Identifying features of arthropoda of tge …

Characteristics of phylum Arthropoda:

(i) Triploblastic, bilaterally symmetrical and metamerically segmented animals.

(ii) Body segments are grouped into two regions - cephalothorax (head and thorax together) and abdomen, or three regions - head, thorax and abdomen. Anterior part of body forms a distinct head, bearing sense organs and brain.

(iii) Exoskeleton of cuticle, containing protein, lipid, chitin and often calcium carbonate is secreted by underlying epidermis and shed (moulted) at intervals.

(iv) Alimentary canal is complete; mouth and **** lie at opposite ends of the body.

(v) Respiration through general body surface, by gills, air tubes (tracheae) or book-lungs.

(vi) True nephridia is absent. Excretion is by coelomoducts, malphigian tubules or green or coxall glands.

(vii) Sexes are usually separate; sexual dimorphism is well marked in several forms.

(viii) Fertilisation is usually internal, oviparous or ovoviviparous and often with metamorphosis.