zuo 2 - 副本.doc

脊椎动物的起源与演化证据
谭飞
(湖北省长江大学地球科学学院,荆州
434023)
摘要:脊椎动物的起源历来是进化生命科学的核心命题,包括人类在内的脊椎动物谱系总根底起源,涉及到脊椎动物两大类群间的演化关系,因而不仅是学术界长期探索的一个焦点问题,也是大众普遍关注的一个科学热点。近年来脊椎动物的起源与演化有重大突破。云南澄江寒武纪化石群中的发现的大量化石如昆明鱼(Myllokunmingia)和海口鱼(Haikouichthys),郝氏地大动物(Dazoonhaole Shu&Hart,2001)等论证了普通无脊椎动物向脊椎动物演化过渡的各种中间类型,勾勒出一幅较为完整的早期生命演化谱系。西北大学早期生命研究所舒德干教授基于对靠近脊椎动物“源头”时段软躯体后口动物化石系列的研究以及新的发现提出脊椎动物起源分“五步走”的新假说[3]。在此研究基础上人们也慢慢的对于脊椎动物从低级的鱼形超纲到四足超纲的演化历程有了更清晰的认识。从水生的原始鱼类到水陆过渡的两栖纲,到爬行纲,到对飞行适应最好的鸟纲,最高等的脊椎动物哺乳纲,一幅完整的进化树形态慢慢揭示开来。
本文即在前人研究的基础上,结合自己的一些认识综述了脊椎动物的起源以及演化证据的研究进展。
关键词:脊椎动物;起源与演化;证据;进化树
Evidence of Vertebrate Origin and Evolvement
Fei Tan
(School of Earth Scienc,Yangtze University,Jingzhou,434023,China)
Abstract:The vertebrate origin and evolvement has always played core role of evolution and life total basic origin of vertebrate lineages including humans, involves the evolution relationship between two vertebrate groups, which is not only a focus issue long-term exploration in academic circles, but a scientific focus is mon concern of the ,there have been vital advances in vertebrate origin and evolvement. Some original fossils such as Myllokunmingia and Haikouichthys, Didazoonhaoae Shu&Han,2001 had been found in Yunnan Chengjiang Cambrian fauna and have been being investigated by many scholars. This demonstrates that these fossils are intermedial transitional types that evolved from invertebrate to vertebrate. Therefore, paratively integrated evolutivc tree was described. D-G Shu in early life institute of Northwest University proposed the hypothesis that there were five steps in vertebrate origin based upon series of investigations concerning metazoan soft-body fossils closed vertebrate a clearer understanding of origin and evolvement on the basis of this study, people also slowly in vertebrates from Pisces to Tetrapoda, from aquatic raw fish to water transition of Amphibia,
from Reptilia to the best adaptation for flight Aves, to Mammalia highest