Question

Gastrulation in frog is completed by:
1. By epiboly
2. By emboly
3. Both a) and b)
4. By delamination

Answer 1

Correct Answer - Option 3 : Both a) and b)

Concept:

• Gastrulation is the stage of embryonic development in which Blastula (single-layered) is differentiated into multiple layered gastrulae.
• In gastrulation, the rate of cleavage division slows down and ultimately stops at the end of gastrula formation.
• It is the most important stage in embryonic development because two main events take place during this stage.

1. DIfferentiation of blastomere into the three germinal layers - The Ectoderm, Endoderm, and Mesoderm.
2. Morphogenetic movements: During this stage, the blastomeres perform amoeboid movement and reach their definite place in the embryo.

 

Explanation:

• There are two basic methods of gastrulation:

1. Epiboly: Movement of the blastomere that forms the Ectoderm
2. Emboly: Movement of the blastomere that forms the Mesoderm and Endoderm.

• In frogs, gastrulation is performed by both epiboly and emboly.

​

• Embryo consumes maximum oxygen during the gastrula stage because of the respiratory activity of the embryo increases.

• Delamination is one of the methods by which the various blasto dermic layers of the ovum are differentiated.