Advertisements
Advertisements
प्रश्न
Write short note on protochordates.
Advertisements
उत्तर
Protochordates belong to phylum Chordata. They are further subdivided into two subphylums:
(i) Urochordata
They are bag-like, sessile, soft-bodied, non-metameric animals. In these organisms, the notochord is present only in the tail of free-living tadpole-like larva. The dorsal tubular nerve chord also degenerates in the form of small ganglion in the adult. The only chordate character present in the adult form are the numerous gill slits. Urochordates are hermaphrodites. Example: Herdmania.
(ii) Cephalochordata
They are fish-like, metamerically segmented, headless and coelomate animals. In these organisms, notochord and nerve cord extend throughout the length of the body. The notochord, nerve chord and pharyngeal gill slits are retained throughout life. Sexes are separate in Cephalochordates. Example: Amphioxus.
APPEARS IN
संबंधित प्रश्न
How do annelid animals differ from arthropods?
Write down four main characters of Platyhelminthes. Give two examples.
Define the term hermaphrodite. Give two examples.
What do you mean by the term coelomate animals? Give two examples.
Give four general characters of phylum Mollusca. Write down two examples.
Write down four general characters of Porifera. Give two examples.
Write down four general characters of cnidarians (coelenterates). Give two examples.
Describe general characteristics of phylum Annelida. Give one example each class of Annelida.
Explain the general charaters of phylum Mollusca. Give one example of following classes of Mollusca;
(i) Gastropoda;
(ii) Pelecypoda;
(iii) Cephalopoda.
Name major phyla of Animal kingdom. Write down one character and one example of each of them.
What are the group names of the following categories of animals?
Animals with three pairs of legs ___________
Given below is an animal followed by three terms or features. Underline the term which does not match with the animal.
Earthworm - Invertebrata, Annelida, Insecta
Given below is an animal followed by three terms or features. Underline the term which does not match with the animal.
Grasshopper-Wings, trachea, proboscis
Name any two animals which possess compound eyes.
Give two examples of each of the following: Pisces
Give two examples of each of the following: Nemathelminthes
Fill in the blanks:
The excretory organs of platyhelminthes are ______.
What is binomial nomenclature?
Give scientific reasons.
Body temperature is not constant in amphibians.
Assertion (A): All vertebrates are chordates but all chordates are not vertebrate.
Reason (R): The members of subphylum vertebrata possess notochord, during the embryonic period, the notochord is replaced by a cartilaginous or bony vertebral column in adults.
In the light of the above statements, choose the correct answer from the options given below:
