. Biology; the story of living things. 370 THE MAINTENANCE OF THE INDIVIDUAL â¢>i*'':-: â â¢â .-â - â *â â â ."â â ,â ..." â¢â¢â ^{;.-'. â ⢠» >⢠», â¢â¢ V;.. ,.â â â¢,'â .â â â â â â â¢...'-J,' â¢>â â â ⢠â -'â¢;â '. Francis B. Sumner Dr. Sumner's experiments with flounders show a response of the animal to different backgrounds. How would you attempt to account for this .â¢* environment by chang- ing their color pattern. There may even be elec- tric responses to stimuli as seen in the discharge of as much as 300 volts from the electric organ of the electric eel, a s
. Biology; the story of living things. 370 THE MAINTENANCE OF THE INDIVIDUAL â¢>i*'':-: â â¢â .-â - â *â â â ."â â ,â ..." â¢â¢â ^{;.-'. â ⢠» >⢠», â¢â¢ V;.. ,.â â â¢,'â .â â â â â â â¢...'-J,' â¢>â â â ⢠â -'â¢;â '. Francis B. Sumner Dr. Sumner's experiments with flounders show a response of the animal to different backgrounds. How would you attempt to account for this .â¢* environment by chang- ing their color pattern. There may even be elec- tric responses to stimuli as seen in the discharge of as much as 300 volts from the electric organ of the electric eel, a shock sufficient to kill a horse. In the higher animals where well-developed or- gans have been evolved, an organ is usually at- tuned to one kind of stimulus and responds only to that particular stimulus. The eye, for example, responds to light waves, but to no other ether waves, while the organ of Corti in the mam- malian ear distinguishes with accuracy betw^een different wave lengths which cause sounds. Thus the nature of responses depends not upon the stimulus, but upon the kind of cells stimulated. Mechanisms of Response in Plants It is much easier to show that plants respond to stimuli than to explain how they do. Most of the responsive activities of plants do not, as one author puts it, result in "discriminating movement" so much as in ''discriminating ; If a growing root is photo- graphed every ten or fifteen minutes and these pictures greatly magnified are projected as a slow motion motion picture, the root seems to act like an intelligent "white worm," pushing aside soil particles, avoiding obstacles, and ultimately finding its way to an area where water Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original
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