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Animal Kingdom Classification
Animal Kingdom is divided into two major groups: the non chordata and Chordata, based on the presence of notochord.
Chordata and Non Chordata
In chordates a notochord is present at some period of their life. In non chordates it is absent at any stage in their life.
What is Notochord?
Notochord is a turgid and flexible rod running along the dorsal side below the nerve cord. It forms the body axis and gives support to the body.
I. Non Chordata
Non chordata, includes a number of phyla.
- Phylum Porifera
- Phylum Coelenerata
- Phylum Platyhelminthes
- Phylum Aschelminthes
- Phylum Annelida
- Phylum Arthropoda
- Phylum Mollusca
- Phylum Echinodermata
It includes primitive plant like sessile animals called sponges. Nearly 5000 species of sponges are known today. Most of them are marine and found attached to rocks. A few are fresh water forms.
- Phylum Porifera: General Characters and more
Sponges constitute the Phylum Porifera ( L. porus, pore+ ferre, to bear) which are the simplest type of metazoans. The term Porifera was coined by Robert Grant and it means “pore bearers” due to the presence of tiny pores on their body.
Phylum Cnidaria (Coelenterata)
It includes about 9,000 species. They are marine. A few are fresh water forms.
- Phylum Cnidaria (Coelenterata): General Characters and more
Coelenterates (Gr. koilos, hollow+enteron,gut).are the simplest of eumetazoans. This interesting group of animals take its name from the large cavity in the body that serves as the intestine.They include the hydra, jelly fish, sea anemones and corals
This phylum includes 13,000 species. Most of them are parasites. Some of them are free living. They are the first group of animals with bilateral symmetry. This is the first group of animals with anterior end develops to a head. The process of formation of head is called cephalization.
- Phylum Platyhelminthes : General Characters
Flat worms vary in size from microscopic fluke to the large tape worms that may become 12 metres in length. Some of them are them are free living (e.g. Planaria) in fresh, or salt waters or in moist places on land and others are parasites.
- Classes of Platyhelminthes
Phylum Platyhelminthes is divided into three classes (Trematoda,Turbellaria and Cestoda)
Phylum Aschelminthes (Nemanthelminthes)
This phylum includes roundworms. These are either living or parasitic. These are the first tubular gut with a a mouth and anus. The body cavity is derived from embryonic mesoderm it is called pseudocoelom.
Ascaris lumbricoids (Round worm)
It is the common round worm found in intestine of children. The disease caused by Ascaris is called ascariasis. It is characterized by malnutrition, anemia and intestinal obstruction.
This phylum includes the segmented worms. These animals form the first group to show the true body segmentation. About 10000 species of Annelids are identified today.
Phylum Arthropoda forms the major phylum with 9 lakhs species of organisms. In includes crabs, prawns, insects, spiders, scorpions, mites, millipedes and centipedes.
Phylum Mollusca is the second largest phylum after the the arthropoda. over 60,000 species are included in this phylum.
This phylum echinodermata includes about 6000 species. Starfishes, sea urchins, brittle star, sea cucumber, sea lily etc. are the common forms. All of them are marine.
Chordata is the most advanced animal phylum with about 65000 living species. All chordates shoe three basics characters in common i e., Notochord, Dorsal tubular nerve cord and Pharyngeal gill slits.
- Example of Chordata
Phylum Chordata with examples
- Animal Kingdom - Multiple Choice Questions and Quizzes
Multiple Choice Questions on Animal Kingdom
Phylum Chordata is divided into three subphyla.
Cephalochordata and Urochordates are often grouped to together as protochordata. Vertebrates are considered as higher chordates.
- Class Pisces
- Class Amphibia
- Class Reptilia
- Class Aves
- Class Mammalia