What is the difference between chordates and non-chordates?
Kingdom Animalia is further divided into certain phyla and classes. An organism that belongs to this kingdom has different patterns of cell organization. This helps to tell the difference between a lower organism and higher organisms.
The core difference between chordates and non-chordates is that chordates are animals that have a backbone in their body structures while non-chordates are animals without backbones or notochords.
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What Are Chordates?
Chordates are animals with chords or backbone in their body structures. There are about 49,000 species of animals with backbones.
The body size of chordates tends to vary in size of either medium or large. These organisms tend to occupy a large ecological niche.
These organisms can be found on land, marine water, freshwater, and in the air. They can either be cold-blooded or warm-blooded animals.
What are Non-Chordates?
Non-chordates are animals that lack backbone or notochords. These organisms tend to lack developed body systems such as reproduction and digestive systems.
Examples of animals without notochords are Porifera, Ctenophora, Platyhelminthes, Aschelminthes, Coelenterata (Cnidaria), Annelida, Arthropoda, Mollusca, and Echinodermata.
Comparison Chart: Chordates vs Non-Chordates
| Basic Terms | Chordates | Non-Chordates |
| Meaning | These are organisms with backbones | These are organisms without backbones |
| Respiration | Through gills or lungs | Through the body surface, gills, or tracheae |
| Body temperature | Either cold or warm-blooded | Only cold-blooded |
| Notochord | Tend to be present at some stage and get replaced by backbone | Lack of both notochord and backbone |
| Nervous system | Tend to have a hollow central dorsal nervous system | Tend to have a solid central nervous system |
| Germ Layers | Triploblastic | Either diploblastic or triploblastic |
| Hemoglobin | Present in the red corpuscles (RBC) | Present in the plasma |
| Coelom | Truly coelomate | Either acoelomate, pseudocoelomate, or truly coelomate |
| Symmetry | Bilateral | It May be radial, biradial, bilateral or lacking |
| Metamerism | Have true Metamerism | Have pseudo metamerism |
| Post-Anal Tail | Present | Absent |
| Organization | Well-developed organs and systems | Lack of developing organ system |
| Brain | Tend to be dorsal to pharynx in the head | Absent or above the pharynx if present |
| Limbs | Derived from several segments | Derived from the same segment |
| Gut Position | Ventral to the nerve cord | Dorsal to the nerve cord |
| Anus | Open before the last segment | Open on the last segment |
| Pharyngeal Gill-Slits | Are present at some stage | Absent |
| Blood Vascular System | Have a closed vascular system | Have open vascular system if present |
| Heart | Ventrally placed | Dorsally or lateral if present |
| Nerve Cord | Tend to be single and dorsal without ganglia. | Tend to be double and ventral usually bearing ganglia |
| Regeneration Power | Tend to be poor | Tend to be good |
| Skeleton | Have both endoskeleton and exoskeleton | Have exoskeleton only |
| Examples | Hemichordata, Cyclostomata, Reptiles, Amphibia, Aves, and Mammals | Protozoa, Arthropods, Annelids, |
Core Differences between Chordates and Non-Chordates In Point Form
- Chordates have chord or backbone while non-chordates lack backbone
- Chordates have a hollow central dorsal nervous system whereas non-chordates have a solid central nervous system.
- Chordates have either cold or warm-blooded while non-chordates are cold-blooded
- Chordates respire through lungs or gills while non-chordates respire through the body surface and gills
- Chordates have a germ layer while non-chordates lack a germ layer
- Chordates have hemoglobin present in the red blood cells while non-chordates present in the plasma
- Chordates have true coelomate while non-chordates have either acoelomate, pseudocoelomate, or truly coelomate.
- Chordates have bilateral symmetry while non-chordates may be radial, biradial, and bilateral.
- Chordates have true metamerism while non-chordates have pseudo metamerism
- Post anal tail is present in chordates while absent in non-chordates
- Chordates have a well-developed organ system while non-chordates have a poorly developed organ system
- The brain of chordates are dorsal to the pharynx in the head while absent in non-chordates
- Chordates derived their limbs from several segments while non-chordates from the same segment
- The gut position of chordates is ventral to the nerve cord while that of non-chordates is dorsal to the nerve cord
- The anus of chordates is differentiated and opens before the last segment while that of non-chordates opens on the last segment
- Pharyngeal gill slits are present in chordates while absent in non-chordates
- Chordates have closed vascular system while non-chordates have both open and closed
- Chordates have ventrally placed heart while non-chordates have a dorsal or lateral placed heart if present
- The nerve cord of chordates are single and dorsal while that of non-chordates are double and ventral
- The regeneration power of chordates are poor while that of non-chordate are good
- Chordates have both exoskeletons and endoskeletons while non-chordates have the only exoskeleton
- Examples of chordates are Hemichordata, Cyclostomata, Reptiles, Amphibia, Aves, and Mammals while those of non-chordates are Protozoa, Arthropods, and Annelids.
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Comparison Video
Summary
Chordates are animals marked by the presence of backbone while non-chordates are animals without backbone or notochord. Chordates are animals with both endoskeleton and exoskeleton while non-chordates have only exoskeleton