Echinoderms Through Time - read free eBook in online reader or directly download on the web page. Select files or add your book in reader. Download and read online ebook Echinoderms Through Time write by Bruno David. This book was released on 2020-12-17. Echinoderms Through Time available in PDF, EPUB and Kindle. Echinoderms are now considered as a biological and geological model that underlies researches of primary importance. The extent of the contributions made by the International Echinoderm Conferences to various fields of research is attested by the scope covered by presentation at the international conferences. These proceedings contain the complete papers or abstracts of all the presentations and posters presented at the eighth International Echinoderm Conference, held in Dijon, France in September, 1994. Coverage includes: general; extinct classes; crinoids; asteroids; ophiuroids; holothuroids; and echinoids.
Australian Echinoderms
Australian Echinoderms - read free eBook in online reader or directly download on the web page. Select files or add your book in reader. Download and read online ebook Australian Echinoderms write by Timothy O'Hara. This book was released on 2017-06. Australian Echinoderms available in PDF, EPUB and Kindle. Echinoderms, including feather stars, seastars, brittle stars, sea urchins and sea cucumbers, are some of the most beautiful and interesting animals in the sea. They play an important ecological role and several species of sea urchins and sea cucumbers form the basis of important fisheries. Over 1000 species live in Australian waters, from the shoreline to the depths of the abyssal plain and the tropics to Antarctic waters. Australian Echinoderms is an authoritative account of Australia’s 110 families of echinoderms. It brings together in a single volume comprehensive information on the identification, biology, evolution, ecology and management of these animals for the first time. Richly illustrated with beautiful photographs and written in an accessible style, Australian Echinoderms suits the needs of marine enthusiasts, academics and fisheries managers both in Australia and other geographical areas where echinoderms are studied.
Echinoderms Through Time
Echinoderms Through Time - read free eBook in online reader or directly download on the web page. Select files or add your book in reader. Download and read online ebook Echinoderms Through Time write by Bruno David. This book was released on 1994-06-01. Echinoderms Through Time available in PDF, EPUB and Kindle. Echinoderms are now considered as a biological and geological model that underlies researches of primary importance. The extent of the contributions made by the International Echinoderm Conferences to various fields of research is attested by the scope covered by presentation at the international conferences. These proceedings contain the complete papers or abstracts of all the presentations and posters presented at the eighth International Echinoderm Conference, held in Dijon, France in September, 1994. Coverage includes: general; extinct classes; crinoids; asteroids; ophiuroids; holothuroids; and echinoids.
Echinoderms Through Time
Echinoderms Through Time - read free eBook in online reader or directly download on the web page. Select files or add your book in reader. Download and read online ebook Echinoderms Through Time write by Bruno David. This book was released on 1994. Echinoderms Through Time available in PDF, EPUB and Kindle.
Reproduction and Development in Echinodermata and Prochordata
Reproduction and Development in Echinodermata and Prochordata - read free eBook in online reader or directly download on the web page. Select files or add your book in reader. Download and read online ebook Reproduction and Development in Echinodermata and Prochordata write by T. J. Pandian. This book was released on 2018-04-17. Reproduction and Development in Echinodermata and Prochordata available in PDF, EPUB and Kindle. Echinoderms and prochordates occupy a key position in vertebrate evolution. The genomes of sea urchin share 70% homology with humans. Researches on cell cycle in sea urchin and phagocytosis in asteroids have fetched Nobel Prizes. In this context, this book assumes immense importance. Echinoderms are unique, as their symmetry is bilateral in larvae but pentamerous radial in adults. The latter has eliminated the development of an anterior head and bilateral appendages. Further, the obligate need to face the substratum for locomotion and acquisition of food has eliminated their planktonic and nektonic existence. Egg size, a decisive factor in recruitment, increases with decreasing depths up to 2,000-5,000 m in lecithotrophic asteroids and ophiuroids but remains constant in their planktotrophics. Smaller ( 110 mm) asteroids generate planktotrophic eggs only. Publications on sex ratio of echinoderms indicate the genetic determination of sex at fertilization but those on hybridization, karyotype and ploidy induction do not provide evidence for heterogametism. But the herbivorous echinoids and larvacea with their gonads harboring both germ cells and Nutritive Phagocytes (NPs) have economized the transportation and hormonal costs on gonadal function. Despite the amazing potential just 2 and 3% of echinoderms undergo clonal reproduction and regeneration, respectively. Fission is triggered, when adequate reserve nutrients are accumulated. It is the most prevalent mode of clonal reproduction in holothuroids, asteroids and ophiuroids. However, budding is a more prevalent mode of clonal reproduction in colonial hemichordates and urochordates. In echinoderms, fission and budding eliminate each other. Similarly, autoregulation of early development eliminates clonal reproduction in echinoids and solitary urochordates. In pterobranchs, thaliaceans and ascidians, the repeated and rapid budding leads to colonial formation. Coloniality imposes reductions in species number and body size, generation time and life span, gonad number and fecundity as well as switching from gonochorism to simultaneous hermaphorditism and oviparity to ovoviviparity/viviparity.
