General Characters, Example of Urochordata and Cephalochordata , Multiple Choice questions: NEET
🌑General Characters
🔴They are mostly marine, colonial or solitary but some are pelagic also.
🔴Body is covered by test that is made up of Tunicin similar to cellulose or polysaccharide hence called as Tunicata.
🔴Animals are bilateral symmetrical, Triploblastic with organ system evel of organisation.
🔴Notochord is present in tail region of larval but not in adult because tail is absent in adult.
🔴Adult are sessile but larvae are free swimming.
🔴Alimentary canal is complete with large pharynx and endostyle.
🔴Respiration takes place through gill or test but two to many gills slits are also present.
🔴A dorsal atrial aperture and a terminal branchial aperture is present .
🔴Neural gland, pyloric gland and nephrocyte are present as excretory organ.
🔴A ventral tubular heart is present with open blood vascular system.
🔴Vanadocytes are present to extract the vanadium from the sea water.
🔴Reproduction is mostly sexual but some reproduce by budding also.
🔴Development is indirect with Retrogressive metamorphosis. And fertilisation is external.
🌑Example of Urochordates
🔴It is commonly known as sea Squirts.
🔴Body of Ascidia is barrel shaped and attached with the substrate with branchial siphon.
🔴It has two prominent siphon to take water and food though filter feeding.
🔴It has a tough test made up of polysaccharide called as Tunicin.
🔴Larval of Ascidia is called as Tadpole which has dorsal nerve cord, pharyngeal gill slit and post anal tail.
🔴During metamorphosis, Larva lost tail and assume sac like body.
🔴Ascidia has sac like body and filter feeder in nature.
🔴It is hermaphrodite. Male and female gonad are found on same animal.
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🌑Defination
🔴Cephalochordates are put under sub phylum of Chordata fish like,filter feeder and marine animals included Amphioxus or lancelet.
🌑General Characters
🔴They are mostly marine, fish like, segmented with elongated body.
🔴Alimentary canal is long with pharynx and gills slits with ciliary mode of feeding.
🔴Dorsal, caudal and ventral fins are present.
🔴Notochord is present from head to tail and remain present through out the life.
🔴Protonephridia and Solenoacytes are excretory organ.
🔴Two pair of cerebral nerve and several pairs of spinal nerve are present.
🔴Respiration takes place through gills slits are also present. Coelom is enterocoelic.
🔴Saxes are separate. Gonads are present without gonoduct.Fertilisation is external.
🔴Body is eel like and well adapted for burrowing .
🔴They have an endostyle in their pharynx for filter feeding.
🔴Reproduction is mostly sexual. Asexual reproduction is absent.
🔴Circulatory system is closed.Brain is absent.
🌑Example of Cephalochordata
🟡Amphioxus
🔴It is also called as Branchiostoma or Lamprey.
🔴It has dorsal nerve cord, Notochord , gills slits and post anal tail.
🔴It has a wide mouth at trunk ,anus on caudal fin and atriopore.
🔴Mostly they are burrowing but they can swim by the myotomes.
1. Which of following statement is not correct.
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