Comparative Sensory Systems

Modified: 2020-03-18

Sensory systems are not alike throughout the animal kingdom. It is a mistake to assume that our perceptions are similar to the perceptions of other animals. For example, we use blaze orange clothing during deer season to prevent the accidental shooting of hunters. Deer, it turns out, can see blaze orange too, but do not react to it to any degree. Another example involves odor. All of us have a different body odor. Dogs can identify people easily by their body odor, whereas humans have a great deal of difficulty in doing so.

So, sensory systems in different species evolved to meet the ecological requirements of each species. A good example is the eye. Rats' eyes contain only rod cells, or cells that do not detect color, and work best in low light situations. Pigeons' eyes, on the other hand, contain only cone cells, or cells that detect color, but do not work well in low light situations. Now, think of where rats and pigeons live and when they are active. Rats live in burrows and are active at night. Pigeons fly during the day and roost at night. Rats would not make good subjects for color vision studies, but pigeons would. In fact, you can catch a pigeon in a room, if you wait for it to land and then turn off the lights (you need near total darkness). Then you can sneak up on it and grab it.

Finally, all sensory systems can be labelled transducers. Transduction is the process of converting a physical force into neural information. All of the sensory systems transduce physical forces, but each in a different way. The rest of this chapter will consist of detailed descriptions of how that each type of transduction occurs.

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