نتایج جستجو برای: taxa
تعداد نتایج: 30725 فیلتر نتایج به سال:
BACKGROUND The arthropod class Diplopoda is a mega-diverse group comprising >12,000 described millipede species. The history of taxonomic research within the group is tumultuous and, consequently, has yielded a questionable higher-level classification. Few higher-taxa are defined using synapomorphies, and the practice of single taxon descriptions lacking a revisionary framework has produced man...
a totall of 500 early permian samples from the chal-i-sheh formation in the zagros basin were examined palynollogically in order to determine the stratigraphical age of the formation and to assess the palaeogeopaphicd relatianships of this basin to the southern and northern hemispheres during the early permian. fifty-eight taxa were recorded including 46 pollen, 10 spore and 2 acritarch species...
sorkhankol wildlife refuge with an area of 1209 ha is located in the central part of anzali wetland. in total, 81 species belonging to 35 families and 68 genera were surveyed and identified on the basis of a floristic study from july 2013 through june 2014. the largest families are poaceae (11 taxa), asteraceae (8 taxa) apiaceae, brassicaceae and cyperacae (5 taxa). the dominant life forms were...
Recent studies have shown that addition or deletion of taxa from a data matrix can change the estimate of phylogeny. I used 29 data sets from the literature to examine the effect of taxon sampling on phylogeny estimation within data sets. I then used multiple regression to assess the effect of number of taxa, number of characters, homoplasy, strength of support, and tree symmetry on the sensiti...
Network models of soil and plant microbiomes provide new opportunities for enhancing disease management, but also challenges for interpretation. We present a framework for interpreting microbiome networks, illustrating how observed network structures can be used to generate testable hypotheses about candidate microbes affecting plant health. The framework includes four types of network analyses...
The human gut harbors thousands of bacterial taxa. A profusion of metagenomic sequence data has been generated from human stool samples in the last few years, raising the question of whether more taxa remain to be identified. We assessed metagenomic data generated by the Human Microbiome Project Consortium to determine if novel taxa remain to be discovered in stool samples from healthy individu...
From a Darwinian point of view, taxonomic groups are understood as historical entities that arise at an evolutionary moment and that can always disappear. But these groups were also understood by many naturalists as natural kinds; in other words, as permanent, ahistorical types. I will explore some of the forms that this typological thought took, showing that this typological perspective neithe...
704 American Journal of Botany 98(4): 704–730, 2011; http://www.amjbot.org/ © 2011 Botanical Society of America 1 Manuscript received 11 October 2010; revision accepted 9 February 2011. The authors thank the University of Florida High-Performance Computing Center, the UF Genetics Institute, and facilities supported in part by NSF Grant CNS-0821622 for providing computational resources that faci...
Persistent difficulties in resolving clear lineages in diverging populations of prokaryotes or unicellular eukaryotes (protistan polyphyletic groups) are challenging the classical species concept. Although multiple integrated approaches would render holistic taxonomies, most phylogenetic studies are still based on single-gene or morphological traits. Such methodologies conceal natural lineages,...
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