Information in morphological characters

The construction of morphological character matrices is central to paleontological systematic study, which extracts paleontological information from fossils. Although the word information has been repeatedly mentioned in a wide array of paleontological systematic studies, its meaning has rarely been clarified nor specifically defined. It is important, however, to establish a standard to measure paleontological information because fossils are hardly complete, rendering the recognition of homologous and homoplastic structures difficult. Here, based on information theory, we show the deep connections between paleontological systematic study and communication system engineering. Information is defined as the decrease of uncertainty and it is the information in morphological characters that allows distinguishing operational taxonomic units (OTUs) and reconstructing evolutionary history. We propose that concepts in communication system engineering such as source coding and channel coding, correspond to the construction of diagnostic features and the entire character matrices in paleontological studies. The two coding strategies should be distinguished following typical communication system engineering, because they serve dual purposes. With character matrices from six different vertebrate groups, we analyzed their information properties including source entropy, mutual information, and channel capacity. Estimation of channel capacity shows character saturation of all matrices in transmitting paleontological information, indicating that, due to the presence of noise, oversampling characters not only increases the burden in character scoring, but also may decrease quality of matrices. We further test the use of information entropy, which measures how informative a variable is, as a character weighting criterion in parsimony‐based systematic studies. The results show high consistency with existing knowledge with both good resolution and interpretability.     

Diversity of functional morphological explanation

An introduction to the 19th Lochmühle conference on Architecture in living structure, organized by P. Dullemeijer, W.F. Gutmann and G.A. Zweers, held from March 15–17, 1984 in the Aussenstelle des Forschungsinstituts Senckenberg der Senckenbergischen Naturforschenden Gesellschaft, Frankfurt am Main.     

Intestinal occlusion: morphological features

In this research we studied the possible relationships between the level and the distribution of peroxidase-catalase activity and the degree of the morphological changes in the intestinal wall during mechanical occlusion. These researches have really proved that the increase of the peroxidase-catalase enzymes correlate proportionally with the damage of intestinal wall.     

Fluorescent morphological probe for hyaluronate

Hyaluronate levels change dramatically during morphogenesis of various tissues and organs. Morphological detection of the exact temporal and spatial distribution patterns of hyaluronate may help to elucidate its role in morphogenesis. Since no specific direct method for visualizing hyaluronate with the light or electron microscope is currently available, we have developed a morphological probe by exploiting the high-affinity interaction of cartilage proteoglycan with hyaluronate. The core protein of this proteoglycan consists of a region that binds specifically to hyaluronate with a high association constant, and a region to which the majority of sulfated polysaccharide chains are covalently attached. The polysaccharide chains were removed by treatment with chondroitinase ABC, and the core protein, labeled with rhodamine, was used as the probe. This fluorescent probe binds reversibly and specifically to [3H]hyaluronate in a binding assay using ammonium sulfate precipitation of the core protein. The probe has been used to visualize the cell surface hyaluronate of rat fibrosarcoma cells, 3T3 cells, and SV-40 transformed 3T3 cells, three cell types with significantly different amounts of cell surface-associated hyaluronate.     

Intestinal ischemia: morphological features--II

Superoxide radicals produced during acute intestinal ischemia are biochemically related with the presence of hydrogen peroxyde. In this study we have investigated the distribution of peroxidase-catalase activity, histochemically determined, in the ischemic ileal wall. In the rat, complete arterial and venous occlusion produced a progressive increase in extra-vascular peroxidase-catalase activity with a maximum corresponding to the ileal wall. Probably the tissue peroxidase-catalase activity is related to massive degranulation of polymorphonucleates.     

Some morphological observations on osteoclasts

Summary Osteoclasts of the peripheral portions of the endocranial aspect of young rat parietal and frontal bones were studied by scanning electron microscopy of glutaraldehyde fixed, critical point dried specimens. These studies show Osteoclasts to have a much more complicated form than has previously been realised. Extensively branching, elongated, smooth-surfaced cells, which are for the most part elevated above the level of the surrounding bone matrix surface and sometimes above portions of osteoblasts or other osteoclasts, were identified as motile non-resorbing cells. Portions of the former and other entire cells may be embowered in Howship's lacunae, have microvilli on their dorsal surface, and are surrounded by a serrated border of microprojections which have an apparently firm attachment to the matrix surface. Osteoclasts in short term culture show additional free surface ruffles which are not encountered in specimens taken fresh from the animal. No evidence of recruitment of osteoblasts or osteocytes into osteoclasts was found. Disinterred osteocytes retained an ability to migrate from their lacunae on to surrounding bone matrix surface.We would like to thank Elaine Maconnachie for expert technical assistance and Dr. Martin J. Evans for the use of his tissue culture laboratory. These studies have been supported in part by a grant from the Medical Research Council     

Computational locality in morphological maps

This paper presents a computational investigation of a range of morphological operations. These operations are first represented as morphological maps, or functions that take a stem as input and return an output with the operation applied (e.g., the ing-suffixation map takes the input ‘d???k’ and returns ‘d???k+??’). Given such representations, each operation can be classified in terms of the computational complexity needed to map a given input to its correct output. The set of operations analyzed includes various types of affixation, reduplication, and non-concatenative morphology. The results indicate that many of these operations require less than the power of regular relations (i.e., they are subregular functions), the exception being total reduplication. A comparison of the maps that fall into different complexity classes raises important questions for our overall understanding of the computational nature of phonology, morphology, and the morpho-phonological interface.     

Principal parts and morphological typology

Like the numbers in a sudoku puzzle, a lexeme’s principal parts provide enough information–but only enough–to deduce all of the remaining forms in its paradigm. Because principal parts are a distillation of the implicative relations that exist among the members of a lexeme’s paradigm, they afford an important (but heretofore neglected) basis for typological classification. We recognize three logically distinct sorts of principal-part systems that might be postulated for a given language: static, adaptive, and dynamic. Focussing for present purposes on dynamic systems, we propose five crosscutting criteria for the typological classification of principal-part systems. These criteria relate to (i) how many principal parts are needed to determine a lexeme’s paradigm; (ii) whether distinct lexemes possess parallel sets of principal parts; (iii) how many principal parts are needed to determine a given word in a lexeme’s paradigm; (iv) what sort of morphological relation exists between a principal part and the forms that it is used to deduce; and (v) whether lexemes’ nonprincipal parts are inferred from their principal parts in the same way from one inflection class to another. Drawing on these criteria, we propose a novel classification of a range of typologically diverse languages.     

Stochastic mapping of morphological characters

Many questions in evolutionary biology are best addressed by comparing traits in different species. Often such studies involve mapping characters on phylogenetic trees. Mapping characters on trees allows the nature, number, and timing of the transformations to be identified. The parsimony method is the only method available for mapping morphological characters on phylogenies. Although the parsimony method often makes reasonable reconstructions of the history of a character, it has a number of limitations. These limitations include the inability to consider more than a single change along a branch on a tree and the uncoupling of evolutionary time from amount of character change. We extended a method described by Nielsen (2002, Syst. Biol. 51:729-739) to the mapping of morphological characters under continuous-time Markov models and demonstrate here the utility of the method for mapping characters on trees and for identifying character correlation.     

Associations between heterozygosity and morphological variance

Recent studies have contrasted the expression of phenotypic traits, such as variance in morphological characters, with levels of genetic variation (heterozygosity) as determined by electrophoretic analysis of protein-coding loci. The theoretical basis for interpreting significant covariation stems in part from Lerner's work on genetic homeostasis, which predicts that within populations increased heterozygosity will produce decreased morphological variance, owing to a buffering effect of heterosis during development. However, the prediction for the relationship between genic heterozygosity and the variance of morphological traits among populations is unclear. To determine if a relationship existed between heterozygosity and morphological variance, we compared estimates of heterozygosity and morphological variance across 15 population samples of the fox sparrow and 17 samples of the pocket gopher. The estimates of morphological variance included coefficients of variation for each character and the variance of individual scores about the population mean in a principal components analysis. Although several recent studies have reported a significant relationship between heterozygosity and morphological variance, we found that the two measures do not covary significantly.     

Lung hysteresis: a morphological view

The lung is an imperfect elastic body and for this reason dissipates energy. The energy applied to the lung in inspiration is not recovered in expiration. The property of dissipating energy receives the name of hysteresis. Lung hysteresis can be quantified because it applies to the area between the ascending and descending portions of the pressure-volume curve. Lung hysteresis comprises parenchymal hysteresis and bronchial hysteresis. Each point on the pressure-volume applies to a different morphology of the lung parenchyma. The changes that take place in the lung architecture during expiration are related to alveolar recruitment: in inspiration the lung volume increases by the opening of distal air units. In expiration the lung volume decreases due to derecruitment. The energy is dissipated mainly in the alveolar recruitment process, in which forces of molecular adhesion, such as surface tension, are at work. Bronchial hysteresis involves the dead space and the bronchial wall being greater in expiration.     

Cytological and morphological variation in Bellevalia

Material from 45 populations representing 15 species of Bellevalia were analyzed as to chromosome numbers and morphology. For 3 species reports are new, viz. for B. clusiana (2x), B, tauri (2x, 4x), and B. nivalis (4x). In B. saviczii diploids, tetraploids and hexaploids were found. The basic Bellevalia karyotype prevails, but chromosome heteromorphism is rather common at the populational level. B–chromosomes were found in some populations of B. glauca s.l. and B. saviczii. Discussions on karyotype variation, polyploidy, morphologic variation and generic delimitation are presented.