最高等的动物门类--脊索动物门（Chordata）.ppt

CHORDATES (脊索动物门)
Intruduction
Definition(脊索动物的定义)
The great phylum chordata(脊索动物门) derives its name from one of the mon characteristics of this group --the notochord. This structure is possessed by all members of the phylum, either in the larval or embryonic stages or throughout life.
The three distinctive characteristics that chordates apart from all other phyla are the notochord, dorsal tubular nerve cord, and pharyngeal gill slits. These characteristics are always found in the early embryo, although they may be altered or may disappear altogether in later stages of the life cycle. These four features are so important that each merits a short description of its own.
There are three subphyla under phylum Chordata. Two of these subphy1a are small, lack a vertebral column, and are of interest primarily as borderline or first chordates (protochordates,原索动物).
Subphylum Vertebrata (脊椎动物亚门):Bony or cartilaginous vertebrae surround spinal cord, notochord in all embryonic stages and persists in some of the fish.
脊椎动物是和人类关系最密切的一类动物
1 人类本身就是一类特殊的脊椎动物
2 脊椎动物和人类的衣食紧密相关
3 提供了丰富的中医药
4 提供了满足各种研究需要的实验动物
5 要保护的大多数动物都是脊椎动物
6 给人类也带来很多危害
二如何学好脊椎动物学
1以进化的观点来学****br/>2 形态特点和和生态环境紧密结合
3 理论教学和实验教学紧密结合
4 理论和实践紧密结合
5 以比较的方法来学****br/>进化地位
是所有动物中最高等的一门动物,包括尾索动物、头索动物和脊椎动物。
脊索动物由无脊椎动物演化而来,与棘皮动物和半索动物具有共同的祖先。
脊椎动物是神经系统获得最充分发展的动物,并由此最后演化出具有自我意识的人。
Characteristics of chordates(脊索动物的特征)
1) Notochord (a skeletal rod) present at some stage in life cycle
2) Nerve cord dorsal and tubular: anterior end of cord usually enlarged to form brain
3) Pharyngeal gill slits present at some stage in life cycle and may or may not be functional
4) A postanal tail usua1ly projecting beyond the anus at some stage and may or not persist
5) Deuterostome
6) Heart ventral, with dorsal and ventral blood vessels; closed blood system
7) Complete digestive system
8) Exoskeleton often present; well developed in some vertebrates
9) A cartilage or bony endoskeleton present in the majority of members (vertebrates)
10) Bilatera