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Taxis and Tropism: response of organism towards the stimuli

Taxis and tropism, What is taxis? What is tropism? What is kinesis? What is kinetic response? What is taxic response? What is tropic response? Klinotaxis, Tropotaxis, Telotaxis, Menotaxis, Mnemotaxis, phototropism, phototaxis chemotaxis rheotaxis

What is taxis?

Taxis or taxic response is a directional movement of the whole organism in response to an external directional stimulus.

What is kinesis?

Kinesis or kinetic response is a non-directional movement in which the rate of movement is related to intensity of stimulus and not to the direction of stimulation, e.g. the movement of tentacles of Hydra.

What is tropism?

Tropism is the turning movement in plants and sessile animals in response to stimulus.

Here are some taxis and related stimulus with their positive and negative responding organisms.

Types of taxis Movement due to Examples (+ve) Examples (-ve)
Phototaxis light Euglena, fruit flies, fire flies Cockroach, Earthworm
Hydrotaxis Water Fish Land animals
Aerotaxis Air (oxygen) Motile aerobic bacteria Anaerobic bacteria
Chemotaxis Chemicals Euglena exposed to glucose or weak acid solution Euglena exposed to salt/strong acid solution
Geotaxis Gravity Amoeba falls on the bottom of container having water/ Planula larva moves towards sea bed Ephyra larva of Jelly fish, swims away from sea bed.
Rheotaxis Air/water current Birds moves along the air current Planaria moves against water current
Hygrotaxis Moisture Earthworm moves towards the moist place Desert animals moves away from the moist place
Galvanotaxis Electric current Paramecium moves towards cathode where weak electric current is supplied. Man moves away from the electric current
Sociotaxis Colony or group Colonial animals Solitary animals
Thigmotaxis Touch Dogs come closer if touched with human hands Paramecium moves away if touch by some solid objects
Thermotaxis Temperature Planaria shows movement in response to temperature Migration of birds to escape the extreme temperature

Some important taxis

Klinotaxis is movement in which animals try to orient their body by comparing intensities of stimulation on two sides of the body. Eg. Euglena, Planaria, earthworm,etc. It is generally shown by organisms that bears sensory receptors but no sense organs.

Tropotaxis is behavioral response of bilaterally symmetrical animals due to stimulus leading to orientation of the body straight towards the stimulus. Eg. Grayling butterflies, Argulus (fish louse), etc.

Telotaxis is the orientation of a bilaterally symmetrical animal at any one of the stimuli but not intermediate or both when two sources of stimuli of same intensity operate at the same time. Honeybee shows this type of taxis.

Menotaxis is the orientation of the body in response to stimulus at a constant angle. It is also known as light compass response.

Mnemotaxis is the orientation of animals depending on some complex stimuli like direction, landmarks, etc. Eg. Hunting wasps. HINT TO LEARN: p ronunciation of mnemotaxis is complex= so learn it as complex stimulus.

You might like these contents:

Mnemonics for False fishes

Different biological theories and their propounders

Mnemonics for the malarial disease, causative organisms and dots of plasmodium

Best wishes

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