https://padlet.com/patty_weber/tcwdq7562jby en-us 2016-11-17 16:33:38 UTC 2025-09-28 02:45:18 UTC hello@padlet.com patty_weber https://padlet.com/patty_weber/tcwdq7562jby/wish/138468104 Part 1: How does human vision compare to other mammals? Provide specific examples. 
Part 2:
--Find evidence to support Young-Helmholtz's Trichromatic Theory.
--Find evidence to support the opponent-process theory.
Part 3: 
Which theory do you think best explains color vision? Explain. 
Cite any sources you use (outside of the textbook) in APA format. ]]> 2016-11-17 16:34:23 UTC https://padlet.com/patty_weber/tcwdq7562jby/wish/138468104 https://padlet.com/patty_weber/tcwdq7562jby/wish/211991290 Part 1:  Cats vs Humans
The biggest difference with cats and humans is the retina. Cats have a high concentration of rod receptors and a low concentration of cone receptors. While humans have the opposite which is why we can't see as well at night, but we can detect colors better. Cats can see in the dark very well, because of there high number of rods in their retina that are sensitive to dim light. A cats vision (with color) is similar to a colorblind human. (red and pink are confusing) 
Dogs vs Humans 
Dogs are very near sighted compared to humans. 
Horses vs Humans
Horses like dogs, cannot perceive the difference between red and green. They also have similar rate of vision to a dog. Horses have more rods than humans, a high proportion of rods to cones, as well as a tapetum lucidum, giving them superior night vision
Eagle VisionsVs. Human Vision
Eagles and other birds of prey are the kings of visual acuity. Their retinas are not only packed with light detecing cone cells, but they also have a much deeper fovea. Which acts like a telephoto lens on a camera. Their cornea also has the ability to change shape to better focus on near and far objects. ]]> 2017-11-30 18:06:52 UTC https://padlet.com/patty_weber/tcwdq7562jby/wish/211991290 https://padlet.com/patty_weber/tcwdq7562jby/wish/211999288 Part 2: 
Hermann von Helmholtz developed the theory further in 1850: that the three types of cone photoreceptors could be classified as short-preferring (blue), middle-preferring (green), and long-preferring (red), according to their response to the wavelengths of light striking the retina. The relative strengths of the signals detected by the three types of cones are interpreted by the brain as a visible color.

opponent-process theory, The colors in each pair oppose each other. Red-green receptors cannot send messages about both colors at the same time. This theory also explains negative afterimages; once a stimulus of a certain color is presented, the opponent color is perceived after the stimulus is removed because the anabolic and catabolic processes are reversed. For example, red creates a positive (or excitatory) response while green creates a negative (or inhibitory) response. These responses are controlled by opponent neurons, which are neurons that have an excitatory response to some wavelengths and an inhibitory response to wavelengths in the opponent part of the spectrum.]]> 2017-11-30 18:20:45 UTC https://padlet.com/patty_weber/tcwdq7562jby/wish/211999288 https://padlet.com/patty_weber/tcwdq7562jby/wish/212984466 I like the opponent-process theory because I feel like it explains it better. ]]> 2017-12-04 17:53:01 UTC https://padlet.com/patty_weber/tcwdq7562jby/wish/212984466