Friday, April 20, 2012

Numerical strength and size of chorodata


Numerical strength of chorodata:-
                             The number of chorodata in comparision to other phylum of invertebrate is not so large.There are about 49000 species of chorodata recorded till now  which is only half of the species of Molluscs and less than one tenth of the Arthropods.The two subphyla Cephalochorodata and Urochorodata numbers nearly 2500 species and the sub phylum vertebrata includes 46500 species.Among the vertebrata , fishes ate the most numerous with approximately 25,000 species.The number of Amphibians species is 2500, reptiles 6000, birds 9000 and mammals 4500 species .
Size of the chorodates:-
Though the number of chorodates is not so 
blue whale
high but they make disproportionate              
contribution to the biomass of the earth. 
Nearly all of them are medium to large
 in size. Some of these vertebrates are
 so large that they are the largest animals 
on the earth. The largest animal on the        
blue whale at sea shore
earth is Blue whale is 35 meters long          
and 120 tons in weight.Its scientific 
name is Balaenoptera musculus.  Even the second largest   animal on  the earth is a vertebrate. It is called the whale shark  commonly and scientifically named as
Rhineodon typus.It is 15 meter in length 
 and the smallest fish isPhilippine goby
whale shark
 scientifically known as Pandaka is only 
10mm in length.
Pandaka pygmea
Pandaka