Q1. [3] deep thorough-understanding
A student argues: 'Since reflex arcs evolved because the brain is too slow, animals with highly developed brains should eventually lose their reflex arcs as they become unnecessary.' Do you agree? Justify your answer using your understanding of how reflex arcs and the brain function together.
Generated by claude-sonnet-4-6 · 2026-06-26 01:00 · grounding rag
Model Answer
No, I do not agree.
Reflex arcs did evolve because the brain's thinking process is too slow for urgent responses. However, even after complex neuron networks developed, reflex arcs continue to be more efficient for quick responses. For example, pulling a hand away from a flame via the spinal cord is faster than routing signals to the brain for conscious decision-making. The reflex arc and brain work together — the information also travels to the brain, but the protective action is completed instantly. Thus, reflex arcs remain essential even in animals with highly developed brains.
Source: Chapter 6, Section 6.1.1 – What happens in Reflex Actions?
---
Explanation
- The key quote to remember: "even after complex neuron networks have come into existence, reflex arcs continue to be more efficient for quick responses."
- Examiners want you to clearly state disagreement, give the reason (speed/efficiency), and show understanding that both systems work together (information goes to brain AND the reflex arc acts simultaneously).
- Avoid just defining reflex arc — the question asks for justification of whether they become unnecessary. Address that directly.