A four-chambered heart separates oxygenated blood coming from the lungs from the partially deoxygenated blood that heading back to the lungs to be re-oxygenated. Fish vs. Therapsids were quadrupedal and had such mammalian features as specialized tooth structures and an opening in the temporal region of the skull. Those that did not stayed as fish. At the end of the lesson, students will be able to identify Mammals, Birds, Fish, Reptiles, and Amphibians; compare and contrast the differences and give examples of each animal … A snake is an animal that belongs to a group of animals called reptiles, but there are four main groups of reptiles: turtles and tortoises, lizards and snakes, crocodiles and alligators, and the tuatara. The reptile is also a cold blooded animal that is covered by scutes or scales. Although amphibian gastrulation is considerably modified in comparison with that in animals with oligolecithal eggs (e.g., amphioxus and starfishes), an archenteron forms by a process of invagination.Such is not the case, however, in the higher vertebrates that possess eggs with enormous amounts of yolk, as do the reptiles, birds, and egg-laying mammals. Fish also have scales, although they are absent in cartilaginous fish. Well fish are actually unevolved reptiles. Reptiles were the first true terrestrial chordates. References for alligators. However, only mammals and birds possess four-chambered hearts, which are more efficient than the two-chambered hearts of fish or the three-chambered hearts of amphibians and reptiles. Unlike their predecessors, their bodies and the shells of their eggs were well adapted to withstand desiccation and they did not have the obligation to live close to water to ensure successful reproduction. Some species of fish later evolved into amphibians, and some amphibians evolved into reptiles. Well fish were among the first multicellular animals created, and then they evolved legs to become reptiles. Mammals evolved from a group of reptiles called therapsids, which lived from 299 million to 200 million years ago. The bird group is one of six basic animal groups, with the others being amphibians, fish, invertebrates, mammals and reptiles. General classification categories fish as the first vertebrates to appear on the planet. They lay eggs and have lightweight bones. Reptiles and Mammals are two important classes of the phylum chordata. Birds have a high metabolic rate and a four-chambered heart. Mammals, birds and fish are among evolution’s "winners," while crocodiles and other reptiles have ended up on the losing end, a new study suggests. Alligators are unusual among reptiles in having a complete secondary palate. Reptiles, birds, and mammals. Students are also asked to look at a list of animals and tell whether each is a mammal, fish, bird, reptile, or amphibian. Reptiles have lived on Earth for hundreds of millions of years. A fish is an aquatic vertebrate that is cold blooded or ectothermic. They were most likely warm-blooded. Some of the animals we see today evolved from entirely different animals 65 million years ago. When classifying you may call fish invertebrates, but after that they can only be classified specifically as fish. The earliest known reptiles originated about 340 million years ago. In general, fish, amphibians and most reptiles lack a solid bony secondary palate, while mammals all have it. AS you may know, all life began in the water. A number of distinct characteristics can be found in birds, beyond having feathers. A fish is an animal that lives only in the water, whereas a reptile lives in both land and water. The fish is akin to the groups you've listed as 'mammal' and 'reptile' so you would say that a sailfish is a type of fish. For comparison, look at the skulls of a frog, salamander, gila monster, and bird. Snake A horse is a type of mammal and a lizard is a type of reptile. Reptiles. Alligator skeleton from Udo Savalli at ASU.