the middle zone of the mesoderm of a chordate vertebrate embryo, from which excretory tissue develops.
中胚叶节脊索类脊椎动物胚胎的中胚层的中间部分,…
the origin of vertebrates has always been a core question in evolutionary biology. it is well accepted that vertebrates and invertebrate chordate derived from a common ancestor.
脊椎动物的起源是进化生物学研究的核心问题之一,目前人们普遍认为脊椎动物与无脊椎动物中的脊索动物起源于同一个原始祖先。
instead, they are the result of what happens when you fuse an ancient chordate with the ancestor of a sea urchin .
与此相反,海鞘是古代的脊索动物和海胆的祖先结合在一起时所产生的结果。
beginning. this genus is considered a chordate , and the phylum chordata includes fish, mammals and man.
的注意。因为这一类动物属于最高的脊索或半脊索动物,包括鱼类,哺乳类动物和人。