Dogs and horses are only able to sec images in black and white. Give a reason wh

Question

Dogs and horses are only able to sec images in black and white. Give a reason why this might be the case. Explain the scientific basis for the saying "All cats are gray in the dark." Which photoreceptors are primarily responsible for dark adaptation? Explain how dark adaptation works. How does the retina of a person who is red-green color-blind differ from the retina of a person with normal color vision? Explain why older people complain that their arms seem to be getting shorter when they pick up something to read.

Explanation / Answer

4.

5.

The phrase all cats are grey in the dark means that in the dark, physical appearance is unimportant.

6.

7.

·        The retina of the eye has two types of light-sensitive cells called rods and cones. Both are found in the retina which is the layer at the back of the eye which processes images.

·        Rods work in low light conditions to help night vision, but cones work in daylight and are responsible for colour discrimination.

·        There are three types of cone cells and each type has a different sensitivity to light wavelengths. One type of cone perceives blue light, another perceives green and the third perceives red. When one looks at an object, light enters the eye and stimulates the cone cells. The brain then interprets the signals from the cones cells so that one can see the colour of the object. The red, green and blue cones all work together allowing to see the whole spectrum of colours.

·        That colour blindness is usually caused by faulty cones but sometimes by a fault in the pathway from the cone to the brain.

·        People with normal colour vision have all three types of cone/pathway working correctly but colour blindness occurs when one or more of the cone types are faulty.For example, if the red cone is faulty you won’t be able to see colours containing red clearly.

Related Questions

Navigate

• Browse (All)
• Browse D
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.