- Beginning with the dawn of the Cambrian Period (542 million to 488 million years ago), echinoderms have a rich fossil history and are well represented by many bizarre groups, most of which are now extinct.www.britannica.com/animal/echinoderm
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Origin and Early Evolution of Echinoderms | Annual Reviews
Echinoderms are a major group (phylum) of invertebrate animals with a rich fossil record stretching back to the Cambrian period, approximately 518 million years ago. While all modern species are characterized by pentaradial (i.e., fivefold) symmetry, Cambrian echinoderms …
Echinoderm - Wikipedia
Echinoderms are bilaterians, meaning that their ancestors were mirror-symmetric. Among the bilaterians, they belong to the deuterostome division, meaning that the blastopore, the first opening to form during embryo development, becomes the anus instead of the mouth. The characteristics of adult echinoderms are the possession of a water vascular system with external
Wikipedia · CC-BY-SA 许可下的文字Echinoderm | Definition, Characteristics, Species, & Facts | Britannica
- echinoderm, any of a variety of invertebrate marine animals belonging to the phylum Echinoder…
Echinoderms have been recognized since ancient times; echinoids, for example, were used extensively by Greeks and Romans for medicinal purposes and as food. During the Middle Ages, fossil echinoids and parts of fossil crinoids were objects of superstition. In the early part of the 1…
- echinoderm, any of a variety of invertebrate marine animals belonging to the phylum Echinoder…
Paleogenomics of Echinoderms | Science - AAAS
2006年11月10日 · Evolutionary history of the major echinoderm groups. Deuterostomia consists of three major groups: the chordates, hemichordates, and echinoderms, all with fossil representatives in the Cambrian. Cambrian …
Echinoderms - Smithsonian Ocean
The National Museum of Natural History contains a massive collection of echinoderms, the first of which were collected over a hundred years ago by Austin Clark aboard the US Fisheries …
Deciphering the early evolution of echinoderms with …
2015年3月5日 · Echinoderms are one of the most successful groups of marine invertebrates ever, with around 10 000 extant species belonging to five classes (asteroids, crinoids, echinoids, holothurians and ophiuroids), as well as a rich …
The active evolutionary lives of echinoderm larvae | Heredity
2006年7月19日 · Evolution of echinoderm larvae has taken place over widely varying time scales from the origins of larvae of living classes in the early Palaeozoic, approximately 500 million …
Echinoderm roots - Nature
2004年7月21日 · A bold claim about the origins of the echinoderms is based on newly discovered fossils from China. But many pieces are still missing from this part of the …
Evolution: Mapping Out Early Echinoderms - Cell Press
2020年7月6日 · Bradley Deline and colleagues probe the origins of the echinoderms with a morphometric study of their early fossil record that dates back to approximately 520 million years ago, right in the furnace of the …
Echinoderm - Evolution, Adaptations, Paleontology
2024年9月30日 · While the fossil record of echinoderms is extensive, there are many gaps, and many questions remain concerning the early evolution of the group. Ancient echinoderms exhibited an extraordinary variety of bizarre …
