The jawless fish, the bony fish, all reptiles, all birds and all mammals are all examples of animals found in the phylum Chordata. This phylum is extremely diverse and contains approximately 43,700 species.
The phylum Chordata contains all animals that either contain or have contained a hollow nerve cord and a notochord. Most animals found in this phylum had a notochord sometime during their development, which then grew into a spinal cord. This phylum is divided into three different subtypes: Urochordata, Cephalachordata and Vertebrata. Due to its massive number of subtypes, this phylum is the third-largest phylum in the entire animal kingdom.