Why is cleavae in bird meroblastic and discoidal?
Answers
Explanation:
as birds has megalecicithal eggs, the yolk provides resistance to cleavage, hence the cleavage is meroblastic & discoidal. meroblastic cleavage occurs in insects & reptiles also but it is not discoidal , it is suferficial ( having centrolecithal eggs).Apr
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Answer:
Why is bird cleavage Discoidal?
The cleavage in the chick is called discoidal because it is limited to the blastodisc. EXPLANATION: Post-fertilization changes in the chicken egg are caused by several mitotic divisions. The entire egg at a point of development is divided into two poles, the vegetal pole and the animal pole.
What is the role of yolk in determining Holoblastic and Meroblastic cleavage?
The deutoplasm has no part in mitosis except it mechanically influences the activities of the protoplasm of the cell. ... The amount and distribution of the yolk will therefore determine the type of segmentation. The cleavage can be holoblastic (total or entire cleavage) or meroblastic (partial cleavage).
What is the difference between Holoblastic and Meroblastic cleavage?
The main difference between holoblastic and meroblastic cleavage is that the holoblastic cleavage occurs in the absence of a large concentration of yolk in the fertilized egg cell whereas meroblastic cleavage occurs in the presence of a large concentration of yolk.
What animals show Meroblastic cleavage?
We see meroblastic bilateral cleavage in animals called cephalopod molluscs, which are animals like octopi, squid, and cuttlefish. The second meroblastic pattern for telolecithal cells is discoidal cleavage, which is when cleavage creates a disc of cells called a blastodisc.