinct Lineage

Abstract The phylogeny of all known Xiphorhynchus (Dendrocolaptidae) species and many of its subspecies was reconstructed to evaluate species limits in this taxonomically challenging genus and investigate the possible role played by the Amazonian “várzea” (floodplain forest)–“terra-firme” (upland forest) ecotone in its diversification. Phylogenies were inferred based on 2,430 bp of the mitochondrial DNA genes ND2, ND3, and cytochrome b. All phylogeny estimates supported the monophyly of all extant Xiphorhynchus species to the exclusion of the sibling species pair Straight-billed (X. picus) and Zimmer's (X. kienerii) woodcreeper. Confirming findings of previous molecular and anatomical studies, strong support was found to include the Lesser Woodcreeper (Lepidocolaptes fuscus) in Xiphorhynchus. Levels of sequence divergence among some subspecies of Buff-throated (X. guttatus), Ocellated (X. ocellatus), and Spix's (X. spixii) woodcreepers reached or exceeded those found between closely related, undisputed biological species of Xiphorhynchus. High levels of sequence differentiation and the paraphyly of some Xiphorhynchus species indicated that the following taxa should be recognized as species: Lafresnaye's (X. guttatoides), Tschudi's (X. chunchotambo), and Elegant (X. elegans) woodcreepers. All Xiphorhynchus species restricted to terra-firme forest in lowland Amazonia formed a well supported monophyletic group, whereas species restricted to várzea forest were either basal to a clade containing species found in a wide variety of habitats (Striped Woodcreeper [X. obsoletus]) or belonged to a distinct lineage likely to be regarded as a separate genus (X. kienerii). These findings falsified an anticipated sister relationship between várzea and terra-firme species, as expected if the várzea–terra-firme ecotone had played a decisive role in population differentiation and speciation within Xiphorhynchus. Instead, phylogeny estimates suggested that the várzea–terra-firme habitat specialization evolved early on in the evolutionary history of Xiphorhynchus and that subsequent differentiation occurred mostly within the terra-firme habitat.

scholarly journals Untangling systematics of the Paramacrobiotus areolatus species complex by an integrative redescription of the nominal species for the group, with multilocus phylogeny and species delineation in the genus Paramacrobiotus

2020 ◽  
Vol 188 (3) ◽  
pp. 694-716 ◽  
Author(s):  
Daniel Stec ◽  
Łukasz Krzywański ◽  
Krzysztof Zawierucha ◽  
Łukasz Michalczyk
Keyword(s):  
Dna Sequences ◽  
Integrative Taxonomy ◽  
Genetic Distances ◽  
Biological Species ◽  
Biological Species Concept ◽  
Nominal Species ◽  
Species Delineation ◽  
F1 Hybrid ◽  
Complex Species ◽  
History Of

Abstract Incomplete descriptions of nominal taxa are one of the most significant obstacles in modern taxonomy, including the taxonomy of Tardigrada. Another major problem in tardigrade systematics is the lack of tests for the reliability of genetic markers in species delineation. Here, we employ an integrative taxonomy approach to redescribe the nominal taxon for the P. areolatus complex, Paramacrobiotus areolatus. Moreover, we obtained multilocus DNA sequences for another 16 populations representing 9–12 Paramacrobiotus species collected from Europe, North America, Africa and Australia, enabling us to reconstruct the most extensive phylogeny of the genus to date. The identification of a pair of potentially cryptic dioecious P. areolatus complex species with divergent genetic distances in ITS2 (1.4%) and COI (13.8%) provided an opportunity to test the biological species concept for the first time in the history of tardigrade taxonomy. Intra- and interpopulation crosses did not differ in reproductive success in terms of F1 offspring. However, because of the low F1 family sizes, we were unfortunately unable to test F1 hybrid fertility. Although our results are only partially conclusive, they offer a baseline not only for further taxonomic and phylogenetic research on the areolatus complex, but also for studies on species delineation in tardigrades in general.

Sign in / Sign up

Export Citation Format

Share Document