Chapter 5 Self-test questions

. Which of the following statements describe correctly the physical properties of ultrasound? Please select all that apply.

Ultrasound is defined by frequencies above the frequency range of human hearing.

Due to its short wavelength, ultrasound is well suited for the detection of small objects.

The speed of ultrasound is significantly higher than the speed of sound in the frequency range of human hearing.

Ultrasound is subject to a much stronger atmospheric attenuation than sound in the frequency range of human hearing.

. Which of the following scientists have contributed to the discovery of echolocation in bats? Please select all that apply.

Lazzaro Spallanzani

Francis Crick

Hamilton Hartridge

Donald R. Griffin

. Which of the following descriptors is not characteristic of FM sounds, compared to CF components of sound, produced by bats?

Long pulses that cover a narrow range of frequencies.

Short pulses that cover a broad range of frequencies.

Both pulse duration and frequency range can be modulated according to the behavioral situation.

Well suited for measuring the time delay between the emitted pulse and the returning echo.

. Which of the following statements regarding estimation of target distance by echolocating bats is not correct?

The computation of target distance is based on the measurement of pulse-echo delays.

For the determination of the delay time between the emitted pulse and the returning echo a single measurement at the mean frequency of the sound is taken.

For the determination of the delay time between the emitted pulse and the returning echo multiple measurements at different frequencies are taken.

FM-FM neurons in the inferior colliculus of bats typically produce one action potential each in response to the emitted pulse and the returning echo, if the pulse-echo delay occurs within the time interval these neurons are tuned to.

. Finish this sentence correctly: Assuming a velocity of sound of 344m/sec, a pulse-echo delay of 2msec corresponds to a distance between the bat and the object of

172 mm.

344 mm.

688 mm.

172 m.

. The FM-FM area of the auditory cortex of bats is a special case of a computational map.

True

False

. Doppler shifts involve a shift in frequency and occur whenever the source of any kind of propagating energy, such as light or sound, moves in relation to the receiver of this energy.

True

False

. Which of the following statements in regard to Doppler shifts experienced by the greater horseshoe bat (Rhinolophus ferrumequinum) is correct?

The bat experiences Doppler shifts only if it flies toward a stationary object, but not if it is stationary and the object moves.

When the bat emits sonar sound at 83kHz while approaching a target, then the frequency of the returning echoes shifts toward lower values.

Doppler shift compensation is a behavioral mechanism for ensuring that the frequency of the echo is kept in the range of most sensitive hearing of the bat.

The bat performs Doppler shift compensation in response to Doppler shifts produced both by the relative motion of an insect in the bat's flight path and by the wing beats of this insect.

. Which of the following statements related to the place theory of hearing is not correct?

In the cochlea, sound frequency is encoded by the position of the hair cells along the basilar membrane.

In the cochlea of the greater horseshoe bat (Rhinolophus ferrumequinum), sound frequencies are represented along the basilar membrane in a linear fashion.

'Acoustic fovea' refers to a structural expansion of the basilar membrane in the cochlea to accommodate perception of frequency components of sound that are of particular behavioral significance.

In the greater horseshoe bat, overrepresentation of frequencies relevant for echolocation has been found in the cochlea, among first-order neurons that innervate the cochlea, and in the auditory cortex.

. Which of the following counter-adaptations to avoid predation by echolocating insectivorous bats has not been developed by insects?

Tympanic organs with sensitivity in the ultrasonic frequency range.

Behavioral avoidance responses, such as movements away from the source of ultrasonic sound and erratic flight maneuvers.

Production of high-frequency clicks by means of tymbal organs.

Complex eyes with sensitivity in the infrared range of light.

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