Tejinder Kaur, Academic Content Writer at Edumarz
The word annelida is derived from Greek work “annulus” meaning ring because there body is divided into segments.
They display characteristic metameric segments i.e. their body is divided into continuous serial segments.
Habitat is marine, freshwater as well as terrestrial.
The body is well differentiated into head and tail.
The body is bilaterally symmetrical.
Have a triple layer of cells hence called triploblastic.
Example: Earthworm , leech
The word arthropoda means jointed legs i.e. the organisms of this phylum have jointed limbs.
This is the largest phylum of the animal kingdom i.e. displays the largest diversity.
The animals of this phylum have characteristic jointed appendages, hard exoskeleton and a segmented body.
They have well developed organs and organ systems.
The circulatory system is open i.e. blood flows directly in the body cavity, no proper blood vessels present.
Example: Spiders, butterflies
The animals of this kingdom have a soft body.
The body is divided into head, trunk and foot.
The body is triploblastic and bilaterally symmetrical.
The organ and organ system is well developed.
The circulatory system is open.
No limbs seen.
Example: Snail, Octopus
The word Echinodermata is made up of the Greek word “echinos” meaning spines i.e. the animals of this phylum have bodies covered by spines.
The habitat is marine.
The animals have a well developed characteristic “water vascular system” which helps in major metabolic activities.
Have well developed coelom hence called Coelomates.
Have a skeleton made up of Calcium Carbonate.
The symmetry is radial i.e. the body can be divided into two halves by more than one plane passing through the centre.
Example: Starfish, Star Urchins
The body is divided into head, trunk and proboscis.
Animals of this phylum have single layered epidermis.
Well developed organ system is present.
Have an open circulatory system.
Gills are developed for respiration.
The fertilization is external i.e. the germ cells are released externally for fusion.
No larval stage is a stage so the development is direct.
Well developed characteristic notochord is present.
The animals have bilateral symmetry, are triploblastic and have organ system level of classification.
The circulatory system is closed i.e. blood flows in blood vessels.
The phylum is subdivided into three subphyla: