Tag: cnidaria

Questions Related to cnidaria

Ctenophora shows affinities with 

zoology animal diversity - i (inverterbrate phyla) ctenophora phylum ctenophora cnidaria

  1. Cnidaria

  2. Aschelminthes

  3. Cephalopoda

  4. Turbellaria

Show answer
Correct Option: A
Explanation:

Ctenophora shows several affinities with Cnidaria, some of them are:

1. The radial and tetramerous symmetry of the body, like the medusa of the hydrozoans.
2. Arrangement of parts along oral-aboral axis. 
3. Presence of branching gastrovascular canals and absence of coelom.
4. Presence of tentacles and statocyst.
5. Endodermal nature of gonads etc.
Hence, option A is correct.

Which of the following phylum includes comb jelly?

zoology animal diversity - i (inverterbrate phyla) ctenophora phylum ctenophora cnidaria

  1. Mollusca

  2. Echinodermata

  3. Coelenterata

  4. Ctenophora

Show answer
Correct Option: D
Explanation:

Ctenophores, commonly known as sea walnuts or comb jellies are exclusively marine, radially symmetrical, diploblastic organisms with tissue level of organization. The germs layers include ectoderm and endoderm. 

So, the correct answer is option D.

Hydra recognizes its prey by

zoology animal diversity - i (inverterbrate phyla) ctenophora phylum ctenophora cnidaria

  1. Nematocyst

  2. Smell

  3. Sensitivity

  4. None of the above

Show answer
Correct Option: A
Explanation:

Hydra traps its prey by  tentacles which are present at the opening of the gastrovascular cavity. Scattered over the outer layer tentacles are a great many of these stinging cells called cnidoblasts. Each cnidoblast contains a capsule (nematocyst) from which projects a small trigger called a cnidocil. Inside each capsule is a tiny hollow thread. It is inverted like a finger of a glove which is pushed into the hand part. These threads are the food-catching apparatus. 

So, the correct answer is option A.

 A. Symmetry of ctenophorans  1. Haeckelia
 B. Ctenophora with nematocyst  2. Radial
 C. Habitat of comb jellies   3. Colloblast
 D. Specialised cells of comb jellies  4. Marine


zoology animal diversity - i (inverterbrate phyla) ctenophora phylum ctenophora cnidaria

  1. A- 3, B- 4, C- 2, D- 1

  2. A- 4, B- 3, C- 2, D- 1

  3. A- 1, B- 2, C- 3, D- 4

  4. A- 2, B- 1, C- 4, D- 3

Show answer
Correct Option: D
Explanation:
The ctenophores have radial symmetry. They have elongated and tubular body. They are attached to the substratum by on end. The other end has an opening called as mouth which is surrounded by long tentacles. Thus, the symmetry of these organism are called as biradial symmetry. 
Species of Haeckelia are known to carry nematocysts on their medusae. They carry the nematocysts on their tentacles. There are nematocysts which are arranged on the medusae. 
Habitat of comb jellies is marine waters. They can survive in shallow waters as well as in depth. Some of the species are found near the water surface.
Specialised cells are present in comb jellies which are known as colloblasts. These are sticky type of cells and adhere to the prey. This helps in capturing the prey as these organisms lack the stinging cells. 
Thus, the correct answer is option D. 

The symmetry exhibited by comb jellies is

zoology animal diversity - i (inverterbrate phyla) ctenophora phylum ctenophora cnidaria

  1. Spherical Symmetry

  2. Bilateral symmetry

  3. Biradial symmetry

  4. None of the above

Show answer
Correct Option: C
Explanation:

Ctenophore phylum which includes Comb jellies exhibit Biradial symmetry. It is when the organism can be divided up into equal parts, but with two planes only. Hence option C is correct.

Comb jellies are 

zoology animal diversity - i (inverterbrate phyla) ctenophora phylum ctenophora cnidaria

  1. Strong swimmers

  2. Phytoplanktons

  3. Planktonic animals

  4. None of the above

Show answer
Correct Option: C
Explanation:

Comb jellies are not strong swimmers. They are typically planktonic animals, transparent and unpigmented and most swim by the synchronous beating of the eight rows of comb plates. Hence, option C is correct.

Why does the Ctenophora is a minor phylum?

zoology animal diversity - i (inverterbrate phyla) ctenophora phylum ctenophora cnidaria

  1. It includes small sized animals.

  2. It includes only few genera.

  3. It does not includes animals of economic importance.

  4. It was included earlier in Cnidaria.

Show answer
Correct Option: B
Explanation:

Ctenophora is considered as a small phylum. The phylum contains very few genera and only about 80 species. This group includes a set of marine animals. These organisms are commonly called as comb jellies. Earlier, this phylum was placed under Coelenterata. Hatschek placed it under a separate phylum. 

Thus, the correct answer is option B. 

Biradial symmetry and lack of cnidoblasts are the characteristic of 

zoology animal diversity - i (inverterbrate phyla) ctenophora phylum ctenophora cnidaria

  1. Hydra and starfish

  2. Starfish and sea anemone

  3. Ctenoplana and Beroe

  4. Aurelia and Paramoecium

Show answer
Correct Option: C
Explanation:

Biradial symmetry and lack of cnidoblasts are characteristics of phylum Ctenophora. They have adhesive structure, known as coloblasts instead of cnidoblasts. Both Ctenoplana and Beroe are ctenophores. Hence, option C is correct.

Ctenophores have the following symmetry

zoology animal diversity - i (inverterbrate phyla) ctenophora phylum ctenophora cnidaria

  1. Spherical

  2. Pentaradial

  3. Biradial

  4. All of the above

Show answer
Correct Option: C
Explanation:

The ctenophores are diploblastic with a biradial symmetry or modified radial  (with an underlying bilateral symmetry), which is a bit different than the radial symmetry typical of cnidarian.

A radially symmetrical free swimming bioluminescent diploblastic marine organism is

zoology animal diversity - i (inverterbrate phyla) ctenophora phylum ctenophora cnidaria

  1. Sea Fan

  2. Sea Pen

  3. Sea Walnut

  4. Bath sponge

Show answer
Correct Option: C