NEET BIOLOGY

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: -Phylum Chordata belongs to the Kingdom Animalia and includes all the vertebrates, i.e., animals with a backbone, and several invertebrates, i.e., organisms without a backbone. They possess a bilaterally symmetrical body and are divided into three different sub-phyla.

Detailed explanation-3: -Chordates are divided into three subphyla: Craniata (fish, amphibians, reptiles, birds, and mammals); Tunicata or Urochordata (sea squirts, salps); and Cephalochordata (which includes lancelets). The Craniata and Tunicata compose the clade Olfactores, which is sister to Cephalochordata.

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.