Adaptation is a generic phrase encompassing all changes undertaken by an organism to reduce the negative effects of unfamiliar and undesirable external environment.  This includes both acclimatization and acclimation.

Adaptation describes a spectrum of changes that follow acute and repeated exposure incorporating genotypic (changes within the genome) and phenotypic (within an organism’s physiology) adaptations. It may also include behavioural responses including reduced activity levels.

Acclimatization describes adaptive physiological or behavioural changes within an organism in response to their natural climate or environment.

Acclimation differs from acclimatization in that rather than adaptive characteristics being augmented in a natural climate or environment, the stimuli for adaptation is artificially induced, typically within an enclosed chamber within which ambient conditions (temperature/oxygen content) are altered.

I would just add that "adaptation" however mostly refers to hereditary, genotypic traits, that have evolved through natural selection. "Acclimation"/"acclimatization" ("acclimatisation" in British spelling) refers to phenotypic traits, it is environmentally inducible, and mostly even reversible. Like, when you transfer a plant from climatic conditions A to climatic conditions B, it has to acclimatize.

frequency of hairs in the blade of leaves in some species increase when they grow under direct radiation of sun and reduce in shade( example of acclimation) 

See,

Article Climate change and evolution: disentangling environmental an...

Article The effects of phenotypic plasticity and local adaptation on...

Tow important thinks regarding your question:

 Adaptation refers to  change over several generations (evolutionary process) within a populations or specie.

 Acclimation (controlled conditions)  and acclimatization (natural conditions)  reffers to change during a  lifetime of  given genotype.

The matter is complex and there are lots of misunderstandings. I tried to formulate these concepts systematically in a paper in Plant Science (2013)

Giordano M. (2013). Homeostasis: an underestimated focal point of ecology and evolution. Plant Science 211:92-101; DOI: 10.1016/j.plantsci.2013.07.008. 

Adaptation is where we are .acclimation when we change our geography and environment and acclimitization when we do an experiment on  living being and put them under artificial environment and stress.

no, no , no. 

acclimation is temporary and in short time but adaptation is permanent and in long time

Here you will have some more information as your question is very very complex! Even they are all overlapping processes. Please, give us additional details.

Best

Dr. Lehette

I myself prefer to use adaptation for long-term to adapt the environment to be part of organism phenotypes and acclimation for adaptation to a new natural environment but acclimatization I used this term for adaptation to an artificial environment i.e in the laboratory.

 In marine biology, if one environmental parameter is changed and all the others are maintained in the laboratory (ONLY), we should use the terminology acclimation with no genotypic neither phenotypic changes within one life generation. 

Being a bit "old school" in the way I understand and use these terms, acclimatization refers to a series of physiological responses, that occur gradually over time, which maximize a homeostatic system. Adaptation refers to a shift in genotype and phenotype over generations in response to prolonged environmental pressure.

Acclimation or acclimatization is the process where by an organism adjust in a smooth way to absorb the stress or shock condition that occur in the environment. Normally this occur as an intermediate way for an organism to obtain adaptation and it takes short period of time, some time this can be reversible. 

Adaptation is a result of acclimation which almost  associated with  phenotypic changes and it takes long time, some time permanents.    

The attached file is on the definitions on those terms that make me very confusion. The more bad is the difficulty translate them to Chinese.

http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2486.2012.02797.x/full

acclimation = short-term acute responses 

acclimatization = longer-term chronic responses

adaptive = over generations

There is some reference about the difference between this three terms?

An adaptation is any genetically determined heritable trait (behavioral, morphological or physiological) of an organism that has evolved over a period of time by the process of natural selection such that it maintains or increases the fitness (reproductive and survival) of an organism under a given set of environmental conditions.

Adaptation is different from acclimatization. Acclimatization involves physiological, anatomical or morphological adjustments within a single organism that improve performance or survival in response to environmental change. It occurs in a short period of time (days to weeks), and within the organism’s lifetime. This phenomenon is called acclimation when induced in the laboratory.

Adaptation is related to evolution and, then, to a gene modification. Acclimation is related to epigenitic regulation. Stress is related to only gene expression due to environment fluctuations.

Acclimation/acclimatization as well as adaptation are often used interchangeably in several studies and papers.

The first just denotes a physiological adjustment (often reversible, transient or ephemeral) of organisms (microbial communities decomposers for example) to changing environment ( increase soil temperature for example). Basically organisms in this case simply down-regulate their metabolism under sustained warming.

Adaptation on the other hand is seen as a kind of transformation, evolutionary and long term process through which a community instead of a single individual must undergo in order to cope to the changing environment.

One example of acclimation of soil respiration to increase soil temperature was observe at the Harvard forest (See Melillo et al. 2002, Science 298) where an increase of soil respiration in warmed plots observed during the first 6 years, became equivalent and even lower than soil respiration observed in the Control plots.

The acclimatization is the process by which the plant is exposed to different climatic or micro-climatic conditions such as gradual increase of temperature or clod stress treatment of seeds to become adapted.But acclimation is the natural process by which plants may survive in new climates and locations.

Acclimatization: it is the physiological , biochemical or anatomical modification occurring within the life time of an individual organism that result from chronic exposure to a naturally occurring environmental challenges. this means that acclimatization is a phenotypic changes only.

Acclimation: it is the physiological , biochemical or anatomical modification within an individual organism that result from exposure to an environmental challenges in a laboratory or field setting ( brought about by investigative manipulation. (phenotypic changes only).

Adaptation : it is the physiological , biochemical or anatomical modification occurring within a species that result from chronic exposure to a naturally occurring environmental challenges (over several generation) that facilitate an enhance ability to survive and reproduce in a particular environment . this means that adaptation is a genotypic change.

thanks a lot

Adaptation is the heritable modification in structure or function that increase fitness of the organism in stressful environment.

Acclimation is the non heritable physiological modification that occur over the life of an organism.

Acclimatization is the process in which an individual organism adjusts in stressful environment by allowing it to maintain performance across a range of environmental conditions.

Dear Mohemid Maddallah Al-Jebouri

Acclimation is defined as the coordinated phenotypic response developed by the animal to cope a specific stressor in the environment (e.g. hypoxia). This can be studied only in the laboratory when all the other environmental factors are controlled.

Acclimatization refers to a coordinated response to several simultaneous stressors (e.g., temperature, humidity, and photoperiod). This is most common in the natural environment where several factors change simultaneously affecting the subject under study

Adaptation involves permanent inherited characteristics (gene pool) as adverse environments persist over several generations of a population or species.

Thus, for instance, a trekker in the Himalayas requires a period of acclimatization to altitude, whereas a sherpa guide was born adapted to altitude.

Adaptation are changes that occur in organisms over a long period of time WHILE Acclimatization are changes that occur in organisms over a short period of time

Nafisat Mutohir you are describing acute versus chronic physiological responses. Adaptation only is reached by a population or species, after changes are integrated in the gene pool through natural or artificial selection. A subject born adapted or never can be adapted.

It will be critical to identify the mechanism by which acclimation/acclimatization will turn to adaptation (as a genetic trait). We might suggest that specific and global genome regulation (epigenetics/changes in DNA organisation (structural effects) will be involved. But is anyone aware that such a process was directly described/observed, is there any reference for it (in plant or animal/human research)?

Acclimation is the morphological and physiological adjustment by individual plants to compensate for the decline in performance following the initial stress response. Acclimation occurs in response to environmental change through changes in the activity or synthesis of new biochemical constituents such as enzymes, often associated with the production of new tissue. These biochemical changes then initiate a cascade of effects that we can observe at other levels, such as changes in rate or environmental sensitivity of a specific process (e.g., photosynthesis), growth rate of whole plants, and morphology of organs or the entire plant. Acclimation to stress always occurs within the lifetime of an individual, usually within days to weeks. Acclimation can be demonstrated by comparing genetically similar plants that are growing in different environments. The acclimation responses may be reversible (e.g., concentrations of compatible solutes in response to water stress), or irreversible (e.g., changes in the vascular system). None of these phenotypic changes involve any genotypic changes in the population.

Adaptation is the evolutionary response resulting from genetic changes in populations that compensate for the decline in performance caused by stress. The physiological mechanisms of response are often similar to those of acclimation, because both require changes in the activity or synthesis of biochemical constituents and cause changes in rates of individual physiological processes, growth rate, and morphology. In fact, adaptation may alter the potential of plants to acclimate to short-term environmental variation. Adaptation, as we define it, differs from acclimation in that it requires genetic changes in populations. It, therefore, typically requires many generations to occur. We can study adaptation by comparing genetically distinct plants grown in a common environment.

From "Lambers, H., & Oliveira, R. S. (2019). Introduction: History, Assumptions, and Approaches. In Plant Physiological Ecology (pp. 1-10). Springer, Cham."

Acclimatisation is one of the several ways by which human being adapt to the changing environment. Acclimatisation is more of a physiological way of adaptation. The other ways of adaptation are psychological (like expectation) or behavioural.

thanks a lot