Concept explainers
To explain: The way hypophysectomy on an early tadpole will affect the level of thyroxine hormone and metamorphosis.
Introduction: Hormones are chemicals messengers that are produced and circulated in the blood to regulate behavior, physiological, and

Explanation of Solution
A metamorphosis is an important event of tadpole life. Metamorphosis refers to the transformation of an immature form of a tadpole to its adult form. Hypophysectomy in early tadpole will disturb the entire signaling axis, thyroxine would not be secreted and metamorphosis would be blocked.
To explain: The way hypophysectomy on a late tadpole will affect the level of thyroxine hormone and metamorphosis.

Explanation of Solution
The pituitary gland secretes thyroid-stimulating hormone (TSH). TSH signaling is initiated in the early tadpole. This stimulates the thyroxine secretion that binds with the gene for expressing proteins for metamorphosis. If hypophysectomy is performed in late tadpole then it will not affect the metamorphosis or thyroxine level because in late tadpole pituitary hormone is not required.
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Chapter 44 Solutions
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