All vertebrates, including frogs, are animals with backbones. Frogs have many biological features in common with other members of the subphylum Vertebrata, a taxonomic grouping that also includes fish, birds and human beings.
All vertebrates have bone, cartilage, paired eyes, a circulatory system with a centralized heart, and a mouth and pharynx with muscles. Compared to other organisms in the animal kingdom, vertebrates have more highly developed brains.
The presence of neural crest cells characterizes all vertebrates. At the embryonic stage, neural crest cells emerge inside the vertebrate, migrate to various parts of the body and control the development of a diverse range of cells. Neural crest cells influence, among other things, the shape of the facial skeleton, skin pigment and the peripheral nervous system.
All vertebrates at some point in their development have a post-anal tail. However, many vertebrates, such as frogs and human beings, do not carry this tail to maturity. Other characteristics present in at least one early stage of all vertebrates' life cycles are the notochord, dorsal nerve cord and pharyngeal slits. The notochord is a rod that runs the length of an organism. It transforms into a component of many mature vertebrates' spinal columns. The dorsal nerve cord runs along the back of an organism. The dorsal nerve cord eventually becomes the brain and central nervous system in the mature vertebrate. The pharyngeal slits are openings between the pharynx and the throat on the exterior of the organism.