Characteristics of Vertebrates

Vertebrates are members the the subphylum Vertebrata, under the phylum Chordata and also under the kingdom Animalia. Animals that possess bilateral symmetry can be split into two groups, protostomes and also deuterostomes, based upon their trends of embryonic development. The deuterostomes, who name equates as “second mouth,” consists of two phyla: Chordata and also Echinodermata. Echinoderms room invertebrate marine pets that have actually pentaradial symmetry and a spiny body covering; the phylum contains sea stars, sea urchins, and sea cucumbers. The phylum Chordata contains two teams of invertebrate chordates, but the most conspicuous and familiar members that Chordata space the vertebrates.

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Figure \(\PageIndex1\): Phylum chordata: every chordates space deuterostomes, own a notochord. Vertebrates are identified by having a vertebral column.

As chordates, all vertebrates have a similar anatomy and also morphology v the exact same qualifying characteristics: a notochord, a dorsal hollow nerve cord, pharyngeal slits, and also a post-anal tail. However, the subphylum Vertebrata is differentiated from the phylum Chordata by the breakthrough of the notochord into a bony backbone. Vertebrates encompass the amphibians, reptiles, mammals, and birds, and also the jawless fishes, bony fishes, sharks, and also rays.

Figure \(\PageIndex1\): Diversity of vertebrates: animals with backbones: The subphylum Vertebrata includes all pets that possess backbones, gills, and also a main nervous system in at the very least one phase of development. Vertebrates incorporate amphibians, reptiles, mammals, and also birds, as well as the jawless fishes, bony fishes, sharks, and rays.

More 보다 64,000 varieties of vertebrates have been described, yet the extant vertebrate varieties represent only a small section of every the vertebrates that have existed. Vertebrates range in dimension from the frog types Paedophryne amauensis (as tiny as 7.7 mm (0.3 inch)) to the blue whale (as huge as 33 m (110 ft)). Vertebrates comprise around 4 percent of all described animal species; the remainder space invertebrates, which absence backbones.




The Vertebral Column

Vertebrates are characterized by the visibility of the vertebral column. In vertebrates, the notochord develops into the vertebral column or spine: a collection of bony vertebrae every separated through mobile discs. These vertebrae are constantly found ~ above the dorsal next of the animal. However, a couple of vertebrates have actually secondarily shed their vertebrae and, instead, retain the notochord right into adulthood (e.g., the sturgeon fish).

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Figure \(\PageIndex1\): Vertebral column: A fossilized skeleton of the dinosaur Diplodocus carnegii shows an extreme example that the backbone the characterizes vertebrates.