Write a short note on Phylum Arthropoda.

(N/A) $\rightarrow$ Arthropoda is the largest phylum of Kingdom Animalia,which includes insects.
$\rightarrow$ Over two-thirds of all named species on earth are arthropods.
$\rightarrow$ They exhibit an organ-system level of body organization.
$\rightarrow$ They are bilaterally symmetrical,triploblastic,segmented,and coelomate animals.
$\rightarrow$ The body of arthropods is covered by a chitinous exoskeleton.
$\rightarrow$ The body consists of a head,thorax,and abdomen.
$\rightarrow$ They possess jointed appendages (arthros = joint,poda = appendages).
$\rightarrow$ Respiratory organs include gills,book gills,book lungs,or a tracheal system.
$\rightarrow$ The circulatory system is of the open type.
$\rightarrow$ Sensory organs like antennae,eyes (compound and simple),and statocysts (balance organs) are present.
$\rightarrow$ Excretion takes place through Malpighian tubules.
$\rightarrow$ They are mostly dioecious.
$\rightarrow$ Fertilization is usually internal.
$\rightarrow$ They are mostly oviparous.
$\rightarrow$ Development may be direct or indirect.
$\rightarrow$ Examples of economically important insects:
$\rightarrow$ $Apis$ (Honey bee)
$\rightarrow$ $Bombyx$ (Silkworm)
$\rightarrow$ $Laccifer$ (Lac insect)