Pollination syndromes and the origins of floral traits.

Background: A general view in the study of pollination syndromes is that floral traits usually represent convergent floral adaptations to specific functional pollinator groups. However, the definition of convergence is elusive and contradictory in the literature. Is convergence the independent evolution of either the same trait or similar traits with the same function? A review of the concept of convergence in developmental biology and phylogenetic systematics may shed new light in studies of pollination syndromes.

A unified view of homology.

As it spread through time and into distinct areas of science-from comparative anatomy to evolutionary biology, cladistics, developmental and molecular biology-the homology concept has changed considerably, presenting various meanings. Despite many attempts at developing a comprehensive understanding of the concept, this context-sensitive notion of homology has been a subject of an ongoing debate. Inspired by that and following Kevin de Queiroz and Richard Mayden's view on species concept and delimitation, we presented in this article an attempt to systematize and advance the understanding of the homology problem.

Unbuttoning the Ancestral Flower of Angiosperms.

A recent study using an extensive data set plus sophisticated analytical tools reconstructed a model of the ancestral angiosperm flower. Although attractive, it presents problems of homology assessment. We discuss its inconsistencies and endorse the use of a comparative model that integrates biological parameters as essential to elucidate floral evolution.

The semaphorontic view of homology.

The relation of homology is generally characterized as an identity relation, or alternatively as a correspondence relation, both of which are transitive. We use the example of the ontogenetic development and evolutionary origin of the gnathostome jaw to discuss identity and transitivity of the homology relation under the transformationist and emergentist paradigms respectively. Token identity and consequent transitivity of homology relations are shown to be requirements that are too strong to allow the origin of genuine evolutionary novelties.

Homology assessment in parsimony and model-based analyses: two sides of the same coin.

The present paper is mainly concerned with homology assessment through phylogenetic analyses. It raises a fundamental question: What are the epistemological differences between modern parsimony and model-based analyses in relation to homology assessment and phylogenetic inference? Although these methods usually achieve concordant topological results, they may generate discordant inferences of character evolution from the same datasets. This indicates that method selection has serious implications for evolutionary scenarios and classificatory arrangements.

Does counting species count as taxonomy? On misrepresenting systematics, yet again.

Recent commentary by Costello and collaborators on the current state of the global taxonomic enterprise attempts to demonstrate that taxonomy is not in decline as feared by taxonomists, but rather is increasing by virtue of the rate at which new species are formally named. Having supported their views with data that clearly indicate as much, Costello et al. make recommendations to increase the rate of new species descriptions even more.

Are monophyly and synapomorphy the same or different? Revisiting the role of morphology in phylogenetics.

Species are groups of organisms, marked out by reproductive (replicative) properties. Monophyletic taxa are groups of species, marked out by synapomorphies. In Nelson's analysis, monophyly and synapomorphy are identical relations.

Coherence, correspondence, and the renaissance of morphology in phylogenetic systematics.

The decline in morphological phylogenies has become a pronounced trend in contemporary systematics due to a disregard for theoretical, methodological, conceptual, and philosophical approaches. The role and meaning of morphology in phylogenetic reconstruction and classification have been undermined by the following: (i) the ambiguous delineation of morphological characters; (ii) the putative "objectivity" of molecular data; (iii) that morphology has not been included in data matrices; (iv) that morphology has been mapped onto molecular cladograms; and (v) a separation of a paradigmatic relationship among morphology, phylogeny, and classification. Historical/philosophical arguments including the synthesis of coherence (coherentism) and correspondence (foundationalism) theories-i.