Chordata is the last phylum of kingdom Animalia.
Which is further subdivided into subphylums, divisions and classes.
The Slides shows the classification of the phylum along with the basis on which it is classified.
(includes examples along with pictures for easy understanding and memorizing)
4. Diversity of chordata
● 64832 species on record
● 32120 fishes
● 6771 amphibians
● 9320 reptiles
● 9026 birds
● 5750 Mammals
● smallest - 10mm
[philippine gody]
● largest - 35 m Blue
Whale]
5. GENERAL CHARACTERISTICS
● Aquatic, terrestrial or aerial.
● All free living. no parasitic
● bilaterally symmetrical
● Presence of post anal tail
● Exoskeleton
● Triploblastic
● True coelom
● Cartilaginous or bony endoskeleton
6. ● Pharyngeal gill slits at some stage, may/may not be
functional]
● Complete digestive system
● Closed blood vascular system
● Excretory system - proto/meso/metanephric kidneys
● Dorsal and tubular nerve cord
● Disexual
9. Notochord
● Notochord is elongated
● Rod like
● Flexible
● Present beneath nerve cord
● Prime feature of chordates
10. Pharyngeal gill slits
● At some stage
● Paired lateral gill slits
● Pharyngeal wall of gut behind mouth
● Protochordates - present throughout life
● Higher vertebrates - disappear / modifies in adult
11.
12. CLASSIFICATION
On the basis of -
● Presence of notochord or vertebral column
● Presence or absence of Cranium
13.
14. GROUP A: Acrania (protochordata)
➔ All marine
➔ Primitive
➔ Lacks head/skull/cranium
➔ Divided into three subphylum
◆ Hemichordata
◆ Urochordata
◆ Cephalochordata
15. Subphylum I. Hemichordata
➔ Body division : Proboscis, collar and trunk
➔ Notochord short; confined to proboscis
➔ Have 4 classes
16. Class I: Enteropneusta
➔ Worm like body
➔ Numerous gill slits
➔ Straight intestine
➔ Also known as tongue worms
Balanoglossus
18. Class II: Planctosphaeroidea
➔ Round and transparent
➔ Branched ciliary bands
➔ L shaped alimentary canal
Class IV: Graptolita
➔ Were present in abundant in Ordovician and silurian
period
➔ The extinct class of Hemichordata tubular chitinous
Dendrograptus
[graptolita]
19. Subphylum II. Urochordata / Tunicata
➔ Notochord in larval stage only
➔ Adult sac like
➔ Sessile
➔ Encased in protective tunic
➔ Divided into 3 classes
◆ Ascidiacea
◆ Thaliacea
◆ Larvacea/Appendicularia
22. Subphylum III. Cephalochordata
➔ Notochord and nerve cord present
throughout life along entire length body
➔ Class Leptocardii
◆ Body fish like
◆ Segmented with distinct myotomes
and numerous gill-slits
◆ Have one family, 2 genera and 30
species
Asymmetro
n
23. Group B: Craniata / Euchordata
➔ Aquatic terrestrial
➔ With distinct head
➔ Vertebral column
➔ Jaws
➔ Brain protected by skull or cranium
24. Subphylum IV. Vertebrata
➔ Notochord replaced by vertebral column
➔ Body divisible into head,neck, trunk and tail
➔ Largest subphylum with 46500 species
➔ Two Divisions
◆ Agnatha
◆ Gnathostomata
25. DIVISION I: Agnatha
➔ Jawless primitive fish
➔ Without true jaws
➔ Paired limbs
➔ Have 3 classes
➔ Class I: Ostracodermi
◆ The extinct order
◆ Primitive heavily armoured
◆ The first vertebrate
Cephalap
sis
26. ➔ Class II: Cyclostomata
◆ Eel shaped
◆ Without scales, jaws and lateral fins
◆ Mouth round and suctorial
Myxine
