Chordata

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Chordata

 [kor-da´tah]
a phylum of the animal kingdom comprising all animals having a notochord during some developmental stage.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.

Chor·da·ta

(kor-dā'tă),
The phylum that includes the vertebrates, defined by possession of: 1) a single dorsal nerve cord (the brain and spinal cord of mammals); 2) a cartilaginous rod, the notochord, which forms dorsal to the primitive gut in the early embryo, and is surrounded and replaced by the vertebral column in the subphylum vertebrata; and 3) by presence at some stage in development of gill slits in the pharynx or throat.
[L. chorda, fr. G. chordē, a string]
Farlex Partner Medical Dictionary © Farlex 2012

Chor·da·ta

(kōr-dā'tă)
The phylum that includes the vertebrates, defined by possession of 1) a single dorsal nerve cord (the brain and spinal cord of mammals); 2) a cartilaginous rod, the notochord, which forms dorsal to the primitive gut in the early embryo and is surrounded and replaced by the vertebral column in the subphylum vertebrata; and 3) the presence at some stage in development of gill slits in the pharynx or throat.
[L. chorda, fr. G. chordē, a string]
Medical Dictionary for the Health Professions and Nursing © Farlex 2012
References in periodicals archive ?
Collectively, these data suggest that osmoregulatory activities of GH already emerged in the basal chordate [37], much earlier than thought before [38].
coli, the chromosomes of a chordate, the mind of humans, or the hand of God.
(2007) Ascidian embryonic development: an emerging model system for the study of cell fate specification in chordates. Dev.
They found that the cells form a muscle that runs along the animal's midline, precisely where the notochord would be if the worm were a chordate. The researchers named this muscle the axochord, as it runs along the animal's axis.
"Work from my lab has shown that enteropneusts filter feed using a pharynx perforated with gill slits, just like the invertebrate chordates" stated Cameron.
Another characteristic of chordates are myomeres, blocks of muscle tissue often arranged in a zig-zag pattern.
Chapters on Simple Animals, Cnidarians, Flatworms and Roundworms, Segmented Worms, Mollusks, Arachnids, Crustaceans, Centipedes and Millipedes, Insects, Echinoderms, Chordates, Cartilaginous Fish, Bony Fish, Amphibians, Reptiles, Birds and Mammals are included, along with a Glossary and index.
In addition, many students have never learned about the subphylum Urochordata (sea squirts/tunicates) and are under the mistaken impression that all chordates have a back bone.
I used a PowerPoint presentation with photographs of algae, protozoa (single celled organisms - star forams are found on Lord Howe), sponges, cnidaria (sea jellies, sea anemones, coral, bryozoans), Molluscs (sea snails and sea slugs, clams, cuttlefish), Echinoderms (sea stars, sea urchins, brittle stars, feather stars, basket stars), Arthropods (hermit crabs, coral banded shrimp, anemone shrimp, painted crayfish), Chordates including those without backbones - Ascidians (yes there is such a thing), and those with back bones - Sharks and Rays, Fish, Turtles, Birds and Mammals (Lord Howe has Dolphins and gets the odd Whale shark or other whales passing by).
They also remain a neglected component relative to the far less diverse chordates (64,788 species) and plants (297,857 species), with 75 %<> of the 18,000 new species described in 2007 being invertebrates and an estimated 5,396,465 invertebrate species still remaining to be described globally (Chapman 2009).
The five phyla that include the highest number of animal species are the nematodes, or round worms; annelids, or ringed worms; mollusks; the arthropods; and chordates. These phyla, in turn, are divided into classes and each class then is subdivided into orders, families, genera, and species.