Summary & Tables
TABLE 4.1: Chordates vs Non-chordates
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| No. | Chordates | Non-chordates |
|---|---|---|
| 1. | Notochord present. | Notochord absent. |
| 2. | Central nervous system is dorsal, hollow and single. | Central nervous system is ventral, solid and double. |
| 3. | Pharynx perforated by gill slits. | Gill slits are absent. |
| 4. | Heart is ventral. | Heart is dorsal (if present). |
| 5. | A post-anal part (tail) is present. | Post-anal tail is absent. |
TABLE 4.2: Salient Features of Phyla
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| Phylum | Organisation | Symmetry | Coelom | Segmentation | Digestive | Circulatory | Respiratory | Distinctive Features |
|---|---|---|---|---|---|---|---|---|
| Porifera | Cellular | Various | Absent | Absent | Absent | Absent | Absent | Body with pores/canals |
| Coelenterata | Tissue | Radial | Absent | Absent | Incomplete | Absent | Absent | Cnidoblasts present |
| Ctenophora | Tissue | Radial | Absent | Absent | Incomplete | Absent | Absent | Comb plates for locomotion |
| Platyhelminthes | Organ system | Bilateral | Absent | Absent | Incomplete | Absent | Absent | Flat body, suckers |
| Aschelminthes | Organ-system | Bilateral | Pseudo | Absent | Complete | Absent | Absent | Worm-shaped, elongated |
| Annelida | Organ-system | Bilateral | Coelomate | Present | Complete | Present | Absent | Body segments like rings |
| Arthropoda | Organ-system | Bilateral | Coelomate | Present | Complete | Present | Present | Chitinous exoskeleton |
| Mollusca | Organ-system | Bilateral | Coelomate | Absent | Complete | Present | Present | Shell usually present |
| Echinodermata | Organ-system | Radial | Coelomate | Absent | Complete | Present | Present | Water vascular system |
| Hemichordata | Organ-system | Bilateral | Coelomate | Absent | Complete | Present | Present | Proboscis, collar, trunk |
| Chordata | Organ-system | Bilateral | Coelomate | Present | Complete | Present | Present | Notochord, Gill slits |
Chapter Summary
The basic fundamental features such as level of organisation, symmetry, cell organisation, coelom, segmentation, and notochord have enabled us to broadly classify the animal kingdom.
Vertebrate Note: All vertebrates are chordates, but all chordates are not vertebrates. This is because the embryonic notochord is replaced by a vertebral column in adult vertebrates.