When One Form is Between Two Others: An Application of Biorthogonal AnalysisBOOKSTEIN, FRED, L.
doi: 10.1093/icb/20.4.627pmid: N/A
Abstract SYNOPSIS. This essay presents a method for measuring the degree to which one biological outline form lies in between two others. The procedure does not measure forms separately, but rather compares pairs of tensors expressing D'Arcy Thompson's “Cartesian transformations” according to the biorthogonal formalism of Bookstein. In analogy with conventional methods, betweenness is computed as a similarity score, the cosine of a non- Euclidean angle between the tensors. The new quantities, size-betweenness and shapebetweenness, enable comparisons of form series against a priori orderings intra- and interspecifically This content is only available as a PDF. Author notes 1From the Symposium on Analysis of Form presented at the Annual Meeting of the American Society of Zoologists, 27–30 December 1979, at Tampa, Florida. 2This essay is dedicated to the late Kenneth B.Leisenring, Professor of Geometry at the University of Michigan. ©1980 by the American Society of Zoologists
Allometric Inference in MorphologySWEET, SAMUEL, S.
doi: 10.1093/icb/20.4.643pmid: N/A
Abstract SYNOPSIS. Disparate rates of change in the surfaces and volumes of organisms with change in size combine with the interdependence of surface-limited and volume-limited functional attributes to define criteria for the size-dependency of shapes. Size contributes to the specification of types of structures required, limits to their functional range, and the scaling relationships among components of systems. Size-dependency may be stated in terms of a null hypothesis in morphology, with departures indicative of special adaptations which may be of particular interest. The study of size-dependency in shape and function is approaching a general theory of form with content comparable in scope to a general theory of diversity. This content is only available as a PDF. Author notes 1From the Symposium on Analysis of Form presented at the Annual Meeting of the American Society of Zoologists, 27–30 December 1979, at Tampa, Florida. ©1980 by the American Society of Zoologists
Ontogenesis and Morphological DiversificationALBERCH,, PERE
doi: 10.1093/icb/20.4.653pmid: N/A
Abstract SYNOPSIS. The role of development in constraining the directionality and patterns of morphological evolution is examined. The nature of morphological variation and appearance of morphological novelties is determined by the epigenetic properties of the organism. Consideration of these properties has profound implications for current theories of morphological evolution. Developmental constraints impose severe limitations on the gradualistic action of directional selection. Evolutionis viewed as the result of differential survival of morphological novelties. However, the production of morphological novelties by developmental programs is not random. This non-randomness in morphologically expressed genetic mutations—an epigenetic property—can result in phyletic trends, parallelisms and convergences. This content is only available as a PDF. Author notes 1From the Symposium on Analysis of Form presented at the Annual Meeting of the American Society of Zoologists, 27–30 December 1979, at Tampa, Florida. 2Present address: Museum of Comparative Zoology and Department of Biology, Harvard University, Cambridge, Massachusetts 02138. ©1980 by the American Society of Zoologists
Computer Modeling of MorphogenesisJACOBSON, ANTONE, G.
doi: 10.1093/icb/20.4.669pmid: N/A
Abstract SYNOPSIS. Computer simulation is a valuable tool to help solve some problems of morphogenesis.An embryo is shaped by the behavior of its cells, but in an embryo it is often impossible to sort out which cell behaviors are active in morphogenesis because attempts to isolate one cell behavior may affect others. Computer simulation of a model of morphogenesis provides independent evidence that putative driving forces can produce a change of form. The development of a computer simulated model requires that assumptions and steps in reasoning be stated explicitly. This process brings added rigor to analysis of the biological system, improved observations of the embryo itself, and suggestions for new experiments. An interplay develops between the two systems, the actual and the simulated, in which hypotheses and experimental results from each system can be used to modify the perceptions of the other. A successful simulation can be used to simulate experiments that may not be possible on the embryo. Specific examples of how computer modeling helped analyze the shaping of the newt neural plate are discussed, as well as the prospects of extending the models to analysis of neural tube formation. This content is only available as a PDF. Author notes 1From the Symposium on Analysis of Form presented at the Annual Meeting of the American Society of Zoologists, 27–30 December 1979, at Tampa, Florida. ©1980 by the American Society of Zoologists
Multivariate Analysis and the Study of Form, with Special Reference to Canonical Variate AnalysisALBRECHT, GENE, H.
doi: 10.1093/icb/20.4.679pmid: N/A
Abstract SYNOPSIS. This paper presents a simple, geometric, largely intuitive introduction to the use of multivariate analysis for the study of biological form. Rather than presenting rigorous mathematical formulations of the theory and practice of statistics, the emphasis is on multivariate analysis as a descriptive, data-analytic approach which represents the quantitative version of classical comparative anatomy. One method—canonical variate analysis—is chosen for special attention because of its wide applicability to problems in which multidimensional data are used to compare differences between two, several, or many populations with proper regard for individual variation within the populations. The theory, practice, and utility of canonical variate analysis are presented by way of simple, bivariate examples. Particular attention is given to how the results of canonical variate analysis are affected by alterations in the within-group dispersion when the relationships among groups are held constant. Although the discussion focuses on canonical variate analysis, many statements transfer directly or with appropriate modification to the use of other multivariate procedures in comparative morphology. This content is only available as a PDF. Author notes 1From the Symposium on Analysis of Form presented at the Annual Meeting of the American Society of Zoologists, 27–30 December 1979, at Tampa, Florida. ©1980 by the American Society of Zoologists
The Analysis of Form: Without Measurement and Without ComputersOXNARD, CHARLES, ERNEST
doi: 10.1093/icb/20.4.695pmid: N/A
Abstract SYNOPSIS. An attempt is made to argue from discrete measurement of shape, through field representations of form, to analyses that encompass entire patterns. One method for achieving this last is the optical Fourier transformation. Examples of how it works on theoretical patterns are presented. Results of practical studies of actual radiographs of cancellous patterns in vertebral bodies of humans and apes are given. Architectural elements totally unsuspected from normal radiographic examinations are found. And it is shown that these have implications for our understanding of the nature of the relationship between bone architecture and stress bearing. The application more widely of such a method for the analysis of complex patterns is noted. This content is only available as a PDF. Author notes 1From the Symposium on Analysis of Form presented at the Annual Meeting of the American Society of Zoologists, 27–30 December 1979, at Tampa, Florida. ©1980 by the American Society of Zoologists
Biomechanical Models and the Analysis of Form: A Study of the Mammalian Masticatory ApparatusWEIJS, WILHELMUS, A.
doi: 10.1093/icb/20.4.707pmid: N/A
Abstract SYNOPSIS. Biomechanical models of the mammalian masticatory system were traditionally based on a simple classification of feeding types and prediction of function from form. The functional significance of spatial relationships between teeth, muscles and jaw joint, the shape of the mandible and sizes of the jaw muscles were explained in terms of optimal transmission of muscle forces to a specific bite point. Direct, experimental study of jaw movements and muscle activities has revealed new data, highly relevant to the construction of realistic mechanical models and the explanation of aspects of the morphology of the chewing apparatus. The jaw muscles do not reach comparable percentages of their maximum force simultaneously. The relative involvement of each muscle depends on the bite point. During mastication they fire in complicated patterns of successive, partially overlapping contractions. The linear relationship between electromyogram and muscular tension may be employed to estimate muscular tension in vivo. Computed resultant forces gradually change in magnitude and direction during chewing cycles; there is a close correlation with the jaw movements. The necessity to perform the movements may be an extra constraint on jaw muscle morphology. If muscle force estimates are used in a threedimensional static analysis, bite forces and joint reaction forces are found, different from those resulting from one- (simple lever) or two-dimensional static analysis. The explanation of tooth and joint morphology is influenced by these modifications. This content is only available as a PDF. Author notes 1From the Symposium on Analysis of Form presented at the Annual Meeting of the American Society of Zoologists, 27–30 December 1979, at Tampa, Florida. ©1980 by the American Society of Zoologists
Abstractdoi: 10.1093/icb/20.4.723pmid: N/A
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