三叶虫是距今5.6亿年前寒武纪最有代表性的远古动物。三叶虫长得十分奇特,身体分为头、胸和腹3个部分。背甲被两条背沟纵向分成大致相等的3片——一个轴叶和两个肋叶,因此被人们称为“三叶虫”。三叶虫最早是随着寒武纪初期一大批个体微小、低等的软体动物出现的。这些小动物给三叶虫带来了丰富的食源,而那时的海洋中,三叶虫还没有遇到有力的竞争对 Trilobite is 560 million years ago before the Cambrian most representative of ancient animals. Trilobite grows very strange, the body is divided into three parts, head and chest and abdomen. The carapace is divided longitudinally by two dorsal furrows into roughly three equal pieces - a shaft and two ribs, and is therefore called “trilobite.” Trilobite first with the early Cambrian period a large number of individual tiny, low molluscs appear. These small animals brought a rich source of food to the trilobites, and at that time the trilobites had not encountered strong competition