Question

Based on the common features like presence of notochord and dorsal hollow neural system, animals like fishes, amphibians, reptiles, birds along with mammals are included in which Phylum?
A) Mammalia
B) Chordata
C) Primata
D) Insecta

Answer 1

Hint:Notochord is an embryonic rod-like structure present below the nerve cord. It is a midline tissue. Dorsal hollow neural system refers to the dorsal nerve cord. Dorsal nerve cord is a hollow tube which runs from one end of the body to another.

Complete answer:
In an animal kingdom, animals are broadly divided into 2 phylums; chordata and non-chordata. Animals with a notochord are called Chordates while those without a notochord are called Non-chordates. In Chordates the notochord is present in at least one part of their life cycle.

Chordates are further subdivided into 3 subphyla:
i) Vertebrates which include fishes, reptiles, amphibians, birds and mammals
ii) Urochordata which includes Sea Squirts, and
iii) Cephalochordata which includes Lancelets.

There are 5 features which are characteristic of Phylum Chordata and present in all chordates during some stage in their life. They are:
-A notochord
-A dorsal hollow neural system
-Thyroid Gland
-Pharyngeal Slits
-A post anal tail.

Let us analyse the options to find the correct answer
>Option A: Mammalia is a subphylum of Phylum Chordata. Hence, this is an incorrect option.
>Option B: Based on the common features like presence of notochord and dorsal hollow neural system, animals like fishes, amphibians, reptiles, birds along with mammals are included in Phylum Chordata. Hence, this is the correct option.
>Option C: Primata is an order of subphylum Mammalia. Hence, this is an incorrect option.
>Option D: Insecta is a group of invertebrates belonging to Phylum Arthropoda. Hence, this is an incorrect option.

Thus, the correct answer is option (B) Chordata.

Note:
i) A backbone or a vertebral column replaces notochord in adult chordates.
ii) Mesoderm gives rise to Notochord.
iii) Notochord is important for vertebrate development, provides signal to surrounding tissues for patterning and provides rigid support.
iv) Notochord is a skeletal rod and is a site attachment for skeletal muscles.
v) Dorsal nerve cord arises from ectoderm.
vi) Nerve cord gives rise to the central nervous system and spinal cord in chordates.
vii)It helps in control and integration in the body.