Macroecology and consilience

Consilience means that all fields of human knowledge should be internally consistent. Within the broad span of the ecological and evolutionary sciences, there are many fields that seem only remotely related conceptually. Macroecology has emerged as a research programme that focuses on statistical patterns of ecological and biogeographically relevant traits among different species within a taxon. The concepts needed to understand these patterns require the interface of disciplines as different as systematics, ecosystem ecology, palaeontology and community ecology. By building conceptual links among a wide range of disciplines, macroecology is contributing, and will continue to contribute, to the growing realization that all of biology is indeed consilient.     

Taxonomy and systematics of the genus Pinus based on morphological, biogeographical and biochemical characters

For a long time, systematists have subdivided the genus Pinus into Diploxylon and Haploxylon according to morpho-anatomy and the number of needles. Nevertheless, divergent views remain regarding the structure of these two subgenera, mainly at the section and subsection levels. We propose to clarify some of these uncertainties by studying 45 Pinus taxa of different origins. Our results, based on morphometric and biochemical (flavonoids) parameters, complement those obtained from classical anatomical and morphological studies, and also modern macro-molecular markers (proteins, DNA). We confirm the subdivision of the genus into Pinus = Diploxylon versus Strobus = Haploxylon and the further sectioning of the first subgenus into sections Pinus and Trifoliae. Moreover, we specify the different subsections, whereby the contents of the methylated flavonol isorhamnetin coupled with needle morphometry play a significant role (subsections Pinus vs. Pinaster in section Pinus, Australes + Ponderosae vs. Contortae in section Trifoliae). Given that isorhamnetin proceeds from quercetin by the irreversible action of an O-methyl-transferase, this methylated flavonol becomes a dynamic marker in such way that the taxa rich in isorhamnetin can be considered as more “derived = evolved”. In addition, there exists a highly significant negative correlation between methylation index and number of needles. Consequently, the pines from the Holarctic Strobus group (with five needles and low isorhamnetin contents) can be considered as “ancestral”, in reference to a Laurasian origin of the genus. In the subgenus Pinus, the Nearctic group (=section Trifoliae) remains near the ancestral base. On the other hand, the Holarctic subset “densiflorae” is connected to the other members (mainly European) of the polyphyletic subsection Pinus, in particular with series “sylvestres”. Because of their very high contents of isorhamnetin, the Mediterranean pines result from an accentuation of this evolutionary trend (=subsection Pinaster). In fact, the pines growing under hot and dry climates (Mediterranean region) are highly evolved compared to those from cold and/or wet regions (Eurasia and North America but also, to a lesser extent, the south-eastern USA and East Asia). Our dynamic propositions based on plant phenolics data complete those from more modern macromolecular (DNA, proteins) studies.     

Cluster analysis in biogeographical classifications

Some unavoidable methodic and methodological problems arising at each stage of the classification of objects by the methods of hierarchical clustering are shown on the concrete (biogeographical) and abstract--numerical examples. Reasons which cause these problems and possible ways of minimization of cluster analysis artifacts are discussed. Unavoidable constrains in interpretations of dendrograms obtained by means of agglomerate algorithms are indicated.     

Logic in systematics

Systematic biologists attempt to infer the taxonomic relationship of one species to another based on the available evidence. Phylogenetic systematists demand that these species relationships reflect evolutionary history (they expect their taxa to be monophyletic). Just exactly how this is to be achieved remains a subject of debate. There are many different kinds of evidence, and many different ways of inferring taxonomic relationships (plus evolutionary history) from them. In this paper, we argue that one such way of inferring species relationships, the hypothetico‐deductive method, proves a bad fit with phylogenetic systematics because it requires an excessively strong assumption of the relationship that obtains between hypotheses of descent and the available evidence.     

Traditional morphometrics in plant systematics and its role in palm systematics

A review is given of the role of traditional morphometrics in plant systematics. The three most commonly used techniques of data analysis – Cluster Analysis, Principal Component Analysis and Discriminant Analysis – are discussed. The kinds of data that can be taken from palm specimens and the problems of using specimens as data sources are outlined. Published systematic studies of palms using traditional morphometrics are reviewed. More recent studies indicate that: hybrid zones between species may be common; infraspecific diversity is greater than previously suspected; there may be more than double the currently accepted number of species; and our current knowledge of morphological variation in palms is superficial. A procedure for scientific systematics is given, which incorporates traditional morphometric methods.  © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society , 2006, 151 , 103–111.     

Post-Melting-Pot Realism

Neoliberalism, Transnationalization and Rural Poverty: A Case Study of Michoacán Mexico. John Gledhill. Boulder
American Dreaming: Immigrant Life on the Margins. Sarah Mahler. Princeton     

Grasses through space and time: An overview of the biogeographical and macroevolutionary history of Poaceae

Grasses are widespread on every continent and are found in all terrestrial biomes. The dominance and spread of grasses and grassland ecosystems have led to significant changes in Earth′s climate, geochemistry, and biodiversity. The abundance of DNA sequence data, particularly chloroplast sequences, and advances in placing grass fossils within the family allows for a reappraisal of the family′s origins, timing, and geographic spread and the factors that have promoted diversification. We reconstructed a time-calibrated grass phylogeny and inferred ancestral areas using chloroplast DNA sequences from nearly 90% of extant grass genera. With a few notable exceptions, the phylogeny is well resolved to the subtribal level. The family began to diversify in the Early–Late Cretaceous (crown age of 98.54 Ma) on West Gondwana before the complete split between Africa and South America. Vicariance from the splitting of Gondwana may be responsible for the initial divergence in the family. However, Africa clearly served as the center of origin for much of the early diversification of the family. With this phylogenetic, temporal, and spatial framework, we review the evolution and biogeography of the family with the aim to facilitate the testing of biogeographical hypotheses about its origins, evolutionary tempo, and diversification. The current classification of the family is discussed with an extensive review of the extant diversity and distribution of species, molecular and morphological evidence supporting the current classification scheme, and the evidence informing our understanding of the biogeographical history of the family.     

Problems in polychaete systematics

Some of the intriguing issues in current polychaete systematics are reviewed. (1) The root of the `polychaete' tree. Currently there are two major hypotheses concerning the root position among polychaetes. One is based on rooting cladograms with outgroups such as Mollusca and result in simple-bodied taxa such as Opheliidae and Questidae forming a basal annelid grade along with Clitellata. Other hypotheses do not use outgroup rooting but involve scenarios on the evolution of the group and would place taxa in Aciculata as basal annelids, thus making Aciculata and Phyllodocida paraphyletic. Molecular sequence data has been of little help in resolving this issue thus far, largely due to limited taxon sampling. (2) Paraphyly. Owing, in part, to a tradition involving the emphasis on differences among taxa, and the application of Linnean ranks (e.g., family), paraphyly is undoubtedly a widespread phenomenon in polychaete systematics. An example of this has been proposed already for Spionidae. If the tree topology and rooting used by Blake & Arnofsky (1999) is correct, Spionidae is made paraphyletic by the recognition of the following four family-ranked taxa; Trochochaetidae, Poecilochaetidae, Longosomatidae and Uncispionidae. Another possible example is seen with Cirratulidae. A preliminary cladistic analysis shows that it is entirely possible that seven other taxa recognised as families may be nested within Cirratulidae. These include Acrocirridae, Ctenodrilidae, Fauveliopsidae, Flabelligeridae, Flotidae, Poeobiidae and Sternaspidae. (3) Problematic taxa. Apart from the problems exposed by the analysis of Cirratuliformia, the position of some of these groups, such as Aberranta, Alciopidae, Hesionides,Lopadorhynchidae, Microphthalmus,Nerillidae, Spinther,Tomopteridae and Sabellariidae, is discussed.     

分子系统学研究进展

分子系统学 ( molecular systematics)是近 30年发展起来的一门综合性前沿学科 ,它在分子水平上对生物进行遗传多样性、分类、系统发育和进化等方面的研究 ,其研究结果对于保护生物多样性 (尤其是遗传多样性 ) ,揭示生物进化历程及机理具有十分重要的意义。1　分子系统学的定义及发展简史分子系统学是通过检测生物大分子包含的遗传信息 ,定量描述、分析这些信息在分类、系统发育和进化上的意义 ,从而在分子水平上解释生物的多样性、系统发育及进化规律的一门学科。它以分子生物学、系统学、遗传学、分类学和进化论为理论基础 ,以分子生物学…     

Molecular systematics

Journal of Molecular Evolution -