Short type Questions with Answers from Invertebrate

(11) In which animal Aristotle's Lantern found ? Mention its function.

(Ans) :- Aristotle's Lantern found in the class Ecinoidea, under the phylum Echinodermata(sea urchin).

Function :- Acts as masticating apparatus to which teeth are attached.

(12) Write the  scientific name of Portugueese-man-of war ? In which phylum does it belong ?

(Ans) :- Physalia physalis (phylum-Cnideria ; class-hydrozoa)

(13) Mention the utility of Byssus threads ?

(Ans) :- Bivalvia having strands of byssus by which the animals are often attached to the substratum or objects. A byssal gland is located in the foot sescretes a fluid protein which passes down a groove along the underside of the foot; the secretion hardens on exposure to sea water.

(14) What is Cnidoblast ?

(Ans) :- A round or oval. epidermal cell with a basal nucleus, typical of cnidaria, that contain nematocyst.

(15) What is Sclerosepta ?

(Ans) :- Each corallite consists of cup. The wall of cup enclosing the aboral position of the polyp is termed as theca. The ridges of the cup are called Skeletal septa or Sclerosepta.

(16) What is Biradial symmetry ? Cite an example of an animal having this type of symmetry.

(Ans) :- The arrangement of body components of an animal such that similar parts are located to either side of the central axis & each of the four sides of the body is identical to the oposite side but different from the adjacent side.
Found in sea walnuts (ctenophora)

(17) Name two free living Platyhelminthes ?

(Ans) :- Planaria, Convoluta, Thysanozoon, Bipalium etc.

(18) Define metamerism ? give an example.

(Ans) :- Metamerism is a serial repetition of similar body segments along the longitudinal axis of the body. Each segment is called metamere or somite. It is found in the phylum Annelida.

(19) Give an example of animals having only polypoid & only medusoid characteristics ? Mention their respective classes.

(Ans) :- Polypoid- Metridium (class- Anthozoa) ;
             Medusoid- Aurelia aurita (class- Scyphozoa)

(20) Write the function of Madriporite ?

(Ans) :- Sieve like structure that is the intake for the water vascular system of echinoderm.In echinodermata a sieve like, button shaped process on the aboral surface of the body; through its opening the water vascular system is connected to the water outside.