Biology

Difference between chordates and non-chordates

Main difference

The main difference between chordates and non-chordates is that chordates are animals with a backbone, while non-chordates are animals without a backbone.

Chordates versus no chords

Kingdom Animalia is divided into different phyla according to the structure and cellular organization of the animals. So far, almost 30 phyla animals have been recognized. Animals like arthropods, mollusks, and annelids, etc. They are classified as Non-chordates. The main and last group of the animal kingdom is the Chordata phylum which includes parts, Birds and mammals, etc. Chordates are animals that have a notochord or backbone, while non-chordates are animals that do not have a backbone. Chordates are well-developed animals with well-developed body systems, while non-chordates are less-developed animals.

Comparative chart

Chordates No chordates
Animals that have a backbone are called chordates. Animals that do not have a backbone are called non-chordates.
Breathing
Chordates breathe through gills or lungs. Non-chordates breathe through the surface of the body, gills, or tracheae.
Body temperature
Chordates can be both cold-blooded and warm-blooded. The non-chordates are cold-blooded.
Notochord
The notochord is present at some point in the chordates or is replaced by a spinal column made up of ring-shaped vertebrae. Notochord or spinal column absent in non-chordates
Nervous system
Chordates have a hollow central dorsal nervous system. Non-chordates have a strong central nervous system.
Layers of germs
Chordates are triploblastic. Germ layers may be absent in non-chordates or they may be diploblastic or triploblastic.
Hemoglobin
In chordates, hemoglobin is present in red blood cells (RBC). Hemoglobin is present in plasma or absent in non-chordates
Celom
Chordates are truly coelomated. Non-chordates can be acellomate, pseudocoelomate, or truly coelomate.
Symmetry
The chordates are bilateral. The symmetry of the non-chordates can be radial, biradial, bilateral, or non-existent.
Metamerism (linear series of body segments)
Chordates have true metamerism. Non-chordates may have true or pseudo metamerism, or be absent.
Post-anal tail
The post-anal tail is usually present in chordates. The post-anal tail is absent in non-chordates.
Organization
They have a well developed organ system. They may or may not have an organ system.
Brain
Your brain is dorsal to the pharynx on the head. In non-chordates, the brain is absent or above the pharynx (if present).
Extremities
The limbs are derived from several chordate segments. The limbs are derived from the same segment in non-chordates
Bowel position
The intestinal position is ventral to the nerve cord in chordates. The intestinal position is dorsal to the nerve cord in non-chordates.
Year
In chordates, the anus differentiates and opens before the last segment. In non-chordates, the anus opens in the last segment or is absent.
Pharyngeal gill slits
Pharyngeal gill slits are present at some stage of life in chordates. Pharyngeal gill slits are absent in non-chordates.
Blood Vascular System
Chordates have a closed blood vascular system. The blood vascular system is absent in non-chordates and, if present, it may be open or closed.
Heart
The heart is placed ventrally in chordates. The heart is absent in non-chordates and if present it can be dorsal or lateral.
Nerve cord
In chordates, the nerve cord is single, dorsal, without ganglia. In non-chordates, the nerve cord is double, ventral, usually with ganglia.
Regeneration power
The power of regeneration is usually low in chordates. Regeneration power is usually good in non-chordates.
Skeleton
Both the exoskeleton and the endoskeleton are present in chordates. The only exoskeleton is present in non-chordates.
Examples
Hemichordata, Cyclostomata, Reptiles, Amphibia, Aves, and Mammals are examples of chordates. Protozoa, arthropods, annelids, etc. are examples of non-chordates.
What are chordates ?

The word “Chordate” is derived from the Greek word, ” chord” which means  cord or rope” and ” ata” means “bearing”. They have so far 49,000 species of which there are 2,500 species of amphibians, 9,000 birds, 4,500 mammals and around 6,000 reptiles. They range in size from medium to large, with the exception of the gigantic blue whale and the smallest fish. They are considered the largest and most ecologically successful group today. Chordates can occupy all types of habitat. They are found in the sea (marine), fresh water (aquatic), in the air (aerial) and on land (terrestrial), etc. from the poles to the equator. They have a notochord or spinal column and have well-developed body systems.

Subphilia of chordates

  • Urochordata: They are the chordates in which the notochord is present only in its larval tail.
  • Cephalochordata: In these chordates, the notochord extends from the head to the tail region throughout its life.
  • Vertebrata: In vertebrates, the notochord is present in its embryonic stage, which is replaced by a bony spinal column in the adult.

What are the non-chordates ?

The non-chordates also belong to the Animalia kingdom. They share many similarities and differences with chordates. They are less developed compared to chordates. They do not have well-developed body systems like the digestive system, the reproductive system, etc. In non-chordates, the notochord is absent and the pharynx is not perforated by gill slits. His heart is also in a dorsal position. They include phyla such as Porifera, Ctenophora, Platyhelminthes, Aschelminthes, Coelenterata (Cnidaria), Annelida, Arthropoda, Mollusca, and Echinodermata, etc.

ey differences

  1. Animals that have a backbone are called chordates, while animals that do not have a backbone are called non-chordates.
  2. Chordates breathe through the gills or lungs, on the other hand, non-chordates breathe through the body surface, gills, or windpipes.
  3. Chordates can be both cold-blooded and warm-blooded; on the contrary, the non-chordates are always cold-blooded.
  4. The notochord is present at some point in chordates or replaced by a spinal column made up of ring-shaped vertebrae on the other side, notochord or spinal column absent in non-chordates.
  5. Chordates have a hollow dorsal central nervous system, while non-chordates have a solid central nervous system.
  6. Chordates are triploblastic, whereas germ layers may be absent in non-chordates or they may be diploblastic or triploblastic.
  7. In chordates, hemoglobin is present in red blood cells (RBC), but hemoglobin is present in plasma or absent in non-chordates
  8. Chordates are truly coelomated, that is, they have a true body cavity, while non-chordates can be acellomate (no body cavity), pseudocoelomate (false body cavity), or truly coelomate.
  9. Chordates have bilateral symmetry, while non-chordates can be radial, biradial, bilateral, or without any symmetry.
  10. Chordates have true metamerism, but non-chordates can have true or pseudo metamerism or no metamerism.
  11. The posanal tail is usually present in chordates; on the other hand, the post-anal tail is absent in non-chordates.
  12. Chordates have a well-developed organ system, while non-chordates may or may not have an organ system.
  13. The brain of chordates is dorsal to the pharynx on the head, whereas in non-chordates the brain is absent or above the pharynx (if present).
  14. The extremities are derived from several segments in chordates, conversely, the extremities are derived from the same segment in non-chordates.
  15. The position of the intestine is ventral to the nerve cord in chordates, while the position of the intestine is dorsal to the nerve cord in non-chordates.
  16. In chordates, the anus differentiates and opens before the last segment, while in non-chordates, the anus opens in the last segment or is absent.
  17. Pharyngeal gill slits are present at some stage of life in chordates, while pharyngeal gill slits are absent in non-chordates.
  18. Chordates have a closed blood vascular system. While the blood vascular system is absent in non-chordates and if it is present it can be open or closed.
  19. The heart is placed ventrally in chordates, but the heart is absent in non-chordates and, if present, may be dorsal or lateral.
  20. In chordates, the nerve cord is single, dorsal, and without ganglia on the other side. In non-chordates, the nerve cord is double, ventral, and usually carries ganglia.
  21. Regeneration power is usually poor in chordates, while regeneration power is usually good in non-chordates.
  22. Both the exoskeleton and the endoskeleton are present in chordates, while the single exoskeleton is present in non-chordates.
  23. Hemicordates, Cyclostomes, Reptiles, Amphibians, Birds and Mammals are examples of chordates, while protozoa, arthropods, annelids, etc. are examples of non-chordates.
Final Thought

From the above discussion, it is summarized that both chordates and non-chordates belong to the Animalia Kingdom. Chordates are well-developed animals with adequate body systems and spinal column or notochord present, while non-chordates are less developed compared to chordates and have no notochord.

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