Question

Urochordata, Hemichordata, and Cephalochordata are collectively known as
A.Acrania
B.Protochordate
C.Lower Chordata
D.All of the above

Answer 1

Hint: In the five-kingdom classification, the chordates belonging to kingdom Animalia are the organisms that possess a spinal cord or a dorsal nerve cord. The phylum is divided into many subphyla. Urochordata, Hemichordata, and Cephalochordata belongs to the subphylum under Chordata

Complete step by step answer:Urochordata or Tunicata are exclusively marine and these organisms possess a notochord and a dorsally present nerve chord along with pharyngeal slits and a post-anal tail. They are the most primitive chordate animals. Hemichordata consists of marine animals, possess a notochord and a hollow neural tube. Cephalochordata is also marine animals, which possess a notochord, nerve cord, and a post-anal tail.
All these organisms belong to the subphylum under Vertebrata. Since these animals don’t have a head, skull, or cranium they are very primitive and small chordates, hence they belong to Acrania, having a body which does not possess a distinctive head portion
They are also known as Protochordates since they do not possess a well developed spinal cord and they possess a primitive nerve chord instead, they are also known as lower Chordata.
Thus from the above-given options D is the most appropriate option. All of the above, since the organisms are collectively known as Acrania, Protochordata, or Lower Chordata.

Note:Another subphylum under Chordata is Vertebrata. These organisms possess a true spinal cord or sometimes a less advanced notochord. The spinal cord is covered by a boney and hollow vertebral column. The subphylum is further divided into various classes such as Agnatha, Chondrichthyes, Osteichthyes, Amphibia, Reptilia, Aves, and Mammalia.