精选初二上册生物知识点：动物的主要类群（第五单元）

1、.精选初二上册生物知识点：动物的主要类群第五单元学习是一个循序渐进的过程，也是一个不断积累不断创新的过程。下面小编为大家整理了精选初二上册生物知识点：动物的主要类群第五单元，欢送大家参考阅读!一、蚯蚓属于环节动物。1.身体分节，可以增强运动的灵敏性，通过肌肉和刚毛来完成运动。2.体壁分泌黏液，保持潮湿以保证呼吸。3.环节动物的特征：身体由许多相似的体节构成。4.常见种类：蚯蚓、水 蛭等。二、蝗虫是节肢动物的代表。1.蝗虫构造：身体 分为头部、胸部、腹部三部分，体表坚硬具有外骨骼运动构造：三对足，两对翅，后足兴隆适于跳跃，前翅革质起保护作用，后翅膜质合适飞翔。感觉构造：一对复眼，三个单眼，触角分

2、节。呼吸构造：进出气体的构造为气门。2.节肢动物的特征：身体分部，躯体、足和触角分节，体表具有外骨骼。3.节肢动物适于陆地生活的原因：体表有外骨骼 , 运动器官兴隆等。三、鱼类鲫鱼1.身体呈梭形，合适游泳。2.体表具有鳞片;背部体色深灰黑色，腹部白色，是一种保护色。3.用鳃呼吸，用鳍游泳。4.侧线作用：感知水流测定方向。四、鸟类1.体形：流线型。2.飞行器官：前肢特化为翼。3.肌肉：胸肌兴隆。4.骨骼：具有龙骨突，有的骨中空，有的骨愈合。5.消化：消化系统兴隆，直肠极短。6.呼吸方式：双重呼吸，用肺呼吸，气囊辅助呼吸。7.体温：恒定。五、哺乳动物1 .体表：被毛，保温有作用。2.体腔：有膈，将

3、体腔分为胸腔和腹腔。3.牙齿：分为门齿和臼齿，适于切断、磨碎食物。4.呼吸：用肺呼吸。5.体温：恒定。6.神经系统：由脑、脊髓和神经组成，大脑兴隆。以上就是查字典生物网为大家整理的精选初二上册生物知识点：动物的主要类群第五单元，怎么样，大家还满意吗?希望对大家的学习有所帮助，同时也祝大家学习进步，考试顺利!ectable="on" role="presentation" style="padding: 1px 3px; margin: 0px; font-family: Arial, sans-serif; border-width: 0px

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