Q. Fish identity card. How are fishes characterized according to examples of representing beings, skin, basic morphology, circulation, nitrogen waste, respiration, thermal control and types of reproduction?
Examples of representing beings: tuna, sardines, sharks, rays, salmons. Basic morphology: hydrodynamic body, fins cartilaginous skeleton in chondrichthyes, bony skeleton in osteichthyes. Skin: with scales in placoid and osteichthyes scales in chondrichthyes. Respiration: branchial, Circulation: incomplete, closed, heart with two chambers. Nitrogen waste: urea in chondrichthyes, ammonia in osteichthyes. Thermal control: heterothermic. Kind of reproduction: sexual, internal fecundation in chondrichthyes, external in osteichthyes.