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Journal

1997

Phylogeny

Articles 1 - 3 of 3

Full-Text Articles in Life Sciences

Phylogeny Of Polemoniaceae Based On Nuclear Ribosomal Internal Transcribed Spacer Dna Sequences, J. Mark Porter Jan 1997

Phylogeny Of Polemoniaceae Based On Nuclear Ribosomal Internal Transcribed Spacer Dna Sequences, J. Mark Porter

Aliso: A Journal of Systematic and Floristic Botany

Nuclear ribosomal internal transcribed spacer (ITS) DNA sequences are used to estimate the phylogeny of 53 members of Polemoniaceae, representing all but two genera of the family. Fitch parsimony analysis of equal-weighted nucleotide sites result in 1080 minimal-length trees. However, when alignment-ambiguous positions are removed and an II: 10 transition to transversion weighting is imposed only eight trees are found. These data are used to address two issues: I) patterns of diversification in Polemoniaceae, and 2) the circumscription and monophyly of the genus Gilia. Although the monophyly of Polemoniaceae is well supported, relationships inferred among the earliest diverging lineages are ...


Classification: More Than Just Branching Patterns Of Evolution, Tod F. Stuessy Jan 1997

Classification: More Than Just Branching Patterns Of Evolution, Tod F. Stuessy

Aliso: A Journal of Systematic and Floristic Botany

The past 35 years in biological systematics have been a time of remarkable philosophical and methodological developments. For nearly a century after Darwin's Origin of Species, systematists worked to understand the diversity of nature based on evolutionary relationships. Numerous concepts were presented and elaborated upon, such as homology, parallelism, divergence, primitiveness and advancedness, cladogenesis and anagenesis. Classifications were based solidly on phylogenetic concepts; they were avowedly monophyletic. Phenetics emphasized the immense challenges represented by phylogeny reconstruction and advised against basing classifications upon it. Pheneticists forced reevaluation of all previous classificatory efforts, and objectivity and repeatability in both grouping ...


The Linnaean Hierarchy And The Evolutionization Of Taxonomy, With Emphasis On The Problem Of Nomenclature, Kevin De Queiroz Jan 1997

The Linnaean Hierarchy And The Evolutionization Of Taxonomy, With Emphasis On The Problem Of Nomenclature, Kevin De Queiroz

Aliso: A Journal of Systematic and Floristic Botany

During the post-Darwinian history of taxonomy, the Linnaean hierarchy has maintained its role as a means for representing hierarchical taxonomic relationships. During the same period, the principle of descent has taken on an increasingly important role as the basis for reformulated versions of fundamental taxonomic concepts and principles. Early in this history, the principle of descent provided an explanation for the existence of taxa and implied a nested, hierarchical structure for taxonomic relationships. Although an evolutionary explanation for taxa contradicted the Aristotelian context within which the Linnaean hierarchy was developed, the nested, hierarchical structure of taxonomic rela· tionships implied by ...