If you enter a darkened room from a lighted area, you cannot see anything. The retina of the eye is lacking sufficient light-sensitive rhodopsin in the rods for adequate vision. However, the concentration of rhodopsin builds up quickly, as you can see from the graph in Figure 36–1 showing dark and light adaptation.

23. How is the response of the retina to changes in light an adaptation? Refer to Figure 36–1.

Question

If you enter a darkened room from a lighted area, you cannot see anything. The retina of the eye is lacking sufficient light-sensitive rhodopsin in the rods for adequate vision. However, the concentration of rhodopsin builds up quickly, as you can see from the graph in Figure 36–1 showing dark and light adaptation.




23.   How is the response of the retina to changes in light an adaptation? Refer to Figure 36–1.

anonymous · Answer

Some millenniums ago, some of our ancestors has this trait of quickly-accumulating rhodopsin (due to mutation), while others did not. Because the former could see better at night, he had a better chance of long-term survival. Since the organisms lacking this trait died (perhaps eaten because they couldn't see the nighttime predator coming), the mutation that allowed the survivors to live on has been passed down through the years. That's what evolution is.