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aboral side acid action system activities Amoeba anode attached avoiding reaction bacteria bacterium become bend body carbon dioxide cathode cause ceases changes in behavior character chemical cilia collect contact reaction continues contraction course determined direction of movement disk effect electric current Euglena external conditions fact factors favorable flagella flatworm food reaction heat higher animals Hydra individuals induced infusoria injurious interference long axis lower organisms medusa ment metabolic Metazoa method mouth move negative reaction objective observed occurs optimum oral side orientation oxygen Oxytricha Paramecia Paramecium pass peristome positive reaction processes produced protoplasm Protozoa pseudopodium react reaction to gravity reaction to light reflex region regulatory result reversal sea anemones sea urchin seen shown solid solution source of light species specimens spiral Stentor stimulating agent substances surface swarm spores swim backward swims forward temperature tentacles tion trial trichocysts tropism tube turning usually varied movements Vorticella
Página 175 - We have now reached a specially interesting point in the experiment. Suppose that the water currents again bring the carmine grains. The stimulus and all the external conditions are the same as they were at the beginning? Will the Stentor behave as it did at the beginning? Will it at first not react, then bend to one side, then reverse the current, then contract, passing anew through the whole series of reactions? Or shall we find that it has become changed by the experiences it has passed through,...
Página 186 - We are neither of these, but simply investigators of earnest purpose and unbiassed mind, who study all things, prove all things, and hold fast to that which is good. We seek, inquire, reject nothing without cause, accept nothing without proof: we are students, not teachers.
Página 266 - This orientation is produced, according to this tropism theory, by the direct action of the stimulating agent on the motor organs of that side of the body on which it impinges. A stimulus striking one side of the body causes the motor organs of that side to contract or extend or to move more or less strongly. This, of course, turns the body till the stimulus affects both sides equally; then there is no occasion for further turning and the animal is oriented" (JENNINGS 19063, p. 266). This is also...
Página 179 - The same individual does not always behave in the same Universality way under the same external conditions, but the behavior of tbl3 depends upon the physiological condition of the animal. The reaction to any given stimulus is modified by the past experience of the animal, and the modifications are regulatory, not haphazard in character. The phenomena are thus similar to those shown in the learning...
Página 19 - We find that the simple naked mass of protoplasm reacts to all classes of stimuli to which higher animals react (if we consider auditory stimulation merely a special case of mechanical stimulation).
Página 291 - The operations of this law are, of course, seen on a vast scale in higher organisms in the phenomena which we commonly call memory, association, habit formation and learning.
Página 338 - ... JENNINGS. The results set forth in the preceding paper, together with certain other relations found in the behavior of lower organisms, that have been detailed in previous papers by the present writer, suggest a certain point of view in regard to the general method of regulation or adjustment in organisms. Everywhere in the study of life processes we meet the puzzle of regulation. Organisms do those things which advance their welfare. There are some exceptions, but this is certainly true in a...
Página 342 - ... the injurious action, provided such a condition exists. Thereupon the changes in behavior cease, and the organism remains in the favorable condition. The movements of the organism when stimulated are such as to subject it to various conditions, one of which is selected. This...
Página 101 - If a bit of filter paper is placed in a preparation of Paramecia, the following behavior may often be observed. An individual swims against it, gives the avoiding reaction in a slightly marked way, swimming backward a little; then it swims forward again, jerks back a shorter distance, then settles against the paper and remains. After remaining a few seconds, it may move to another position, still remaining in contact with the paper. Then it may leave the paper and go on its way.
Página 266 - The light operates, naturally, on the part of the animal which it reaches. The intensity of the light determines the sense of the response, whether contractile or expansive; and the place of the response, the part of the body stimulated, determines the ultimate orientation of the animal.