biology
Echinoderm
Echinoderm diversity
Scientific classification
Kingdom:
Animalia
Subkingdom:
Eumetazoa
Superphylum:
Deuterostomia
Phylum:
Echinodermata
Klein, 1734
Subphyla & Classes
Homalozoa † Gill & Caster, 1960
Homostelea †
Homoiostelea †
Stylophora †
Ctenocystoidea † Robison & Sprinkle, 1969
Crinozoa
Crinoidea
Paracrinoidea † Regnéll, 1945
Cystoidea † von Buch, 1846
Asterozoa
Ophiuroidea
Asteroidea
Echinozoa
Echinoidea
Holothuroidea
Ophiocistioidea †
Helicoplacoidea †
?Arkarua †
Pelmatozoa
Edrioasteroidea †
Blastozoa †
Blastoidea †
Eocrinoidea †Jaekel, 1899
† = Extinct
Echinoderms (Phylum Echinodermata from Greek, ἐχῖνος, echinos – "hedgehog" und δέρμα, derma – "skin") are a phylum of marineanimals. The adults are recognizable by their (usually five-point) radial symmetry, and include such well-known animals as starfish, sea urchins, sand dollars, and sea cucumbers. Echinoderms are found at every ocean depth, from the intertidal zone to the abyssal zone. The phylum contains about 7000 living species,[1] making it the second-largest grouping of deuterostomes (a superphylum), after thechordates (which include the vertebrates, such as birds, fish, mammals, and reptiles). Echinoderms are also the largest phylum that has no freshwater or terrestrial (land-based) representatives.
Aside from the hard-to-classify Arkarua (a Precambrian animal with Echinoderm-like pentamerous radial symmetry), the first definitive members of the phylum appeared near the start of the Cambrian period. The word "echinoderm" is made up from Greek ἐχινόδερμα (echinóderma), "spiny skin", cf. ἐχῖνος (echínos), "hedgehog; sea-urchin" and δέρμα (dérma), "skin", echinodérmata being the Greek plural form.[2]
The echinoderms are important both biologically and geologically. Biologically, there are few other groupings so abundant in the biotic desert of the deep sea, as well as shallower oceans. The more notably distinct trait, which most echinoderms have, is
Echinoderm diversity
Scientific classification
Kingdom:
Animalia
Subkingdom:
Eumetazoa
Superphylum:
Deuterostomia
Phylum:
Echinodermata
Klein, 1734
Subphyla & Classes
Homalozoa † Gill & Caster, 1960
Homostelea †
Homoiostelea †
Stylophora †
Ctenocystoidea † Robison & Sprinkle, 1969
Crinozoa
Crinoidea
Paracrinoidea † Regnéll, 1945
Cystoidea † von Buch, 1846
Asterozoa
Ophiuroidea
Asteroidea
Echinozoa
Echinoidea
Holothuroidea
Ophiocistioidea †
Helicoplacoidea †
?Arkarua †
Pelmatozoa
Edrioasteroidea †
Blastozoa †
Blastoidea †
Eocrinoidea †Jaekel, 1899
† = Extinct
Echinoderms (Phylum Echinodermata from Greek, ἐχῖνος, echinos – "hedgehog" und δέρμα, derma – "skin") are a phylum of marineanimals. The adults are recognizable by their (usually five-point) radial symmetry, and include such well-known animals as starfish, sea urchins, sand dollars, and sea cucumbers. Echinoderms are found at every ocean depth, from the intertidal zone to the abyssal zone. The phylum contains about 7000 living species,[1] making it the second-largest grouping of deuterostomes (a superphylum), after thechordates (which include the vertebrates, such as birds, fish, mammals, and reptiles). Echinoderms are also the largest phylum that has no freshwater or terrestrial (land-based) representatives.
Aside from the hard-to-classify Arkarua (a Precambrian animal with Echinoderm-like pentamerous radial symmetry), the first definitive members of the phylum appeared near the start of the Cambrian period. The word "echinoderm" is made up from Greek ἐχινόδερμα (echinóderma), "spiny skin", cf. ἐχῖνος (echínos), "hedgehog; sea-urchin" and δέρμα (dérma), "skin", echinodérmata being the Greek plural form.[2]
The echinoderms are important both biologically and geologically. Biologically, there are few other groupings so abundant in the biotic desert of the deep sea, as well as shallower oceans. The more notably distinct trait, which most echinoderms have, is