Chordata

例句：

1. 1. The discovery of the fossils in the cave has led to a new understanding of the evolution of vertebrates.
   洞穴中的化石发现促使人们重新理解了脊椎动物的进化。
2. 2. Many scientists believe that vertebrates are the first animals to have developed complex nervous systems.
   许多科学家认为，脊椎动物是最早发展出复杂神经系统的动物。
3. 3. Vertebrates are classified into several groups based on their physical characteristics and evolutionary history.
   根据其物理特征和进化历史，脊椎动物被分为几个不同的类别。