Name: ________________________________EXAM 3 BIOL L104 BIOLOGY OF THE SENSES NOV. 21, 2013______________________________________________________________________________ANSWER KEY – CORRECT ANSWERS IN BOLDANSWER KEY – CORRECT ANSWERS IN BOLD______________________________________________________________________________1. Which eye parts help focus?b. corneac. lensd. both b and c2. Our perceptions of color (hue) are based on the _____________ of light, while our perceptions of brightness are based on the ________________ of light.a. wavelengths; intensity3. The transduction of light into nervous system signals begins when ________ absorb ________. b. visual pigment molecules; photons4. Which statement about the human retina is FALSE: d. the fovea provides the best visual sensitivity (it actually provides best ACUITY)5. Which does NOT improve night vision? a. making the pupil as wide open as possible (DOES IMPROVE NIGHT VISION)b. a reflective membrane behind the retina (DOES IMPROVE NIGHT VISION)c. a high density of rods (DOES IMPROVE NIGHT VISION)d. ganglion cells with small receptive fieldse. having big eyes with big corneas that bulge out of the head (DOES IMPROVE NIGHT VISION)6. Which of the following statements about glaucoma are TRUE?a. glaucoma results from damage to the ganglion cells which form the optic nerveb. people with glaucoma lose their peripheral vision firstc. glaucoma can sometimes be detected by measuring the pressure in the eye d. untreated, glaucoma can cause total blindness e. all of these statements are true7. Which contains visual pigment molecules that absorb the shortestwavelength photons? a. UV-coneb. L-conec. M-cone- 1 -Name: ________________________________8. The two monsters in this picture are the exact same size. You perceive monster B as smaller than monster A because:a. spatial depth cues in the picture create the illusion that monster A is farther away9. Which eye part expands or contracts to control lens shape and strength?c. ciliary muscle10. Which would NOT produce true color blindness (= seeing only black, white, and grays in the daytime)?a. no cones in the retina (produces true color blindness)b. only L-cones in the retina (produces true color blindness)c. damage to brain areas involved in “color processing” (produces true color blindness)d. only S-cones in the retina (produces true color blindness)e. only S-cones and L-cones in the retina11. To focus light from ______ objects, your lenses need to be ________ and __________.e. nearby; round; strong 12. Your brain uses spatial depth cues tod. create your visual perceptions of distances to objects 13. In visual systems, which cell type transduces?a. photoreceptors14. The image of an object moves across your retinas whenever:a. the object stays still, but your eyes moveb. your eyes stay still, but the object movesd. a and b15. Imagine that the set of relative cone responses to the light hitting one area of your retina is S-cone : 0, M-cone : 1, L-cone : 1. Which color will you most likely perceive for this area of the retinal image? c. bright yellow 16. Imagine that the set of relative cone responses to the light hitting one area of your retina is S-cone: 1, M-cone: 1, L-cone: 1 . Your actual cone responses to this light are medium-low.Which color will you most likely perceive for this area of the retinal image? (Assume that lightness constancy and color constancy are not affecting your color perceptions.) b. gray - 2 -ABName: ________________________________17. In class, you saw pictures and video of a tarsier with forward-facing eyes. What advantage(s) do tarsiers get from having eyes that face forward instead of to the sides?a. enhanced depth perception b. enhanced ability to distinguish objects from background and see past obstaclesd. just a and b18. A function of retinal neurons is:b. to start processing visual information 19. The photo above shows a cat’s “eyeshine” in response to a camera’s flash. His eyes appear to glow because he has ________________ behind his retinas. These structures increase his______________ at the cost of reduced ___________.a. reflective membranes; visual sensitivity; visual acuity 20. Which is false?c. reading in low light conditions can permanently damage your eyes 21. Nearsightedness can be caused by:b. eyeballs that are too long front-to-back22. Fewer than one in a million people are born with only rods (no cones). Which of the following visual problems would such a person have?a. inability to see in bright lightb. poor visual acuityc. no color visiond. all of the above23. What types of photoreceptors are found in the human peripheral retina?d. rods, S-cones, M-cones, and L-cones24. Which contribute to the excellent visual acuity of some birds?a. extremely high cone densities b. two foveas in each eyec. huge eyes d. lots of brain devoted to visual processinge. all of the above- 3 -Name: ________________________________25. According to the article “What Birds See”:a. birds’ retinas contain “oil droplets” that enhance color discriminationb. during a period in their evolution when they were mainly nocturnal, the ancestors of mammals lost two types of conesd. a and b26. Differences in Color Vision Among Species (a) Name an animal that has more types of cones than you: day-active bird, reptile, or fish (1 pt.) (b) Name an animal that has fewer types of cones than you: lots of options, including any other species of mammal except for apes and marsupials(1 pt.) (c) For the animal that has more types of cones than you, what type of photons does the additional cone type detect? (1 pt.) ultraviolet (“u.v.” ) photons. We also accepted “photons of shorter wavelengths than we can detect” (d) Chose one of the species you named above, and explain how its color perceptions differ from yours (1 pt.) Depends on species chosen... With fewer cones types, can distinguish fewer colors. With more cones types, can distinguish more colors. With UV cones,can detect colors based on very short wavelength light that humans can’t see. Answers needed to address color perceptions, not other differences between human and bird vision (like acuity).27. On the diagram of the human eye below: - 4 -Name: ________________________________a) Label the cornea, blind spot, fovea, lens, and pupil. (1 pt. each, 5 pts. total) see