Final answer:
The term for four-limbed animals is tetrapods, encompassing amphibians, reptiles, birds, and mammals, grouped together because of their shared evolutionary history.
Step-by-step explanation:
The term that refers to four-limbed animals is tetrapods. The term "tetrapod" denotes a significant group in the evolutionary history, consisting of animals such as amphibians, reptiles, birds, and mammals. These creatures are unified by having an evolutionary history that includes the development of four limbs.
Tetrapods are a subset of gnathostomes, or "jawed mouth" animals, and they range from the earliest four-limbed vertebrates to various land-dwelling species observed today. Some tetrapods have limbs that have evolved for diverse functions beyond walking, like the fins of aquatic mammals. Notably, the early tetrapods such as Ichthyostega and Acanthostega were aquatic and had limbs incapable of supporting their bodies well out of water.
Interestingly, while snakes and some other reptiles lack visible limbs, they are still classified as tetrapods due to their descent from four-limbed ancestors. This classification highlights the importance of phylogenetic relationships over current morphology in defining such evolutionary groups.