摘要:

AbstractDiscontinuous activity of genes and evolution ‐ a discussion based on examples of the Archaeognatha (Insecta)On the basis of examples, mainly from the group of Archaeognatha (Insecta) it seems probable that, in multicellular organisms, there is not only a discontinuous activity of genes and groups of genes during the individual development, but also during the phylogenesis. The possibility that silent genes can be reactivated is probably an essential reason for the existence of parallelisms and homologous tendencies. Both conceptions have a complementary importance for an establishment of taxa ana the reconstruction of phylogenesis and are defined according to evolutionary genetics. The examples are discussed and the necessity of similar comparative studies in other supraspecific taxa is emphasize

ISSN:0947-5745    

DOI:10.1111/j.1439-0469.1994.tb00486.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractFrom epiphytic mosses and ferns of remnants of mountain forest in the páramo region of Colombia,Sturmius epiphytusn. gen. n. spec, a taxon that resembles the Katianniformia, is described, the appendices anales of which are, however, directed towards the posterior. Analysis of characters allows a statement of the systematic position: in phylogenetic systematics,Sturmius epiphytusand the Katianniformia form a monophylum Anteriora as the sister group of the Sminthuriformia; in Linnean categories, forSturmiusn. gen., a new family Sturmiidae must be established with a new superfamily Sturmioidea as the sister group of a new superfamily Katiannoidea

ISSN:0947-5745    

DOI:10.1111/j.1439-0469.1994.tb00487.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractGenetic differentiation in the four nominal speciesC. nitens(Gallenstein, 1848),C. lubricella(Porro, 1838),C. lubrica(O. F. Müller, 1774) andC. repentinaHudec, 1960 was studied by investigating 21 isoenzyme loci. Allozymic markers exist, which clearly separate the first three taxa from each other, including in sympatric areas. By contrast,C. repentinaandC. lubricaexhibit almost no isozymic differentiation and therefore,C. repentinashould not be considered as a separate species, but as a member ofC. lubricasensu lato. The high frequency of homozygotes within all populations of all species shows that self‐fertilization is the main breeding system of Cochlicopa. Genetic relationships between the various populations were inferred with different tree‐constructing methods. In all phenograms, populations ofC. nitensappear in one distinct cluster, whereas the grouping ofC. lubricellachanges when different clustering‐procedures are used. Therefore, it remains unclear whether the three populations ofC. lubricellahave a common origin or whether they are polyphyletic with at least two independent anc

ISSN:0947-5745    

DOI:10.1111/j.1439-0469.1994.tb00488.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractThe various systems proposed to describe concisely, in the form of a formula, the number and arrangement of keratodont rows in the oral disk of anuran tadpoles, are reviewed and classified. A distinction is made between individual and collective keratodont formulae. The different systems are compared and evaluated, and proposals are made to standardize the use of various signs, numerals and letters in keratodont formulae. Nine standardized systems (seven all‐cardinal and two cardinal‐ordinal systems) are finally retained: these should cover all needs according to the kind of use and the level of precision requi

ISSN:0947-5745    

DOI:10.1111/j.1439-0469.1994.tb00489.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractThis scanning‐electron microscopic study demonstrates the convergent evolution of the mouthparts of various herbivorous stream animals (insects from different orders, an isopod, snails, fish, and a tadpole) feeding on epilithic algal pastures. This food source is rich but is often difficult to harvest. Nevertheless, a large number of species can live on it because they have evolved highly specialized mouthparts. There are four functional problems that an algae grazer has to solve: the algae must be removed from the stone, they have to be collected and crushed, and a current shield is needed to prevent the water flow sweeping away the food.Among the 30 algae grazers examined in this study, a limited number of morphological solutions have been found for each of these adaptational problems. There are multiple evolutionary pathways for mouthpart adaptation and even closely related species have often evolved different types of tools for the same function. This refects the existence of a certain amount of evolutionary scope. Such freedom of evolution is present, however, only at the beginning of the adaptiogenesis of an algae grazer. Once one of the evolutionary pathways is taken, further improvement of the mouthparts is possible only by the refinement of the ‘chosen’ type of tools. The consequence of this is that a large number of astonishing convergences have occurred in algae grazers that have independently trodden the same evolutionary pa

ISSN:0947-5745    

DOI:10.1111/j.1439-0469.1994.tb00490.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Books reviews in this article:Jarofke,D.; Lange,J.: Reptilien. Krankheiten und Haltung.Kalb,J. E.; Mebrate,A.: Fossil elephantoids from the hominid‐bearing Awash group, middle Awash Valley, Afar Depression, Ethiopia.Rentz,D. C. F.: Tettigonüdae of Australia. Vol. 2: The Austrosaginae, Zaprochilinae and Phasmodinae.Bittner,A. (ed.): Madagaskar ‐ Menschen und Natur itn Konflikt.Old,R. W.; Primrose,S. B.: Gentechnologie ‐ Eine Einführung.Ueckermann,E.: Das Sikawild. Vorkommen, Naturgeschichte, Bejagung. 2., neubearb. u. enw. Aufl.Riedl,R.: Wahrheit und Wahrscheinlichkeit. Biologische Grundlagen des Für‐Wahr‐Nehmens.Remo,M. A.; Thompson,R. L.: Forbidden Archeology: The Hidden History of th

ISSN:0947-5745    

DOI:10.1111/j.1439-0469.1994.tb00491.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY