Summary:
- The animal kingdom is divided into more than 30 phyla.
- Table below lists the nine phyla with the greatest number of species.
- Each of the animal phyla listed in the table has at least 10,000 species.
- Invertebrates make up at least 95 percent of all animal species.
- Vertebrates are animals that have a backbone.
- All vertebrates belong to the phylum Chordata.
- They include fish, amphibians, reptiles, birds, and mammals.
- The last phylum, the Chordsata, also includes many invertebrate species.