What is the difference between Mollusca and Protochordata.
Dear student.
Phylum Mollusca
It is the second largest phylum after arthropods. Its members are commonly called soft-bodied animals.
General features of molluscs
Though mostly present in seas, they may be found in freshwater or on land as well.
The body of a mollusc is not segmented like those of an annelid and an arthropod.
They have an organ system level of organization.
They show bilateral symmetry.
A mollusc has an open circulatory system and possesses kidney-like organs for excretion.
Molluscs are triploblastic animals.
The coelomic cavity (schizocoelom) is reduced and there is little segmentation.
The body is divided into an anterior head, a ventral muscular foot and a dorsal visceral mass.
The soft body is covered by a hard shell.
A mollusc has a distinct foot for moving around.
Examples of molluscs: Octopus, Pila (freshwater snail), Unio (freshwater mussel), Sepia (cuttlefish), Loligo (squid)
Phylum Mollusca
It is the second largest phylum after arthropods. Its members are commonly called soft-bodied animals.
General features of molluscs
Though mostly present in seas, they may be found in freshwater or on land as well.
The body of a mollusc is not segmented like those of an annelid and an arthropod.
They have an organ system level of organization.
They show bilateral symmetry.
A mollusc has an open circulatory system and possesses kidney-like organs for excretion.
Molluscs are triploblastic animals.
The coelomic cavity (schizocoelom) is reduced and there is little segmentation.
The body is divided into an anterior head, a ventral muscular foot and a dorsal visceral mass.
The soft body is covered by a hard shell.
A mollusc has a distinct foot for moving around.
Examples of molluscs: Octopus, Pila (freshwater snail), Unio (freshwater mussel), Sepia (cuttlefish), Loligo (squid)
Protochordata means the first chordates or the animals which first showed the presence of notochord. The group includes cephalochordates, hemichordates and tunicates. They have nerve cords but the backbone is absent. Organisms like Lamprey, sea squirts etc are protochordates.
It is divided into two groups:
Urochordata: Animals whose free swimming larvae show notochord while adults do not.
Cephalochordates: Fish like animals with notochord that remains throughout their lives.
Regards.