Human anatomy is complex and thus there are several reactions within the bodies of these multicellular organisms, there are several movements which are not visible or might be taken as usual but they are not noticed much.
Stimulus plays an important role in creating such movements, stimulus is a physiological phenomenon which is a detectable change in the physical or chemical structure of an organism’s external or internal environment. For example, hit the needle to skin and the response of the body will be sudden movement.
The stimulus can be environmental as well for example sun, water, air, soil, etc.. They also affect the movements in the animal body, for example when the sunlight feels too warm on the body the animal trends to move in the direction of shade or cool environment.
The person might not notice the movement but it took an internal reaction to produce this response, likewise, there are other responses as well for stimulus. There are generally two types of motions when responding to a stimulus, those ar; taxis and kinesis.
Taxis vs Kinesis
The main difference between taxis and kinesis is that the taxis have a specific type of motion that is directed; on the other hand, kinesis has random and undirected motion. Both of them respond to stimulus and are found in living beings like animals and insects.
Comparison Table Between Taxis and Kinesis
| Parameters of Comparison | Taxis | Kinesis |
| Type of movement | Specific direction | No specific direction |
| Direction of movement | Towards or away from the source of stimulus. | Random direction from a source of stimulus. |
| Types | Phototaxis, aerotaxis, geotaxis, thigmotaxis, etc.. | Orthokinesis and klinokinesis |
| Rate of dependency on stimulus | Less dependent on stimulus intensity. | More dependent stimulus intensity. |
| Examples | Euglena or humans, etc.. | Lice or beetle, etc.. |
What is Taxis?
Taxis is the biological behavioural response of a cell or an organism to an external stimulus, which may be towards or away from the source of stimulus. The attraction and repulsion from the source of a stimulus depend upon the organism’s brain.
There are several types of taxis identified; aerotaxis, anemotaxis, barotaxis, chemotaxis, durotaxis, galvanotaxis, gravitaxis, hydrotaxis, magnetotaxis, phonotaxis, phototaxis, rheotaxis, thermotaxis, thigmotaxis, etc..
In taxis like thermotaxis, the animal would respond to the temperature stimulus, in phototaxis the animal would respond to light stimulus, in chemotaxis the animal would respond to any chemical stimulus, in thigmotaxis the animal would respond to touch or contact, and so on.
There are two types of movements in taxis that are positive and negative. Positive movement is said when the movement is towards the source of stimulus and negative is said when the movement is away from the source of stimulus. The response is common in every animal but still, some exceptions are there.
The normal animal behaviour depends on their surroundings and thus the animal brain responds differently in every situation and stimulus. The behaviour also varies from animal to animal. Taxis movements are present in animal behaviour and can be seen in regular life as well.
Some examples of taxis are; euglena move towards light source which can be classified as phototaxis, any person touching something warm will suddenly move his hand backwards this can be classified as thigmotaxis, and so on. These movements will occur either towards the stimulus source or away from it.
What is Kinesis?
Kinesis is a biological behaviour or activity of animals responding to stimulus but unlike taxis, kinesis does not have any specific direction movement.
The difference between taxes in kinases lives in the type of movement, in kinesis the movement is random that means it does not have any particular direction like negative or positive or toward or away, the response to a stimulus can produce kinesis in any direction randomly.
There are two types of kinesis, those are; orthokinesis and klinokinesis, wherein the orthokinesis involve the dependence of stimulus to the movement of the individual, and in klinokinesis involves frequency or rate of turning proportional to the intensity of the stimulus.
The stimulus can be of several types within an environment like, temperature, sun, air, water, etc.. everything produces some kind of reaction in the animal body to which they respond accordingly. KInesis is somewhat related or dependent on taxis.
Some examples of kinesis are; lice move to turn far from frequently in the warm area, this means they tend to spend more time in the warmer region which is not a directional response, another example is beetle moving faster in area of light but this is not directional response as some beetles move completely in opposite directions.
Main Differences Between Taxis and Kinesis
- In taxis the direction of response is specific on the other hand in kinesis the direction of response is not specific, rather it is random.
- Taxis have several types like phototaxis, thigmotaxis, geotaxis, chemotaxis, aerotaxis, etc.. On the other hand, kinesis is of two types, those are; orthokinesis and klinokinesis.
- In taxis, movement occurs towards or away but in kinesis, there is no particular direction of movement.
- The rate of taxis is less correlated with the intensity of stimulus. On the other hand the rate of kinesis is dependent on the intensity of the stimulus.
- Some examples of taxis are; the movement of euglena or humans in response to stimulus and few examples of kinesis are; lice or beetles moving faster but not in any particular direction.
Conclusion
Both taxis and kinesis are interlinked, kinesis is more dependent on taxis.
Taxis and kinesis are considered natural phenomena in the animal body, they occur due to chemical reactions within the brain.
External stimulus plays a vital role in both of these biological behaviours of animals. The stimulus can be environmental like sun, water, or air and it can be artificial like animal activities for example contacts and touches.
References
- https://www.sciencedirect.com/science/article/pii/S1476945X18300102
- https://link.springer.com/article/10.1007/s10641-010-9616-y