A student claims: 'Animals do not need hormones for controlling growth because, unlike plants, animals do not show directional growth.' Evaluate this claim using specific examples from the human endocrine system.
Generated by claude-sonnet-4-6 · 2026-06-26 01:03 · grounding rag
Model Answer
The student's claim is incorrect. Animals do need hormones to control growth and many other vital functions.
Examples from the human endocrine system:
- Growth Hormone (GH): Secreted by the pituitary gland, it directly controls overall body growth. Deficiency causes dwarfism; excess causes gigantism.
- Thyroxin: Released by the thyroid gland, it regulates metabolism and body development. Deficiency in children causes stunted growth (cretinism).
- Sex hormones (e.g., oestrogen/testosterone): Control puberty changes like increased height, breast development, and reproductive maturity — all forms of growth.
Thus, hormones regulate growth, metabolism, and reproduction in animals, disproving the claim.
Source: Chapter 6, Chemical Coordination; Chapter 7, Section 7.3.3
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Explanation
- The examiner wants you to refute the claim clearly, then support with specific hormone examples with gland, function, and effect of deficiency/excess.
- The passage confirms chemical coordination occurs in both plants and animals, so hormones are essential in animals too.
- Mentioning puberty changes (from Ch. 7) directly links hormones to growth in animals — a strong, text-based example.
- Avoid vague statements; name the hormone, its source, and its role for full marks.