Jasmine Grover Content Strategy Manager
Content Strategy Manager
Animal Kingdom categorizes living organisms on Earth into certain groups having unique characteristics. In the animal kingdom, one of the main ways we classify creatures is by whether they have a notochord. This rod-like structure, made of cartilage or flexible tissue, plays a crucial role in the development and support of the body.
- Therefore, a notochord is like a flexible cartilage rod
- Animals can be divided into two main groups:
Thus, the main point of difference between chordates and non-chordates is that chordates have a backbone (notochord), while non-chordates lack this defining feature. In this article, we will cover the differences between chordates and non chordates and understand their characteristics.
Download: Difference between chordates and non-chordates PDF notes
Key terms: Chordates, Non-chordates, Animals, Notochord, Nerve Cord, Kingdom Animalia, Phylum
Difference Between Chordates and Non-Chordates
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The presence of notochord mainly differentiates chordates and Non-chordates. Other differences between non chordates and chordates are as given below –
| Chordates | Non-Chordates |
|---|---|
| Chordates are animals with a notochord or backbone in their body structure. | Non-chordates are animals that lack a notochord. |
| They have two pairs of limbs. | They may have more than two pairs of limbs. |
| The heart is ventrally placed with RBC, haemoglobin and limbs. | The heart is in a dorsal or lateral position with limbs |
| Examples – Frogs, fish, birds, reptiles, amphibians, and mammals. | Examples – Cockroaches, earthworms, flatworms, jellyfish, sponges, etc. |
| Post-anal tails are present in chordates. | Post-anal tails are absent in non chordates. |
| A closed Circulatory System is present. | Open blood circulation is there. |
| Chordates have a dorsal and hollow nerve cord that is devoid of ganglia. | A central and double nerve cord is present with ganglia present. |
| They have pharyngeal gill slits. | The pharyngeal gill slits are absent. |
| Chordates breathe through the gills or the lungs. | Non chordates breathe through their trachea, gills, or body surface. |
| Hemoglobin is present. | Instead of haemoglobin, hemolymph is present, which is comparable to blood. |
| With respect to the germ layer, they are triploblastic | They are diploblastic, Triploblastic, or neither |
| Bilaterally Symmetric. | Bilateral, bi-radial, asymmetrical, or radial. |
| True Coelomates | True coelomates, acoelomates, and pseudocoelomates are all possible. |
| Exoskeletons are found in some chordates, such as tortoises. | Exoskeleton is present in all non chordates. |
| The endoskeleton is present in all chordates. | All non chordates do not have endoskeletons. |
| Poor regeneration | Good regeneration is present in mostly non-chordates. |
| These animals' anus is distinct and open before the last section. | The anus is usually absent in these animals, and if it is present, it opens in the last segment. |
| The chordate brain is present and is positioned dorsal to the pharynx in the head. | If present in certain animals, the brain is not as complex as that of chordates. |
| They have a body that includes an organ system. | The organization is protoplasmic to the organ system. |
Also Check:
| Other Concepts | ||
|---|---|---|
| Five kingdom classification | Animal tissues | Kingdom Monera |
| Genetic Engineering | Scientific Name of Pigeon | Components of Ecosystem |
| Mycology | Ascomycetes | Sexual Reproduction in Fungi |
Chordates
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Chordates are animal bodies with a notochord present anywhere in their bodies. Pharyngeal gill slits and a hollow nerve cord distinguish this group.
- The presence of a notochord provides support and structure during development.
- The nerve cord runs along the back of the body, enclosed by the notochord.
- Chordates have slits in their throats, used for respiration in some stages of life.
- Most chordates exhibit bilateral symmetry, with mirror-image halves on either side of a central axis.
- All chordates are vertebrates, meaning they have a backbone that develops from the notochord.
- Chordates are complex, cold-blooded or warm-blooded, and have a true coelom (body cavity).
- They have a post-anal tail for balance, and some have an exoskeleton or endoskeleton.
- Their digestive system can be complete or incomplete, with the gut below the nerve cord.
- Aquatic chordates breathe through gills, while land dwellers use lungs, and some like amphibians can breathe through their skin.
- Examples: Fish, amphibians, reptiles, birds, and mammals.
Non Chordates
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Non-chordates are animals that lack the rod-like structure known as the notochord in their bodies.
- They display more diverse body symmetries than chordates.
- Non-chordates can be cold-blooded, with varying gut and germ layer complexity.
- They are essentially pseudocoelomate, coelomate, triploblastic, or cylindrical creatures.
- Unlike chordates, they lack both a post-anal tail and an endoskeleton.
- Non-chordates boast impressive regeneration abilities and organize from protoplasm to organ systems.
- Their gut sits above the nerve cord, typically missing an anus or placing it at the last segment.
- They breathe through diffusion across the body, lacking gill slits.
In the animal kingdom, the presence or absence of a defining structure – the notochord – separates two major groups: chordates and non-chordates. Chordates, including vertebrates like fish and mammals, possess this flexible rod-like structure that provides support and forms the backbone. Non-chordates, including invertebrates like insects and worms, lack this feature and exhibit a wider variety of body plans and symmetries. Additionally, chordates have dorsal nerve cords, pharyngeal gill slits, and typically bilateral symmetry, while non-chordates have diverse gut and germ layer arrangements, and exoskeletons, and breathe through diffusion. Overall, the presence of a notochord marks a fundamental difference, paving the way for the complex nervous system, efficient respiratory systems, and diverse adaptations that characterize the successful lineage of chordates.
Also Check:
Things to Remember
- Chordates and non-chordates are the two main groups of the Animal kingdom characterised by the presence or absence of notochord.
- Chordates such as fish and mammals are defined by a flexible rod (notochord) that becomes a backbone.
- Non-chordates such as insects and worms lack the notochord and showcase diverse body shapes and symmetries.
- Chordates have dorsal nerve chords (brain-to-tail cable), while it is absent in non-chordates.
- Pharyngeal gill slits are unique to chordates, these slits aid breathing at some stage of life.
- Non-chordates have simpler gut and germ layer arrangements compared to chordates.
- Diffusion across the body surface for non-chordates, gills or lungs for chordates.
- Notochord leads to complex nervous systems in chordates and varied adaptations.
Previous Year Questions
- In the classification of plants, the term cladistics refers to the (KEAM)
- The heterosporous pteridophyte belonging to the class lycopsida is (KEAM)
- The antherozoids of Funaria are (NEET 1999)
- Select the correct statement (NEET 2016)
- Dichotomous branching is found in (NEET 1999)
- Scyphozoan medusae are commonly known as (COMEDK UGET 2010)
- External fertilization occurs in majority of (DUET 2009)
- Tetradynamous conditions occur in (NEET 2001)
- The correct sequence of taxonomic hierarchy is (KCET 2018)
- Read the statements given below and identify the incorrect statement (KCET 2012)
- Reason of diversity in living beings is (NEET 2001)
- Which of the following pairs of specific names belongs to the same common genus?
- Moss peristome takes part in (NEET 1990)
- In which of the following animals post anal tail is found? (NEET 2001)
- Engler and Prantl published a phylogenetic system in the monograph (KEAM)
Sample Questions
Ques. Do non-chordates have any special abilities? (2 Marks)
Ans. Many non-chordates have impressive regeneration capabilities, allowing them to regrow lost limbs or even entire sections of their bodies.
Ques. Are Humans chordates? (3 Marks)
Ans. Yes, humans are chordates as:
- Notochord forms our backbone during development.
- Pharyngeal gill slits are present in embryos, though not used for breathing as adults.
- Our bodies have mirror-image halves on either side.
Therefore, humans belong to the phylum Chordata, along with other vertebrates like fish, amphibians, reptiles, birds, and mammals.
Ques. When were the first chordates discovered? (2 Marks)
Ans. The fossil record suggests the first chordates appeared roughly 530 million years ago, during the early Cambrian period. Fossils from China, like Yunnanozoon lividum, and the Burgess Shale in Canada, like Pikaia gracilens, provide evidence of these early chordates.
Ques. State a major difference between Chordates and Non-Chordates (2 Marks)
Ans. The presence or absence of a notochord sets apart chordates (with it) and non-chordates (without it). This flexible rod-like structure becomes the backbone in chordates, providing crucial support and playing a key role in nervous system development. Non-chordates, like insects and worms, lack this defining feature and exhibit diverse body structures and symmetries.
Ques. Are invertebrates Included in Chordates? (3 Marks)
Ans. Yes, some invertebrates are included in the phylum Chordata! Although most chordates are vertebrates (meaning they have a backbone), not all of them do. The phylum Chordata has three subphyla:
- Vertebrata subphylum includes all animals with backbones, like humans, fish, amphibians, reptiles, birds, and mammals.
- Cephalochordata subphylum includes a small group of marine invertebrates called lancelets. They have a notochord but no backbone.
- Urochordata includes another group of marine invertebrates called tunicates. They have a notochord and pharyngeal gill slits as larvae, but these disappear in adulthood.
Ques. How can chordates be classified? (3 Marks)
Ans. Chordates are classified into three main subphyla:
- The Craniata group includes all vertebrates, possessing a skull and backbone. It further branches into sub-groups like fishes, amphibians, reptiles, birds, and mammals.
- Urochordata, also known as tunicates or sea squirts, these marine animals retain the notochord only in their larval stage. Adults resemble sac-like filters feeders.
- Cephalochordata are lancelet-like creatures that have a notochord throughout their lives, but lack a skull and vertebrae. They live burrowed in sand or swim near the seabed.
Ques. What are some examples of Non-Chordate Phyla? (5 Marks)
Ans. Non-chordate phyla include diverse creatures such as –
- Cnidaria: Jellyfish, anemones, corals.
- Platyhelminthes: Flatworms, tapeworms.
- Nematoda: Roundworms.
- Annelida: Earthworms, leeches.
- Mollusca: Snails, clams, octopuses.
- Echinodermata: Starfish, sea urchins, sea cucumbers.
- Arthropoda: Insects, spiders, crustaceans.
Ques. How do chordates and non-chordates breathe? (2 marks)
Ans. Non-chordates often breathe through diffusion across their body surface, while chordates use gills or lungs depending on the species and life stage.
Ques. Do all chordates have a backbone? (2 marks)
Ans. While all chordates possess a notochord in early development, some lose it as adults. For example, lancelets (Cephalochordata) retain their notochord throughout their lives, but they lack vertebrae. Therefore, "chordate" is a broader term than "vertebrate."
Ques. How did the notochord evolve? (2 marks)
Ans. Scientists believe the notochord evolved from a dorsal rod found in ancient worm-like creatures. This rod provided structural support and helped with muscle movement. Over time, it developed into the notochord in chordates, and later into the backbone in vertebrates.
Ques. Can non-chordates be dangerous? (2 marks)
Ans. Yes, some non-chordates can be harmful. Mosquitoes, venomous insects, and parasitic worms are all examples of non-chordates that can pose health risks to humans and animals.
Ques. What's the biggest difference between chordate and non-chordate brains? (1 mark)
Ans. In general, chordates tend to have more complex brains than non-chordates. This is due to factors like the dorsal nerve cord and increased sensory information processing.
Ques. Can non-chordates regenerate limbs? (2 marks)
Ans. Many non-chordates, like starfish and flatworms, have remarkable regenerative abilities. They can regrow lost limbs, organs, and even entire sections of their bodies. This allows them to survive injuries and environmental challenges.
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