Most important distinguishing features of arthropoda phylum are given below:
Phylum Arthropoda literally means the animals bearing jointed feet (Gr; arthron, jointed + podos, foot).
ADVERTISEMENTS:
These are extremely successful animals and the largest no. of species about 9 lacs are known to this group.
They are defined as “bilateral and prostomial eucoelomate eumetazoa with metamerically segmented body and each segment bears a pair of jointed locomotory appendages.
Image Source: classconnection.s3.amazonaws.com
Distinguishing features :
1. They are versatile in their habitat viz; land, air, and all kinds of water and free living or parasite, each kind of mode of life they show.
ADVERTISEMENTS:
2. Organ system level of body organization.
3. Body bilaterally symmetrical, triploblastic and metamerically segmented.
4. Each segment basically bears a pair of lateral jointed appendages adapted for food ingestion, locomotion, respiration, copulation etc.
5. Exoskeleteton of dead chitinous cuticle which sheds at intervals, the process called ecdysis or moulting for growth and development.
ADVERTISEMENTS:
6. Body is divisible into head, thorax and abdomen. Head and thorax are often fused to form a cephalothorax.
7. True coelom is reduced, only seen in excretory and reproductive organs. It is replaced by blood filled haemocoel.
8. Digestive system is complete. Mouth parts adapted for various modes of feeding habits.
9. Open blood vascular system with sinus.
10. Respiration by gills (aquatic form) or tracheae or book lungs (terrestrial forms) or by diffusion through body surface in some.
11. Excretion by coelomoducts or specialized green or coxal glands or by malpighian tubules.
12. Nervous system typically annelidan, with a dorsal brain connected with a nerve ring to a double ventral nerve cord.
13. Sensory organs comprise of eyes (simple and compound), chemo and tactile receptors and statocyst and auditory organs etc.
14. Mostly dioecious with sexual dimorphism, fertilization internal; Usually oviparous or ovoviviparous.
15. Development direct or indirect with one or many larval stages.
16. Parental care is often well marked.