Chordata

Chordata belongs to the type of three-layer multicellular animals - vertebrates, combining 3 subtypes: 1) jawless - lamprey and hagfish; 2) gnathostomes (tadpoles). Representatives of these subtypes had a common ancestor and evolved on the territory of the former Gondwana continent, now called the “basalt” or “Afar lagoons”; 3) cranial (cephalopods), the main representatives of this subtype are sharks and rays. All chordates form an inner ear, a bony skeleton, and nerve ganglia on the ventral side of the body, characterized by a high ability for differentiation and specialization, which allowed chordates in the process of evolution to create new forms, including Homo sapiens. Key