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DESCRIPTIONPhylum Echinodermata. Upper ( ARKARUA ) Lower ( left: middle cambrian ctenocyctis carpoid fossil, right: Jurassic sea urchin ). What are Echinoderms?. are a phylum of marine animals they belong to Kingdom Animalia, under Subkingdom Eumetozoa, and Superphylum Deuterostomia - PowerPoint PPT Presentation
Upper ( ARKARUA )Lower ( left: middle cambrian ctenocyctis carpoid fossil, right: Jurassic sea urchin )
What are Echinoderms?are aphylumofmarineanimals they belong to Kingdom Animalia, under Subkingdom Eumetozoa, and Superphylum Deuterostomiathey are found from intertidal zone to abyssal zone of the oceanslargest phylum with no freshwater or terrestrial representatives
TaxonomymotileEleutherozoa *Asteroidea (starfish) *Ophiuroidea (brittle stars) *Echinoidea (sea urchinsandsand dollars) *Holothuroidea (sea cucumbers) sessilePelmatazoa *crinoids*extinct paracrinoids
-> two main subdivisions of echinoderms
the echinoderms(motile eleutherozoa)
the echinoderms(sessile pelmatozoa)
Anatomy and Physiology plus Skin and Skeletonevolved from animals withbilateral symmetry the left side of the body grows at the expense of the right side, which is eventually absorbed. The left side then grows in apentaradiallysymmetric fashion, in which the body is arranged in five parts around a central axis. have amesodermalskeleton composed of calcareous plates or ossicles their epidermis consists of cells responsible for the support and maintenance of the skeleton, as well as pigment cells,mechanoreceptorcells, which detect motion on the animal's surface, and sometimes gland cells which secrete sticky fluids or eventoxins. the colours are produced by a variable combination of coloured pigments, such as the darkmelanin, redcarotinoids, andcarotinproteins, which can be blue, green, or violet.
The Water Vascular Systema network of fluid-filled canals that function in gas exchange, feeding, and secondarily in locomotion. This system is derived from both the hydrocoel and axocoel. This system may have allowed echinoderms to function without the gill slits found in other deuterostomes.
Evolution first universally accepted echinoderms appear in the Lower Cambrian period (Paul and Smith 1984). Based on their bilateral larvae, many zoologists argue that echinoderm ancestors were bilateral and that their coelom had three pairs of spaces (trimeric).Some have proposed that radial symmetry arose in a free-moving echinoderm ancestor and that sessile groups were derived several times independently from free-moving ancestors. first echinoderms were sessile, became radial as an adaptation to that existence, and then gave rise to free-moving groups.
Ecological roles of echinoderms grazing of sea urchins reduces the rate of colonization of bare rockthe burrowing of sand dollars and sea cucumbers depleted the sea floor of nutrients and encouraged deeper penetration of the sea floor, increasing the depth to which oxygenation occurs and allowing a more complex ecological tiering to develop.Starfish and brittle stars prevent the growth of algal mats on coral reefs, which would obstruct the filter-feeding constituent organisms.Some sea urchins can bore into solid rock; this bioerosion can destabilise rock faces and release nutrients into the ocean.many sea cucumbers provide a habitat for parasites, including crabs, worms and snails
Benefits to Human..elements of many cuisinesThe calcareous tests or shells of echinoderms are used as a source of lime by farmers in areas where limestone is unavailablepopular collectibles
Thank YouMaraming Salamat.