10. Given below are fate map of two organisms and the pattern by which embryos undergo cleavage. Which of the following is/are the right combination(s)?
(1) B only (2) B and A
(3) A and C (4) B and D
The correct answer depends on matching fate maps and cleavage patterns that fit the distinct developmental biology observed in different species.
Comparative studies show that cleavage patterns and fate maps are generally conserved within major taxa, even though there can be evolutionary modifications in cleavage types without drastic changes in fate maps. Amphibians, for instance, typically present fate maps consistent with holoblastic radial cleavage, whereas mammals demonstrate fate maps aligning with holoblastic rotational cleavage. Birds and reptiles, with telolecithal eggs, show discoidal cleavage with fate maps reflecting partial division above the yolk, and insects exhibit superficial cleavage and fate maps correlating with cellularization in the peripheral cytoplasm.
Out of the provided combinations, the option(s) consistent with established fate map and cleavage pattern relationships are most likely:
(1) B only
or, if more context like specific organisms are given:
(2) B and A
Introduction
Embryonic development begins with cleavage and the establishment of cell fate maps that define where future tissues originate. The relationship between how embryos split their cells (cleavage patterns) and how these cells are destined to become organs (fate maps) is key to understanding developmental biology and evolution.
Cleavage Patterns and Fate Maps: The Link
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Cleavage patterns distribute yolk content and cytoplasm, influencing cell potency and eventual fate.
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Fate maps constructed for species like amphibians (radial cleavage), mammals (rotational cleavage), birds (discoidal cleavage), and insects (superficial cleavage) show that early cleavage divisions set the framework for organ and tissue formation.
Choosing the Correct Combination
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Historical and experimental studies emphasize that fate maps remain broadly conserved, even if cleavage patterns evolve or diversify.
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The combinations where fate maps and cleavage patterns correspond as expected (e.g., mammals with rotational cleavage, amphibians with radial cleavage) are correct.
Conclusion
The biological accuracy of fate map and cleavage pattern combinations has been confirmed by decades of embryological research. Matching these features correctly aids our understanding of animal development and comparative embryology.
Final Answer:
(1) B only (or (2) B and A, depending on the precise organism context)
