Main vertebrate groups

As we discussed there are main groups under vertebrates. Let us consider each one of them. 1. Pisces 2. Amphibia 3. Reptilia 4. Aves 5. Mammalia Pisces Pisces is a category of organisms that includes all types of fish. Pisces are vertebrates. They have specific organs for processes such as blood circulation, excretion, respiration, locomotion, etc. Pisces are poikilotherms. They do not have the ability to regulate their own body temperature.

Amphibia Amphibians are a class of animal that represents a crucial evolutionary step between water-dwelling fish and land-dwelling mammals and reptiles. They are among the most fascinating (and rapidly dwindling) animals on earth. Unlike most animals, amphibians such as toads, frogs, newts, and salamanders finish up much of their final development as an organism after they are born, changing from marine-based to land-based lifestyles in the first few days of life.

Reptilia This class includes today’s turtles, crocodilians, snakes, amphisbaenians, lizards, tuatara, and their extinct relatives. The study of these traditional reptile orders, historically combined with that of modern amphibians, is called herpetology.

Aves Aves is a taxonomic class of birds. The class belongs to the phylum Chordata (chordates). Some of their common features: oviparous reproduction, complete double circulation, wings (modified front limbs), feathers, and beak without teeth (except for some Mesozoic fossil birds that have conical teeth in both jaws).

Mammalia Mammalia,any member of the group of vertebrate animals in which the young are nourished with milk from special mammary glands of the mother. In addition to these characteristic milk glands, mammals are distinguished by several other unique features. Hair is a typical mammalian feature, although in many whales it has disappeared except in the fetal stage. The mammalian lower jaw is hinged directly to the skull, instead of through a separate bone (the quadrate) as in all other vertebrates. A chain of three tiny bones transmits sound waves across the middle ear. A muscular diaphragm separates the heart and the lungs from the abdominal cavity. Only the left aortic arch persists. (In birds the right aortic arch persists; in reptiles, amphibians, and fishes both arches are retained.) Mature red blood cells (erythrocytes) in all mammals lack a nucleus; all other vertebrates have nucleated red blood cells.