[Campbell Biology P.1164] Based on Figure 50.12 and its accompanying text, if a musical chord... | Practice Question

Based on Figure 50.12 and its accompanying text, if a musical chord consists of notes with frequencies of 100 Hz, 1,000 Hz, and 6,000 Hz, what is the most accurate description of the basilar membrane's activity and the resulting perception?

  • A: Only the region for 6,000 Hz will vibrate significantly, as it's the highest frequency, making it difficult to distinguish the lower notes.
  • B: The entire basilar membrane will vibrate uniformly at an average frequency, leading to a blended, indistinguishable sound.
  • C: Different regions of the basilar membrane will vibrate maximally at distinct locations corresponding to each frequency, allowing the brain to perceive the chord as individual, distinct notes.
  • D: The vibrations will be too complex for the ear to distinguish individual notes, and only the dominant frequency will be perceived.

Explanation

Figure 50.12 b demonstrates that different frequencies cause maximal vibration at distinct points along the basilar membrane. High frequencies 6,000 Hz vibrate closer to the oval window Point A , medium frequencies 1,000 Hz at a middle point Point B , and low frequencies 100 Hz further from the oval window Point C . When a chord is played, all these distinct regions vibrate simultaneously, sending separate signals to the brain, which it then integrates to perceive the individual notes of the chord.