Lecture 6: Nervous System and Perception

Question 1

What are the disadvantages of pinhole eye?

Answer 1

Only a tiny amount of light enters eye, diffraction or bending of light at edges reduces quality of an already- dim image.

Question 2

What are the disadvantages of a lens eye?

Answer 2

unique focal point, compensated for by muscles which alter the shape of lens and change focal point; complicated neural wiring required; anatomical defects more likely such as short or far sighted and astigmatism.

Question 3

What is flicker-fusion rate?

Answer 3

ability to distinguish two separate images closely spaced in time.

Question 4

Is the sensory environment more species-specific for vision or hearing?

Answer 4

Animal vision runs from ultra violet to infrared a factor of 2 in wavelength; animal hearing runs from 0.1 Hz to 100,000 Hz, a factor of a millino in wavelenght.

Question 5

What is a limitation of a particle-detector eat?

Answer 5

Limited resonance frequency thus deaf to most sounds

Question 6

How can the limited resonance frequency be overcome?

Answer 6

By using several detectors of different resonances

Question 7

What is a second limitation of a particle detector ear?

Answer 7

Cannot distinguish between a relatively quiet sound a peak resonance and a loud sound close to the frequency of the peak resonance.

Question 8

What is a third limitation of a particle detector eat?

Answer 8

Deaf to sounds coming from the direction in which detector pointed; most sensitive to sounds striking it from the side.

Question 9

How can the limited directional detection be overcame?

Answer 9

Turning to try the other orientations for comparisons; using a second detector with a different orientation and performing trigonometry to determine direction ie. 2 antennaes

Question 10

What happens if the tube like cavity lies across the direction of sound propagation?

Answer 10

No pressure diff; thus the ear is deaf

Question 11

Do low or high frequencies travel further?

Answer 11

low frequencies which have longer wavelengths

Question 12

True or False? Frogs have pressure gradient ears.

Answer 12

True

Question 13

How does the external ear facilitate localization of sound?

Answer 13

Sound bounces of lumps ridges arriving at diff times of ear drum

Question 14

How is the motion of sound judged?

Answer 14

Doppler effect: movement of sound toward or away from listener artificially shortens or lengthens the pressure waves.

Question 15

What are the four classes of taste receptors and their pirest stimuli in humans?

Answer 15

Salt, sour, bitter, sweet

Question 16

What is possible 5th class of taste receptor in humans?

Answer 16

umami (MSG)

Question 17

How do insects typically find food?

Answer 17

By stepping on it.

Question 18

Where do rattle snakes strike when anesthetized mice are dragged either forward or backward?

Answer 18

Usually anterior portion regardless of direction of movement.