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Difficulty: MediumVertebrates: Homoiothermic Classes (Aves and Mammalia)

In homoiothermic vertebrates, mature red blood cells (erythrocytes) of birds (Aves) lack a cell nucleus at maturity to maximize space for oxygen transport, whereas mature mammalian erythrocytes retain a prominent nucleus.

Answer: Answer

Answer

The statement is false. Mature mammalian erythrocytes are anucleated (lack a nucleus) to maximize hemoglobin capacity, whereas mature erythrocytes in birds (Aves) retain their nuclei.
Mature mammalian erythrocytes lose their nuclei (anucleated) to optimize oxygen transport capacity, while mature avian erythrocytes remain nucleated. Therefore, claiming that birds lack a nucleus while mammals retain one is factually incorrect.

Step-by-Step Solution

1
Examine the cellular structure of mature mammalian red blood cells.
During erythropoiesis in mammals, mature erythrocytes expel their nuclei (enucleation) to maximize intracellular space for hemoglobin.
Anucleation allows mammalian RBCs to carry more oxygen efficiently and assume a flexible biconcave disk shape.
2
Examine the cellular structure of mature avian red blood cells.
Avian erythrocytes do not undergo enucleation and remain oval, biconvex cells containing a visible nucleus at maturity.
Class Aves retains nucleated red blood cells despite having high metabolic demands characteristic of homoiothermic animals.
3
Compare the structural traits against the given statement.
The statement incorrectly reverses the nuclear characteristics of mature avian and mammalian erythrocytes.
Because mammals possess anucleated mature RBCs and birds possess nucleated mature RBCs, the assertion is false.

Key Concept

Structural differences in mature erythrocytes between Class Aves and Class Mammalia
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Topics

Vertebrates: Homoiothermic Classes (Aves and Mammalia)

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