EVERYDAY SCIENCE

Detailed explanation-1: -Most species within the phylum Chordata are vertebrates, or animals with backbones (subphylum Vertebrata). Examples of vertebrate chordates include fishes, amphibians, reptiles, birds, and mammals. A modern human-one species of mammal-is a familiar example of a chordate.

Detailed explanation-2: -The phylum chordata (animals with backbones) is divided into five common classes: fish, amphibians, reptiles, mammals and birds.

Detailed explanation-3: -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.

Detailed explanation-4: -Amphioxus also known as lancelet is a fish-like marine chordate. Unlike vertebrates, the dorsal nerve cord is not protected by bone but by a simpler notochord made up of a cylinder of cells that are closely packed to form a toughened rod.

Detailed explanation-5: -However, we share this phylum with two groups of invertebrates as well. Tunicates (subphylum Urochordata) and lancelets (subphylum Cephalochordata) are the only invertebrate groups within the phylum Chordata. Figure 3.97 shows some invertebrate representatives of the phylum Chordata.