Difference Between Chordates and Non-chordates

Chordates and Non-chordates are primarily differentiated by the presence or absence of an important structure called the notochord at some point in their lifecycle. However, there are many more differences that separate these two groups of organisms. Read on to learn the difference between chordates and non-chordates.

Difference Between Non-chordates and Chordates

Chordates

Non-chordates

Notochord

Present (at least in one stage in their lifecycle)

Absent. Non-chordates do not have a

Cold Blooded/Warm Blooded

Chordates can either be cold-blooded or warm-blooded

All non-chordates are cold-blooded

Mode of Respiration

Respiration occurs either through lungs or gills

Non-chordates respire through tracheae, gills or body surface

Presence of Haemoglobin

Present

Absent. Hemolymph is present, which is analogous to blood in the vertebrates

Germ Layer

Chordates are triploblastic

Non-chordates can either be triploblastic, diploblastic, or neither

Symmetry

Chordates are bilaterally symmetric

Non-chordates can either be bilateral, radial, bi-radial, or asymmetrical.

Coelom

True coelomates

Can be either true coelomates, acoelomates, pseudocoelomates.

Tail (post-anal)

Usually present

Absent

Exoskeleton

Present in some animals, such as tortoises.

Present

Endoskeleton

Present

Absent

Regeneration

Mostly poor

Mostly good

Nerve Chord

Dorsal, single, without ganglia

Ventral, double, usually bears ganglia

Blood Circulation

Closed

Usually open circulation

Anus

It is differentiated and opens before the last segment

Usually absent. If present, it opens on the last segment

Brain

Present, dorsal to pharynx in head

Present in some cases, but nowhere as complex as the brain in chordates.

Organization

Organ-system

Protoplasmic to organ-system

Heart

Ventrally placed

Absent. Dorsal/ lateral placement if present

Example

Mammals

Arthropods

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Frequently Asked Questions on Chordates and Non-chordates

How are chordates different from non-chordates?

Chordates and Non-chordates are primarily differentiated by the presence or absence of an important structure called the notochord.

Are any invertebrates present in chordates?

Some invertebrates are classified as chordates as they have a notochord, though they lack a proper backbone. Invertebrates that are considered chordates are tunicates and lancelets.

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