college knowledge college adds over $1million to your lifetime family income… but only if you grow...
TRANSCRIPT
College Knowledge
College 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!
I’m
Ross KoningProfessor of Biology
at
Eastern ConnecticutState University
Biology Department
PhD 1981University of Michigan
I teach the introductory biology course for biology majors
here.
Notice, like you, I have TWO EYES!
Are they identical?
Use both eyes…at arm’s length, center target within finger OK signLock hand in position…see which eye is still aligned by closing the otherThe eye with good alignment is your dominant eye!
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Figure 46-7
Ommatidia are the functional units of insect eyes. Ommatidia contain receptor cells that send axons to the CNS.
Lens
Receptor cells
Ommatidia
Axons
Insects appear to have two eyes also, but they are compound!Each ommatidium sends separate information to their brain.
Human vs Insect VisionC
opyr
ight
Nor
ton
Pres
enta
tion
Man
ager
http://farm5.static.flickr.com/4010/4682587135_b91e399914.jpg
Spiders have up to 8 eyes looking in different directions!!
It makes you wonder what exactly they see!
Vertebrate Eye
blind spot
Cop
yrig
ht N
orto
n Pr
esen
tatio
n M
anag
er
controls light
focuses image
senses image
sends image to brain
What?
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?
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Use 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?
1 2 3 4 5 6 7 8 9
blind spot
Figure 46-8
The structure of the vertebrate eye. In the retina, cells are arranged in layers.
Ganglion cells Connecting neurons Photoreceptor cellsPigmented epithelium
Retina
Direction of light
Fovea
Optic nerve (to brain)
Sclera
Iris
Pupil
Cornea
Lens
Axons to optic nerve
Figure 46-9
Cornea Lens
Retina (photoreceptors are on the inside surface) Sensory
nerves to brain
The Cephalopod Eye
This “design” is “more intelligent” than that of mammals (humans) because it lacks the blind spot and maximizes light exposure to receptors
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Eye Evolution
Vertebrate Retina
cone
rod
light
Figure 46-10
Rods and cones contain stacks of membranes. Rhodopsin is a transmembrane protein complex.
Cone Rod
Light Light
Rhodopsin
Retinal (pigment)
Opsin (protein component)
The retinal molecule inside rhodopsin changes shape when retinal absorbs light.
Light
trans conformation (activated)
Opsin
cis conformation (inactive)
0.5 µm
Opsin
Use both eyes, stare at area shown in blue for 15 seconds or so
What 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?
Light: An Energy Waveform With Particle Properties Too
wavelength (nm)10-9 meter
0.000000001 meter!
400 500 600 700 nm
wavelength
visible spectrum
Vertebrate Retina
cone
rod
light
Figure 46-13Visible spectrum
S opsin 420
M opsin 530
L opsin 560
Use both eyes, stare at the parrot’s eye for 15 seconds or so
What color is the bird in the cage?Blink if needed
Use both eyes, stare at the parrot’s eye for 15 seconds or so
What color is the bird in the cage?Blink if needed
Use both eyes, stare at the parrot’s eye for 20 seconds or so
What color is the bird in the cage?This color is a bit harder to visualize
Use both eyes, stare at the white dot for 20 seconds or so
http://www.cagle.com/working/100427/cagle00.gif