Two modes of adaptation

Adaptation is a biological process that involves adjusting to the current conditions of the environment that the organism is in.  The adjustments of the organism are necessary for the organism to survive in the current environment.

An organism will alter specific biological conditions within his body in order to manage the external conditions that he is facing, including changes in temperature, heat and sunlight.  In addition, an organism will also adapt to the current conditions of the air, water and food in the environment.  An organism will also modify mechanisms that are related to reproduction and environmental insults such as pollution and drought.

Two modes of adaptation have been described in the field of biology.  Structural adaptations pertain to changes in particular parts of the body of an organism that will facilitate survival of the organism in a specific environment.

Structural adaptation may involve modifications in the color of the skin or changes in the covering of an organism’s body.  Behavioral adaptations relate to methods that an organism will execute in order to function at its normal conditions.  This may include regulating the amount of salts within the body of an organism in order to retain the amount of water in its body.

The experiments involving the sandpaper, sugar water and hot and cold water directly show that the human body has a great ability to adapt to changes in its environment.  The sensory perception of coarseness had disappeared during the second time that my index finger rubbed the coarse sandpaper.

The sugar water altered my perception of sweetness, thus the fresh water tasted sweet also.  My hands also adapted to the current temperature of the water in the bowls, which was either hot or cold, and this resulted in a different sensation of the temperature of the middle bowl which contained a mixture hot and cold water.

The three experiments describe the process of sensory adaptation which mainly involves the persistent usage of receptors.  Sensory adaptation is different from perceptual adaptation because this involves directing the focus of an organism’s attention elsewhere.

The process of adaptation is strongly associated with the phenomenon of natural selection.  It has been described that adaptation involves making use of specific capabilities of an organism’s body in order to survive and cope with alterations, perturbations and pressure in its immediate environment.  It is also interesting to know that specific adaptations are lost if the adjustment is not needed for the survival or normal functioning of the organism to the environment.

A good example here is the adaptation of the human body to different seasons of the year.  During summer when the temperature is hot, the body tends to sweat a lot in order to release the heat that is building up within the body.  However, during the fall and winter seasons, the human body adapts to the cold weather hence there is no more need for the body to sweat.

Different sensory receptors are present in the body.  In the sugar water experiment, the taste or gustatory receptors were involved in determining the taste of the solution.  Taste receptors are located in the taste buds of the tongue.  These are situated in the tongue because the mouth is the primary organ that interacts with food consumption.  Four major taste sensations are present, including sweet, salt, sour and bitter.

The taste receptors are significantly influenced by smell receptors, temperature receptors and feeling receptors.  Hence it is interesting to know that an individual can feel so many sensations from the simple act of eating a particular food item.

There are tactition or mechanoreceptors on the surface on the palms of our hands which can determine the smoothness or coarseness of a surface.

The sensory receptor that perceives temperature is called a thermoreceptor.  This specific type of receptor activates the skin, eyes and urinary bladder upon reception of a message regarding the temperature of a certain item or condition.

Any change in temperature influences the hypothalamus to start thermoregulation of the body as a response to the observed temperature.  The cold sensation is sensed by cold-sensitive thermoreceptors, while the hot sensation is felt by heat-sensitive thermoreceptors.

The sensory receptors for hearing are situated in the ear, which is composed of three major areas that are responsible for sound conduction (Ardley, 1992).  The pinna, external auditory canal and the eardrum or tympanic membrane are outer ear structures that serve as the receptacle for sound.  The ossicles and auditory tube are the middle ear structures that relay the vibrations that are received from the eardrum.  The pressure created is equalized by the auditory tube.

The cochlea, vestibule and semicircular canals are inner ear structures that are responsible for maintaining equilibrium to the rest of the body.  The hearing receptors are situated along the membranes of the cochlea.  In addition, the organ of Corti is another hearing receptor located in the cochlea that is activated by vibrations that come from the air, fluids and membranes.

  When there is an abnormal disturbance to the external and middle areas of the ear, hearing loss is experienced.  In addition, if there is any damage to the nerve structures that are present in the ear, deafness ensues.


Ardley, N. (1992) The science book of the senses. San Diego: Harcourt Brace Jovanovich.