Presentation on theme: "If it is to be, it is up to me!"— Presentation transcript:
1If it is to be, it is up to me! College KnowledgeCollege adds over $1Million to your lifetime family income…But only if you grow up now to take advantage of this opportunity!Your Middle and High School teachers are there to help you open this door…You need to accept their help!Heed their advice!If it is to be, it is up to me!
2Notice, like you, I have TWO EYES! I’mRoss KoningProfessor of BiologyatEastern ConnecticutState UniversityBiology DepartmentPhD 1981University of MichiganI teach the introductory biology course for biology majors here.Notice, like you, I have TWO EYES!Are they identical?
3Use both eyes…at arm’s length, center target within finger OK sign Lock hand in position…see which eye is still aligned by closing the otherThe eye with good alignment is your dominant eye!
4Insects appear to have two eyes also, but they are compound! Figure 46-7Insects appear to have two eyes also, but they are compound!Each ommatidium sends separate information to their brain.Ommatidia are the functional units of insect eyes. Ommatidia contain receptor cells that send axons to the CNS.OmmatidiaLensReceptor cellsAxons4
5Copyright Norton Presentation Manager Human vs Insect VisionCopyright Norton Presentation Manager
6Spiders have up to 8 eyes looking in different directions!! It makes you wonder what exactly they see!
8Try with BOTH eyes open…do you have a blind spot now? Why not? Use right eye only (close left eye)…focus only on the target for this test!Lock head in position…hold one finger up at arm’s length to cover view of targetMove arm slowly outwards from target (to right for right eye)Find your blind spot for that eye…is it only off to ONE side? try the other side!Does the blind spot extend upwards or downwards?Try with your left eye…is its blind spot on the same side or on the other?Try with BOTH eyes open…do you have a blind spot now? Why not?
9Use right eye only (close left eye)…our target is a row of numbers Focus on each number in turn, until the break in the blue lines is in your blind spot. What is different when the blind spot holds a blank area?
11Figure 46-8 11 The structure of the vertebrate eye. In the retina, cells are arranged in layers.Pigmented epitheliumGanglion cellsConnecting neuronsPhotoreceptor cellsScleraRetinaIrisDirection of lightPupilCorneaFoveaLensOptic nerve (to brain)Axons to optic nerve11
12Figure 46-9The Cephalopod EyeRetina (photoreceptors are on the inside surface)CorneaLensSensory nerves to brainThis “design” is “more intelligent” than that of mammals (humans) because it lacks the blind spot and maximizes light exposure to receptors12
15Rods and cones contain stacks of membranes. Figure 46-10Rods and cones contain stacks of membranes.Rhodopsin is a transmembrane protein complex.Opsin (protein component)Retinal (pigment)ConeRod0.5 µmRhodopsinLightLightThe retinal molecule inside rhodopsin changes shape when retinal absorbs light.trans conformation (activated)cis conformation (inactive)OpsinOpsinLight15
16Use both eyes, stare at area shown in blue for 15 seconds or so
17What do you see on this blank white slide? Blink if needed! This is called an “after image”Does it move around as you move your gaze?
18Light: An Energy Waveform With Particle Properties Too wavelengthvisible spectrumnmwavelength (nm)10-9 metermeter!