Johannesson k (17 Ergebnisse)

12pp, 3 figs, Printed Card Cover, VGC.

14pp, 2 figs, Printed Card Cover, VGC.

Zustand: Good. This is an ex-library book and may have the usual library/used-book markings inside.This book has hardback covers. In good all round condition. No dust jacket. Please note the Image in this listing is a stock photo and may not match the covers of the actual item,700grams, ISBN:0520070135. …

paperback. Zustand: New. 1st.

Kartoniert-O. Zustand: Gut. 1. Auflage.. 64 Seiten, 8°, mit reichh.Fotomat., in engl. Sprache, gutes Exemplar. P21596_Werften Sprache: Englisch Gewicht in Gramm: 400.

Galician exposed shore populations of the direct developing periwinkle Littorina saxatilis are strikingly polymorphic, with an ornamented and banded upper shore form and a smooth and unbanded lower shore form. Intermediates between the two pure forms occur in a narrow mid shore zone together with the parental forms. We have previously shown that the two pure forms share the same gene pool but that mating between them is non-random. This is due to a non-random microdistribution in the zone of overlap, and also to assortative mating. In this study we present data which show that intermediate (hybrid) females mate less often than pure females in micropatches dominated by either of the pure forms, but not in micropatches in which the two pure forms are equally common. Thus, sexual fitness in intermediate females depends on the frequency of both pure morphs. Furthermore, sexual selection against intermediate females also varies with the densities of snails within each micro patch. The biological mechanisms which may explain this particular reduction of female hybrid fitness are discussed. Assortative mating between the pure morphs is sometimes almost complete, while both morphs do not mate the intermediates assortatively. In the light of this, sexual selection against intermediate females may contribute considerably to restrict gene flow between the pure forms. 6 pp., 2 tabs, 4.…

The ovoviviparous Littorina saxatilis (Olivi) can be found in many intertidal habitats. Winkles from different habitats have different morphologies and behaviours, which are usually argued to reflect adaptations. Whether the different forms are caused by genetic differentiation or due to phenotypic plasticity is, however, less discussed. Our aim was to document morphological and behavioural differences among one exposed rock poulation, one sheltered boulder population, and one mud flat population, and we reared offspring in a common laboratory environment to see if the differences persisted. We used principal component analysis (PCA), based on 19 measurements, to compare size and shape differences. We also used PCA and linear regression to study allometry and compare growth trajectories. Behavioural differences were studied in three laboratory trials. Littorina saxatillis from the rock were relatively small, had small aperture lips, thin shells, blunt spires, and wide columellae. They preferred to stay in cracks and to be above the water surface, and they quickly emerged out of their shells after disturbance. L. saxatillis from the boulder shore were relatively large, had large lips, thick shells, pointed spires, and narrow columellae. They preferred open surfaces, submergence, and after disturbance they slowly emerged out of the shell. L. saxatilis from the mud flat were relatively small, had small lips, think shells, pointed spires, and narrow columellae and most behaved similarly to the boulder shore snails. Although less pronounced, most of these morphological and behavioural differences persisted in the snails that we reared in the common environment. This indicates some genetic differentiation. All groups grew allometrically, and most groups differed in growth trajectories, Despite similar ages, the reared females were generally larger than the reared males, indicating higher growth rate in females. Sexual maturation seemed to be reached at a certain size rather than at a certain age. Theories predict genetic diferentiation in intertidal snail species with low dispersal, but some investigations show results that contradict the theories, while others agree with them. Our study confirms the prediction that L. saxatilis should be genetically differentiated. 19 pp., 5 figs, gr. 8.…

geheftet. Zustand: Sehr gut. S.64; mit reichh.Fotomat., 22 cm Zustand: sehr gut - neuwertig F-R8055 Wenn das Buch einen Schutzumschlag hat, ist das ausdrücklich erwähnt. Rechnung mit ausgewiesener Mwst. Sprache: Englisch Gewicht in Gramm: 175.

Paperback. Zustand: Brand New. 288 pages. 10.24x7.60x0.68 inches. In Stock.

Taschenbuch. Zustand: Neu. Druck auf Anfrage Neuware - Printed after ordering - Littoral gastropods of the families Littorinidae and Muricidae are well studied compared to most marine taxa, yet there remain many basic problems concerning their taxonomy, ecology and evolutionary biology. In other words, we know these snails well enough to realize just how little we really know about them. This awareness prompted the First European Meeting on Littorinid Biology held at the British Museum in London on 26th November 1986, and the discussion continued through the Second Meeting on Littorinid Biology, held at the Tjarno Marine Biological Laboratory, Sweden, from 4th to 8th July 1988. During the Tjiirno meeting, it was agreed to have a third meeting at Dale, Pembroke shire, U.K. in 1990. Twenty-two people attended the Tjarno meeting, and a further ten contributed as co-authors to the papers that were presented. These covered research in progress in a broad range of topics, and geo graphical areas. Unfortunately, Cesare Sacchi and Domenico Voltolina, as well as Elisabeth Boulding were not able to attend the meeting in person, but their contributions were ably presented by David Reid and Richard Palmer, respectively. We also regret that one of us, C.E., and several of our Russian colleagues, did not have the opportunity to come.…

Zustand: New.

Zustand: New. 2007. Paperback. . . . . . Books ship from the US and Ireland.

Paperback. Zustand: Good +. First Edition. viii, 249 pp. Maps. Tables. FAO Fisheries Technical Paper 240. Label removed from spine, leaving mark. Light wear otherwise. Includes references and recommended reading. Echo sounding in fishing.

Zustand: Sehr gut. Zustand: Sehr gut | Seiten: 304 | Sprache: Englisch | Produktart: Bücher | This volume contains papers of leading experts in the modern continuum theory of composite materials. The papers expose in detail the newest ideas, approaches, results and perspectives in this broadly interdisciplinary field ranging from pure and applied mathematics, mechanics, physics and materials science. The emphasis is on mathematical modelling and model analysis of the mechanical behaviour and strength of composites, including methods of predicting effective macroscopic properties (dielectric, elastic, nonlinear, inelastic, plastic and thermoplastic) from known microstructures.…

Zustand: New.

Stockholm 1978. L-8vo. 348 pp. (Lychnos-Bibl.31).

geheftet. Zustand: Sehr gut. 1. Aufl. 64 Seiten; mit reichh.Fotomat., Zustand: sehr gut - neuwertig F-R8056 Wenn das Buch einen Schutzumschlag hat, ist das ausdrücklich erwähnt. Rechnung mit ausgewiesener Mwst. Sprache: Deutsch Gewicht in Gramm: 160.