后生动物 (metazoa) 属于动物类，虽然在最早期的化石研究纪录里显示在埃迪卡拉纪时代的水母(刺细胞动物 Cnidaria)已经出现，但是海绵(海绵动物 Porifera)有可能比水母还要更早进化。 (依据化石的研究纪录) 大多数已被矿化的动物门类之骨骼首先出现在寒武纪时期, 其年代已超过 5亿年之久，而且还有另一种听似有理的说词，多数的生物门可能在寒武纪生物爆发 (Cambrian explosion) 时已经进化，但是并没有留下任何化石记录。凯文・彼得森认为最早期的后生动物大概出现在5亿7300-6亿5600万年前。
友谊网页连结
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The Museums of Cape Town have a marvelous introduction to the kingdom of animals (Metazoa) with photographs and descriptions of the various phyla.
- A page from U Cal Berkeley about the Metazoa fossil record suggests it may be possible that nearly all the phyla of metazoa evolved in the Cambrian aside from
the Cnidaria, which evolved earlier, in the Ediacaran (Vendian).
- Were the Cnidaria present in the Ediacaran Era, or did they evolve later, in the Cambrian. This article from the New York Times discusses fossil and DNA evidence that seem to suggest conflicting dates for Cnidaria (600 MYA or 540 MYA).
- The Museum Victoria in Australia has a page about the oldest evidence of life, including the earliest animal life.
- Another possible ancestor of early metazoa would be the bilaterians who lived 580-600 million years ago.
后生动物 (metazoa) 属于动物类，虽然在最早期的化石研究纪录里显示在埃迪卡拉纪时代的水母(刺细胞动物 Cnidaria)已经出现，但是海绵(海绵动物 Porifera)有可能比水母还要更早进化。 (依据化石的研究纪录) 大多数已被矿化的动物门类之骨骼首先出现在寒武纪时期, 其年代已超过 5亿年之久，而且还有另一种听似有理的说词，多数的生物门可能在寒武纪生物爆发 (Cambrian explosion) 时已经进化，但是并没有留下任何化石记录。凯文・彼得森认为最早期的后生动物大概出现在5亿7300-6亿5600万年前。
友谊网页连结
- The Museums of Cape Town have a marvelous introduction to the kingdom of animals (Metazoa) with photographs and descriptions of the various phyla.
- A page from U Cal Berkeley about the Metazoa fossil record suggests it may be possible that nearly all the phyla of metazoa evolved in the Cambrian aside from
the Cnidaria, which evolved earlier, in the Ediacaran (Vendian).
- Were the Cnidaria present in the Ediacaran Era, or did they evolve later, in the Cambrian. This article from the New York Times discusses fossil and DNA evidence that seem to suggest conflicting dates for Cnidaria (600 MYA or 540 MYA).
- The Museum Victoria in Australia has a page about the oldest evidence of life, including the earliest animal life.
- Another possible ancestor of early metazoa would be the bilaterians who lived 580-600 million years ago.