Practical Studies of Animal Development
Practical Studies of Animal Development

Author: F. S. Billett

Publisher: Springer Science & Business Media

Published: 2012-12-06

Total Pages: 267

ISBN-13: 9401168849

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The purpose of this book is twofold: it is meant to serve both as a practical manual for the study of animal development and as a general introduction to the subject. Central to our en deavour is the belief that developmental biology is best taught and learnt at the laboratory bench, with specimens which are either alive and can be seen to develop or with fresh material derived directly from the egg (as in birds) or mother (as in mammals). Once the dynamic nature of development is appreci ated and the overall structure of the developing organism discerned the more conventional study of sections and whole mounts is more likely to become a delight rather than a diffi cult, and often meaningless, chore. We have laid considerable stress on the early development of animal embryos and the ways in which they can be obtained from a relatively few, but reliable, sources. In addition, emphasis has been placed on fairly simple experiments which make use of the embryos and larvae chosen for the purpose of illustrating develop ment. Embryology ceased to be a descriptive science at the beginning of this century and any practical course, at what ever level, should attempt to reflect this change. It is true that the analysis of development, particularly the genesis of chor date structure, owed much to the invention of the microtome.

Annelida Basal Groups and Pleistoannelida, Sedentaria I
Annelida Basal Groups and Pleistoannelida, Sedentaria I

Author: Günter Purschke

Publisher: Walter de Gruyter GmbH & Co KG

Published: 2019-03-18

Total Pages: 492

ISBN-13: 3110291584

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This book is the first in a series of 4 volumes in the Handbook of Zoology series about morphology, anatomy, reproduction, development, ecology, phylogeny and systematics of Annelida. This first volume covers members of the so-called basal radiation and the first part of Sedentaria. It is supplemented by chapters on the history of annelid research, their fossil record, and an introduction to the phylogeny of annelids and their position in the tree of life. In the latter chapter the history of their systematic is reviewed giving an almost complete picture of systematic-scientific progress especially in the past years which changed our view on annelid phylogeny dramatically. The most basal annelids, lately united as Palaeoannelida, represent two families of aberrant polychaetes formerly often suggested to be highly derived which now give us a fresh look on how the ancestral annelid may have looked like. These lack certain key characters such as nuchal organs and possess rather simple nervous systems which now likely represent primitive character states. In this basal radiation the first taxon of apparently unsegmented and achaetigerous animals is positioned, the Sipuncula. Most likely another group of platyhelminth-like and unsegmented and even chaeta-lees annelids, Lobatocerebridae falls into this basal radiation. The section of Sedentaria starts with Orbiniida, a taxon characterized by elongated, thread-like worms which do not have anterior appendages like palps and comprises several families representing members of the Meiofauna. These minute worms often inhabiting the interstitial spaces in marine sands are suggested to have evolved by progenesis. The second higher taxon is represented by Cirratuliformia comprising nine families of typical sedentary polychaetes each of which showing a remarkable variation of the annelid body plan. Members of this taxon usually exhibit many annelid characters but certain also lack the most typical prostomial appendages, the palps.

Acoelomate and Pseudocoelomate Metazoans
Acoelomate and Pseudocoelomate Metazoans

Author: Arthur C. Giese

Publisher: Elsevier

Published: 2013-09-17

Total Pages: 559

ISBN-13: 1483260550

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Reproduction of Marine Invertebrates, Volume I: Acoelomate and Pseudocoelomate Metazoans is a collection of papers that deals with the evolution of reproductive mechanisms and behavior in marine invertebrates. This collection starts with terminologies and basic events in marine invertebrate reproduction, including the method of estimating sexual reproductive activity, as well as the timing and patterns involved. The book notes that temperatures, salinities, or food availability should be favorable when the young are produced and when they are developing. One paper shows that the reproductive rhythm is dynamic and in some species is latitude-dependent. Other papers discuss the reproductive cycles of different marine invertebrates such as the Porifera, Cnidaria, Nemertinea, and Nematoda. These papers include topics on asexual reproduction, regeneration, sexual reproduction, and development, and then explain in detail the development of certain invertebrates from their kinorhynchs state (embryonic), to the molting stages, juvenile stages, then to adulthood. This book can be useful for marine biologists, marine ecologists, and students involved in marine biological and physical sciences.

The Sea Urchin Embryo
The Sea Urchin Embryo

Author: G. Czihak

Publisher: Springer Science & Business Media

Published: 2012-12-06

Total Pages: 719

ISBN-13: 3642659640

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Sea urchin eggs are objects of wonder for the student who sees them for the first time under the microscope. The formation of the fertil ization membrane after insemination, the beauty of mitotic cleavage, the elegant swimming of embryos, remain an esthetic pleasure even for the eyes of seasoned investigators. But sea urchin eggs have other, more practical, advantages: they lend themselves to surgical operation without difficulty and they heal perfectly; they can be obtained in very large amounts and represent thus an extremely favorable material for biochemists and molecular embryologists. It is not surprising that, in view of these exceptional advantages, sea urchin eggs have attracted the interest of innumerable biologists since O. HERTWIG discovered the fusion of the pronuclei (amphimixy), in Paracentrotus lividus, almost a century ago. The purpose of the present book is to present, in a complete and orderly fashion, the enormous amount of information which has been gathered, in the course of a hun dred years of sea urchin embryology. JOSEPH NEEDHAM, in 1930, was still able to present all that was known, at that time, on the biochemistry of all possible species of developing eggs and embryos in his famous "Chemical Embryology" (Cambridge University Press) . It would no longer be possible for one man to write a modern version of what was a "Bible" for the young embryologists of forty years ago.