A molecular perspective on the early evolutionary history of birds
- 出版日期：2000.
- 页数：189 p. :
- 第一责任说明：Marcel van Tuinen.
- 分类号：a564 ; a541
- ISBN：0493070850(ebk.) :
MARC全文
62h0023809 20140523103751.0 cr un||||||||| 110414s2000 xx ||||f|||d||||||||eng | AAI9998447 0493070850(ebk.) : CNY371.35 NGL NGL NGL a564 ; a541 van Tuinen, Marcel. A molecular perspective on the early evolutionary history of birds [electronic resource] / Marcel van Tuinen. 2000. 189 p. : digital, PDF file. Source: Dissertation Abstracts International, Volume: 61-12, Section: B, page: 6273. ; Adviser: S. B. Hedges. Thesis (Ph.D.) -- The Pennsylvania State University, 2000. Most avian classifications are based on morphological studies that are troubled by a limited knowledge of character evolution, and biases in the fossil record. Because of these concerns, this thesis provides a molecular perspective on the early evolutionary history of modern birds. To test traditional phylogenetic, biogeographic, and temporal hypotheses, phylogenies were obtained from new mitochondrial and nuclear DNA sequences. Results show evidence for larger superordinal clusters as well as for ratite monophyly. Specifically, ratites and tinamous form one group (Paleognathae), distinct from all other birds (Neognathae). Within Neognathae, waterfowl and gamefowl form a lineage (Galloanserae) separate from all other birds (Neoaves). Analyses show that previous molecular evidence against a paleognath-neognath division from mitochondrial genome analyses is likely the result of insufficient taxon sampling. Phylogenetic relationships among paleognaths are discussed within a biogeographic and fossil framework, and an origin for ratites from either South America or Africa is proposed. The time estimates for the divergence of ratites and tinamous obtained from three molecular data sets (83 MYR) suggest a South American origin for all ratites and tinamous. The molecular clock estimates are internally calibrated by the Galliformes-Anseriformes divergence time of 90 MYR, which was estimated by performing rate tests on nuclear genes available in the molecular databases. The timescale implies that large fossil gaps exist for the early divergences within modern birds, that modern birds coexisted extensively with non-modern lineages in the Cretaceous, and that proposed rapid morphological rates to explain modern bird diversification are relaxed. In addition, the phylogeny of three enigmatic aquatic birds was investigated using new sequence and DNA hybridization data. The new data resolved a shoebill-pelican group, with the Hamerkop as closest relative to that group, and a sister group relationship of flamingos and grebes. The phylogeny of Shoebill and Hamerkop argues against the established monophyly of Pelecaniformes but is supported by alternative morphological evidence. The flamingo-grebe grouping is a case where molecular evidence disagrees entirely with known morphological evidence. Adaptive changes apparently have masked morphological evidence in support of this grouping. These phylogenetic results support extensive morphological convergence and divergence in aquatic bird evolution. Birds ; Birds, Fossil. ; Birds Evolution. ; Origin. The Pennsylvania State University. aCN bNGL http://pqdt.bjzhongke.com.cn/Detail.aspx?pid=RR77udgdVe0%3d NGL Bs739 rCNY371.35 ; h1 bs1105