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Category Archives for "Animal Taxonomy"

Phylum Chordata: Characteristics and Its Classification

The chordates were originated from a fish-like ancestor, very similar to the larva of the Ascidia (Tunicata) and it is assumed that they became the ancestor of the chordates by retaining the larval form throughout the life. In the palaeozoic age, the chordates were originated from some sessile Echinoderms, which were bottom dwellers of the […]

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Phylum Platyhelminthes : General Characteristics and Its Classification

The representatives of the phylum Platyhelminthes are commonly known as the flatworms or tapeworms. The word ‘Platyhelminthes’ is derived from the Greek word, ‘platy’ meaning flat and ‘helminth’ meaning worm. They are simple soft-bodied, bilaterian, unsegmented invertebrate animals. The Phylum Platyhelminthes makes up the 4th largest phylum among the animal kingdom. But among the acoelomate […]

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Phylum Arthropoda: General Characteristics and Its Classification

Phylum Arthropoda is the largest animal group which constitutes the largest percentage of the world’s organisms. It is estimated that about 84% of all known species of animals belong to this phylum and number of known species vary between 1,170,000 and 5 to 10 million. Besides these, many arthropods are not yet unidentified. Some prominent […]

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Phylum Echinodermata: General Characteristics and Its Classification

The term ‘Echinodermata’ is derived from Greek words ‘echinos’ meaning ‘spiny’ and ‘dermos’ meaning ‘skin’. The representatives of phylum Echinodermata are absolutely marine organisms and this phylum contains about 7,000 known living species. Among them, notable species are sea urchins, brittle stars, sand dollars, sea cucumbers, sea stars, etc. Scientists did not trace any freshwater […]

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Phylum Mollusca: General Characteristics and Its Classification

Mollusca makes the second largest phylum of non-chordate animals including snails, octopuses, sea slugs, squid, and bivalves such as clams, oysters, and mussels.  This phylum contains about 100,000 described species. Among all known marine species, 23% are mollusks. But some species live in freshwater and terrestrial habitats. This group displays a broad range of morphological […]

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Phylum Annelida: General Characteristics and Its Classification

The representatives of the phylum Annelida are known as segmented worms or ringed worms. Annelida is derived from Latin word ‘anellus’ meaning little ring. It is a large phylum with over 22,000 living species. Among them,  Polychaetes constitute about 12,000 species while Clitellates contains about 10,000 species. The major groups include earthworms, ragworms and leeches. […]

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Porifera : Characteristics and Classification

Scottish Anatomist and Zoologist Robert Edmond Grant proposed the name Porifera (L. Porus, pore and ferre, to bear). The representatives of Phylum Porifera are also known as Sponges. They are simple types of aquatic invertebrates. This phylum contains about 10000 species; among them, most of the species are Marine and some are freshwater (about 100 species). […]

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