219 research outputs found
A Reference Genome For The Nectar-Robbing Black-Throated Flowerpiercer (Diglossa Brunneiventris)
Black-throated Flowerpiercers (Diglossa brunneiventris) are one species representing a phenotypically specialized group of tanagers (Thraupidae) that have hooked bills which allow them to feed by stealing nectar from the base of flowers. Members of the genus are widely distributed in montane regions from Mexico to northern Argentina, and previous studies of Diglossa have focused on their systematics, phylogenetics, and interesting natural history. Despite numerous studies of species within the genus, no genome assembly exists to represent these nectivorous tanagers. We described the assembly of a genome sequence representing a museum-vouchered, wild, female D. brunneiventris collected in Peru. By combining Pacific Biosciences Sequel long-read technology with 10x linked-read and reference-based scaffolding, we produced a 1.08 Gbp pseudochromosomal assembly including 600 scaffolds with a scaffold N50 of 67.3 Mbp, a scaffold L50 of 6, and a BUSCO completeness score of 95%. This new assembly improves representation of the diverse species that comprise the tanagers, improves on scaffold lengths and contiguity when compared to existing genomic resources for tanagers, and provides another avenue of research into the genetic basis of adaptations common to a nectivorous lifestyle among vertebrates
Andean Land Use And Biodiversity: Humanized Landscapes In A Time Of Change
Some landscapes Cannot be understood without reference., to the kinds. degrees, kinds, degrees, and history of human-caused modifications to the Earth's surface. The tropical latitudes of the Andes represent one such place, with agricultural land-use systems appearing in the Early Holocene. Current land use includes both intensive and extensive grazing and crop- or tree-based agricultural systems found across virtually the, entire range of possible elevations and humidity regimes. Biodiversity found in or adjacent to such humanized landscapes will have been altered in abundance. composition, and distribution in relation to the resiliency of the native Species to harvest, hold cover modifications, and other deliberate or inadvertent human land uses. In addition, the geometries of land cover, resulting flout difference among the shapes, sizes, connectivities, and physical structures of the patches, corridors, and matrices that compose landscape mosaics, will constrain biodiversity, often in predictable ways. This article proposes a conceptual model that alter ins that the Continued persistence of native species may depend as much oil the shifting Of Andean landscape mosaics as on species characteristics, themselves. Furthermore, mountains such as the Andes display long gradients of environmental Conditions that after in relation to latitude, soil moisture, aspect, and elevation. Global environmental change will shift these, especially temperature and humidity regimes along elevational gradients, causing Changes outside the historical range of variation for some species. Both land-use systems and Conservation efforts will need to respond spatially to these shifts in the future, at both landscape and regional scales.Geography and the Environmen
Multiple Species And Deep Genomic Divergences Despite Little Phenotypic Differentiation In An Ancient Neotropical Songbird, Tunchiornis Ochraceiceps (Sclater, 1860) (Aves: Vireonidae)
Several bird taxa have been recently described or elevated to full species and almost twice as many bird species than are currently recognized may exist. Defining species is one of the most basic and important issues in biological science because unknown or poorly defined species hamper subsequent studies. Here, we evaluate the species limits and evolutionary history of Tunchiornis ochraceiceps-a widespread forest songbird that occurs in the lowlands of Central America, Choco and Amazonia-using an integrative approach that includes plumage coloration, morphometrics, vocalization and genomic data. The species has a relatively old crown age (similar to 9 Ma) and comprises several lineages with little, if any, evidence of gene flow among them. We propose a taxonomic arrangement composed of four species, three with a plumage coloration diagnosis and one deeply divergent cryptic species. Most of the remaining lineages have variable but unfixed phenotypic characters despite their relatively old origin. This decoupling of genomic and phenotypic differentiation reveals a remarkable case of phenotypic conservatism, possibly due to strict habitat association. Lineages are geographically delimited by the main Amazonian rivers and the Andes, a pattern observed in studies of other understory upland forest Neotropical birds, although phylogenetic relationships and divergence times among populations are idiosyncratic
A Comparison of the Tensile and Bending Properties of Dental Gold Wires
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68282/2/10.1177_00220345510300022001.pd
On the Theory of Evolution Versus the Concept of Evolution: Three Observations
Here we address three misconceptions stated by Rice et al. in their observations of our article Paz-y-Miño and Espinosa (Evo Edu Outreach 2:655–675, 2009), published in this journal. The five authors titled their note “The Theory of Evolution is Not an Explanation for the Origin of Life.” First, we argue that it is fallacious to believe that because the formulation of the theory of evolution, as conceived in the 1800s, did not include an explanation for the origin of life, nor of the universe, the concept of evolution would not allow us to hypothesize the possible beginnings of life and its connections to the cosmos. Not only Stanley Miller’s experiments of 1953 led scientists to envision a continuum from the inorganic world to the origin and diversification of life, but also Darwin’s own writings of 1871. Second, to dismiss the notion of Rice et al. that evolution does not provide explanations concerning the universe or the cosmos, we identify compelling scientific discussions on the topics: Zaikowski et al. (Evo Edu Outreach 1:65–73, 2008), Krauss (Evo Edu Outreach 3:193–197, 2010), Peretó et al. (Orig Life Evol Biosph 39:395–406, 2009) and Follmann and Brownson (Naturwissenschaften 96:1265–1292, 2009). Third, although we acknowledge that the term Darwinism may not be inclusive of all new discoveries in evolution, and also that creationists and Intelligent Designers hijack the term to portray evolution as ideology, we demonstrate that there is no statistical evidence suggesting that the word Darwinism interferes with public acceptance of evolution, nor does the inclusion of the origin of life or the universe within the concept of evolution. We examine the epistemological and empirical distinction between the theory of evolution and the concept of evolution and conclude that, although the distinction is important, it should not compromise scientific logic
The Apache Point Observatory Galactic Evolution Experiment (APOGEE) Spectrographs
We describe the design and performance of the near-infrared (1.51--1.70
micron), fiber-fed, multi-object (300 fibers), high resolution (R =
lambda/delta lambda ~ 22,500) spectrograph built for the Apache Point
Observatory Galactic Evolution Experiment (APOGEE). APOGEE is a survey of ~
10^5 red giant stars that systematically sampled all Milky Way populations
(bulge, disk, and halo) to study the Galaxy's chemical and kinematical history.
It was part of the Sloan Digital Sky Survey III (SDSS-III) from 2011 -- 2014
using the 2.5 m Sloan Foundation Telescope at Apache Point Observatory, New
Mexico. The APOGEE-2 survey is now using the spectrograph as part of SDSS-IV,
as well as a second spectrograph, a close copy of the first, operating at the
2.5 m du Pont Telescope at Las Campanas Observatory in Chile. Although several
fiber-fed, multi-object, high resolution spectrographs have been built for
visual wavelength spectroscopy, the APOGEE spectrograph is one of the first
such instruments built for observations in the near-infrared. The instrument's
successful development was enabled by several key innovations, including a
"gang connector" to allow simultaneous connections of 300 fibers; hermetically
sealed feedthroughs to allow fibers to pass through the cryostat wall
continuously; the first cryogenically deployed mosaic volume phase holographic
grating; and a large refractive camera that includes mono-crystalline silicon
and fused silica elements with diameters as large as ~ 400 mm. This paper
contains a comprehensive description of all aspects of the instrument including
the fiber system, optics and opto-mechanics, detector arrays, mechanics and
cryogenics, instrument control, calibration system, optical performance and
stability, lessons learned, and design changes for the second instrument.Comment: 81 pages, 67 figures, PASP, accepte
The Evolution Of A Tropical Biodiversity Hotspot
The tropics are the source of most biodiversity yet inadequate sampling obscures answers to fundamental questions about how this diversity evolves. We leveraged samples assembled over decades of fieldwork to study diversification of the largest tropical bird radiation, the suboscine passerines. Our phylogeny, estimated using data from 2389 genomic regions in 1940 individuals of 1287 species, reveals that peak suboscine species diversity in the Neotropics is not associated with high recent speciation rates but rather with the gradual accumulation of species over time. Paradoxically, the highest speciation rates are in lineages from regions with low species diversity, which are generally cold, dry, unstable environments. Our results reveal a model in which species are forming faster in environmental extremes but have accumulated in moderate environments to form tropical biodiversity hotspots
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