~Proto chordates information ~
• Example of Proto chordates.
• According to systematics, animal kingdom is classified into many major phyla.
• O of these, phylum chordata is largest and last phylum.
• Balfour (1880 A.D.) had coined the term "chordata'.
• All animals having notochord are classified under phylum chordata. It also includes some invertebrate animals.
• Hence, animals based on the presence of notochord be can distinguished between chordates and nonchordates.
• Animals having vertebral column are known as vertebrates. While other nonchordates and some chordates are known as invertebrates.
• Hence, all vertebrates are chordates but all chordates are not vertebrates.
• Fhylum chordata is a highest, and largest phylum.
• Proto chordates includes many living and extinct animals along with human. Examples like fishes, frogs, isnakes, lizards, tiger, lion etc.
• Proto chordates In phylum chordata, about 49,000 living species are included. Out of these most of the species are vertebrates (46,600 species).
• Mohaving medium to large size.
• Proto chordates largest animal is Blue whale (Balaenoptera musculus) with length = 35 meters and weight = 1,20,000 kg (120 tonnes).
• Proto chordates :
• Notochord is elongated, rod like, flexible structure which extends to whole length of the body.
• Notochord is found between nerve cord and digestive tract.
• Notochord is originated from endoderm.
• In the structure of notochord, it is composed of large vacuolated notochordal cells containing a matrix and surrounding by an outer fibrous and an inner elastic sheath. gelatinous
~Importance of notochord ~
• It is an important characteristics of chordates, hence, it structural form is helpful in classification.
• Proto chordates During embryonic stages, it acts skeleton as supportive structure.
• Proto chordates adult vertebrates it is surrounded or replaced by vertebral column.
Proto chordates .
Proto chordates
Proto chordates
Proto chordates
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Proto chordates.