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学科类别:动物或水产 适宜对象:小学高年级至初二学生 构思原理:蟹类动物属节肢动物门甲壳纲十足目短尾亚目动物。这类动物的头胸甲特别发达,有圆型、椭圆型、方型和梭型不等,腹部退化折叠于胸部的腹面,称腹脐,腹节愈合,尾节很小。蟹类的附肢已特化成形态各不相同,并具有不同功能的附肢,附肢包括前端的二对触角,组成口器的一对大腭、二对小腭,五对胸足,其中第1对为钳状螯足,2～4对为步行足,第5对因生活习性不同,善爬行的为步行足,经游泳的为游泳足,腹足已退化,排列在腹脐里面。
Subject category: Animal or Aquaculture Suitable target: Primary to Secondary 2 Primary School Students Conceptual principles: Crabs Arthropods Crustacean Decapoda species. The head cuirass of these animals are particularly well developed, ranging from round, elliptical, square and shuttle types. The abdomen degenerates and folds on the ventral side of the chest. The abdominal umbilicus is called, and the abdomen is healed with a very small tail section. The appendages of crabs have been specially shaped into different appendages and have appendages with different functions. The appendages include two pairs of tentacles at the front end, a pair of big urns forming mouthparts, two pairs of small lice, and five pairs of thoracic feet. The first pair was a pincer claw-like peduncle. Two to four pairs were walking feet. The fifth pair was walking feet because of different living habits. The swimming feet were the swimming feet and the gastropods had been degraded and arranged in the abdominal umbilicus.