Chordate facts for kids

Quick facts for kids Chordates Temporal range: Late Ediacaran – Present
A X-ray tetra is one of the few chordates with a visible backbone
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Subkingdom:	Eumetazoa
Superphylum:	Deuterostomia
Phylum:	Chordata Bateson, 1885
Typical Classes
See below

Chordata is a phylum (group) of animals which have a notochord. The group includes vertebrates, with some closely related invertebrates.

Classification

Taxonomy

• Phylum Chordata
  • Tunicata – (tunicates, formerly Urochordata; 3,000 species)
  • †Vetulicolia (8 Cambrian species of fossil)
  • Cephalochordata – (lancelets, 30 species)
  • Vertebrata (vertebrates – animals with backbones; 57,739 species)
    • Agnatha (jawless vertebrates; 100+ species)
      • Myxini or Hyperotreti (hagfish; 65 species)
      • Conodonta (Conodonts)
      • Hyperoartia (Lampreys)
      • †Cephalaspidomorphi (Paleozoic jawless fish)
      • †Pteraspidomorphi (Paleozoic jawless fish)
    • Gnathostomata (jawed vertebrates)
      • †Placodermi (Paleozoic armoured forms)
      • Chondrichthyes (cartilaginous fish; 300+ species)
      • †Acanthodii (Paleozoic "spiny sharks")
      • Osteichthyes (bony fishes; 30,000+ species)
        • Actinopterygii (ray-finned fish; about 30,000 species)
        • Sarcopterygii (lobe-finned fish)
      • Tetrapoda (four-legged vertebrates; 18,000+ species)

Phylogeny

Note: Lines show likely evolutionary relationships. Extinct groups are marked with a "†". Extinct animals are ones that have completely died out.

Origin of chordates

According to a long-standing theory, the origin of chordates may be found in transformed larvae of sea-squirts (tunicates). Adult tunicates are sessile, but their larvae are motile, and have some features found in early vertebrates. The process of paedomorphosis, where juvenile features are retained in the adult, is the proposed mechanism. Genome analysis shows that tunicates are the closest living relatives of vertebrates.

Images for kids

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  The glass catfish (Kryptopterus vitreolus) is one of the few chordates with a visible backbone. The spinal cord is housed within its backbone.

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  Cephalochordate: Lancelet

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  Tunicates: sea squirts

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  Craniate: Hagfish

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  Haikouichthys, from about 518 million years ago in China, may be the earliest known fish.

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  A skeleton of the blue whale, the largest animal, extant or extinct, ever discovered, outside the Long Marine Laboratory at the University of California, Santa Cruz. The largest blue whale ever reliably recorded measured 98ft (29.9m) long.

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  A peregrine falcon, the world's fastest animal. Peregrines utilise gravity and aerodynamics to achieve their top speed of around 242mph (389km/h), as opposed to locomotion.

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  Acorn worms or Enteropneusts are example of hemichordates.

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  A red knob sea star, Protoreaster linckii is an example of Asterozoan Echinoderm.

See also

In Spanish: Chordata para niños