Give the characteristic features of the following citing one example of each
a. Chondrichthyes and ostichthyes
b. Urochordata and cephalochordata
a. Chondricthyes: They have cartilaginous endoskeleton. Their gills are not covered by operculum. They are mainly marine and their body is streamlined. They are predaceous. Due to the absence of air bladder, they have to swim constantly to avoid sinking. Example: Trygon, Scoliodon, Pristis etc.
Osteicthyes: They have bony endoskeleton. They are both marine and fresh water fishes. Their body is streamlined. Gills are covered with operculum, skin is covered with cycloid/ ctenoid scales. Air bladder is present which regulates buoyancy. Example: Labeo rohita, Catla catla.
b. Urochordata and Cephalochordata: In Urochordata, the notochord is present only in larval tail and disappears in adults. Example: Salpa, Herdmania etc. In Cephalochordates, notochord extends from head or tip of the snout to tail region and persists throughout the life. Example: Brachiostoma.
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a. Chondricthyes: They have cartilaginous endoskeleton. Their gills are not covered by operculum. They are mainly marine and their body is streamlined. They are predaceous. Due to the absence of air bladder, they have to...
Step-by-step explanation:
• a
• Chondricthyes: They have cartilaginous endoskeleton
• Their gills are not covered by operculum
• They are mainly marine and their body is streamlined
• They are predaceous
Students often lose marks by skipping steps, writing incomplete explanations, or misunderstanding keywords used in the question.
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