Alternation of Generations in Cnidarians

Q.

What is metagenesis with example?

Q.

What is metagenesis? Mention an example which exhibits this phenomenon.

Q. Metagenesis refers to:

1. Presence of a segmented body and parthenogenesis as a mode of reproduction
2. Occurrence of a drastic change in form during post-embryonic development
3. Presence of different morphic forms
4. Alternation of generation between asexual and sexual phases of an organism

Q.

What is coelenterate metagenesis?

Q. Alternation of generations is seen in

1. Aurelia
2. Adamsia
3. Hydra
4. Obelia

Q. Assertion [A]: Obelia exhibits metagenesis.
Reason [R]: Obelia exists in both polyp and medusa form.

1. Both Assertion and Reason are true and Reason is the correct explanation of Assertion
2. Both Assertion and Reason are true but Reason is not the correct explanation of Assertion
3. Assertion is true but Reason is false
4. Both Assertion and Reason are false

Q. Which of the following traits is not common for sea anemone and jellyfish?

1. A medusa as the dominant stage in the life cycle
2. Possession of a gastro vascular cavity
3. Sexual reproduction
4. Nematocysts present on the tentacles

Q.

Is sea anemone a polyp or medusa?

Q. Consider the following statements during the alternation of generation or metagenesis in dimorphic cnidarians, the polyps are:
(1) Sedentary
(2) Free living
(3) Polyp forms the medusa sexually
(4) Polyp forms the medusa asexually
Which of the following given statements are correct?

1. 1, 3 and 4 are correct
2. 1, 2 and 3 are correct
3. 1 and 4 are correct
4. 2, 3 and 4 are correct

Q. Medusa of Coelenterata is

1. sexually reproducing
2. free swimming
3. umbrella shaped
4. all of these

Q.

Jelly fish comes under the phylum

Q. Read the following statements:

a. Polyp is sessile and cylindrical form like Adamsia.
b. Medusa is umbrella-shaped and free-living like Aurelia.
c. Polyp produce medusae sexually and medusae form the polyp asexually (e.g.: Obelia).
d. Metagenesis is seen in jellyfish.

Find out the incorrect statements.

Q.

What animal have medusa?

Q. Identify incorrect statements with regard to coelenterata.

1. Hydra is fresh water polyp
2. Aurelia contains medusa stage
3. Animals contain gastrovascular cavity
4. Gorgonia exhibits two basic forms called polyp and medusa

Q. Which of the following members of phylum Coelenterata lack a sexual medusa stage?

1. Jellyfish
2. Hydra
3. Sea ginger
4. Sea raft

Q. Which of the following terms describe the life cycle of Obelia?

1. Metamerism
2. Metagenesis
3. Regeneration
4. None of these

Q.

Metagenesis refers to

1. Metaphysic

2. Metamorphosis

3. Metagenesis

4. Metamerism

Q. For life cycle of Obelia, most appropriate term used is

1. Alternation of generation
2. Metamerism
3. Metagenesis
4. Both b and c

Q.

Hydra belongs to coelenterates.What are its special feature?

Q. Choose the odd one out from the options given below.

1. Labeo
2. Hippocampus
3. Anabas
4. Scoliodon

Q. Medusa of Coelenterata is

1. sexually reproducing
2. free swimming
3. umbrella shaped
4. all of these

Q. Find out the incorrect statement(s).

I. Polyp is sessile and cylindrical like Adamsia

II. Medusa is umbrella shaped and free-swimming like Aurelia

III. Polyps produce medusae sexually and medusae form the polyps asexually

IV. Medusae produce polyps sexually

1. I and IV
2. Only I
   
3. II and III
4. Only III

Q. Which of the following jawless fish lays eggs in fresh water and its ammocoetes larvae after metamorphosis return to the ocean?

1. Petromyzon
2. Eptatretus
3. Myxine
4. Neomyxine

Q. Which of the following members of phylum Coelenterata lack a sexual medusa stage?

1. Jellyfish
2. Hydra
3. Sea ginger
4. Sea raft

Q. The clitellum or cingulum in earthworm is present in

1. 12, 13 and 14 segments
2. 13, 14 and 15 segments
3. 14, 15 and 16 segments
4. 16, 17 and 18 segments

Q. Which of the following reproductive structures are most commonly present in algae?

1. Zoospores
2. Conidia
3. Buds
4. Gemmules

Q. Give the Zoological name of Sea- Pen?

Q. Select the option that correaly identifies A, B and C in the given figure of female thallus of Marchantia

1. A - Antheridiophore, B - Gemma cup, C - Rhizoids
2. A - Antheridiophore, B - Rhizoids, C - Gemma cup
3. A - Archegoniophore, B - Gemma cup, C - Rhizoids
4. A - Archegoniophore! B - Rhizoids, C - Gemma cup

Q. Which of the following reproductive structures are most commonly present in algae?

1. Zoospores
2. Conidia
3. Buds
4. Gemmules

Q. Which of the following animals is without sexual medusae?

1. Halistemma
2. Hydra
3. Millepora
4. Velella