In
evolution
Evolution is the change in the heritable Phenotypic trait, characteristics of biological populations over successive generations. It occurs when evolutionary processes such as natural selection and genetic drift act on genetic variation, re ...
, a maladaptation (
/ˌmælædæpˈteɪʃən/) is a
trait that is (or has become) more harmful than helpful, in contrast with an
adaptation
In biology, adaptation has three related meanings. Firstly, it is the dynamic evolutionary process of natural selection that fits organisms to their environment, enhancing their evolutionary fitness. Secondly, it is a state reached by the p ...
, which is more helpful than harmful. All organisms, from
bacteria
Bacteria (; : bacterium) are ubiquitous, mostly free-living organisms often consisting of one Cell (biology), biological cell. They constitute a large domain (biology), domain of Prokaryote, prokaryotic microorganisms. Typically a few micr ...
to
humans
Humans (''Homo sapiens'') or modern humans are the most common and widespread species of primate, and the last surviving species of the genus ''Homo''. They are Hominidae, great apes characterized by their Prehistory of nakedness and clothing ...
, display maladaptive and adaptive traits. Like adaptation, maladaptation may be viewed as occurring over geological time, or within the lifetime of one individual or a group.
Maladaptation can arise when adaptations to environmental challenges have unintended harmful effects by either decreasing the current
fitness of the organism or creating new risks which may decrease survivability. This could be caused by changes in trait distribution from genetic loading,
exogenous
In a variety of contexts, exogeny or exogeneity () is the fact of an action or object originating externally. It is the opposite of endogeneity or endogeny, the fact of being influenced from within a system.
Economics
In an economic model, an ...
environmental changes in the fitness landscape, or feedback in eco-plasticity, altering the fitness landscape.
It can also signify an adaptation that, whilst reasonable at the time, has become less and less suitable and more of a problem or hindrance in its own right, as time goes on. This is because it is possible for an adaptation to be poorly selected or become more of a dysfunction than a positive adaptation, over time.
Examples
Neuroplasticity
Neuroplasticity, also known as neural plasticity or just plasticity, is the ability of neural networks in the brain to change through neurogenesis, growth and reorganization. Neuroplasticity refers to the brain's ability to reorganize and rewir ...
is defined as "the brain's ability to reorganize itself by forming new neural connections throughout life". Neuroplasticity is seen as an adaptation that helps humans to adapt to new stimuli, especially through
motor functions
Motor control is the regulation of movements in organisms that possess a nervous system. Motor control includes conscious voluntary movements, subconscious muscle memory and involuntary reflexes, as well as instinctual taxes.
To control movem ...
in musically inclined people, as well as several other hand-eye coordination activities. An example of maladaptation in neuroplasticity within the evolution of the brain is
phantom pain
Phantom pain is a Pain, painful perception that an individual experiences relating to a Limb (anatomy), limb or an Organ (biology), organ that is not physically part of the body, either because it was amputation, removed or was never there in the ...
in individuals who have lost limbs. While the brain is exceptionally good at responding to stimuli and reorganizing itself in a new way to then later respond even better and faster in the future, it is sometimes unable to cope with the loss of a limb, even though the neurological connections are lost. According to the findings of one journal "Adaptation and Maladaptation" in some cases, the changes that had previously aided the human brain to best suit an environment could also become maladaptive.
[Nava, E., Roder, B., & Enhancing Performance for Action and Perception. (January 01, 2011). Adaptation and maladaptation. Progress in Brain Research, 191, 177–194.] In this case, with the loss of a limb, the brain is perceiving pain, though there are no nerves or signals from the now missing limb to give the brain that perception.
See also
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Black robin
The black robin or Chatham Island robin (Moriori language, Moriori: , ; ''Petroica traversi'') is an endangered bird from the Chatham Islands off the east coast of New Zealand. It is closely related to the South Island robin (''P. australis'') ...
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Ecological traps
Ecological traps are scenarios in which rapid environmental change leads organisms to prefer to settle in poor-quality habitats.
The concept stems from the idea that organisms that are actively selecting habitat must rely on environmental cues to h ...
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Evolutionary mismatch
Evolutionary mismatch (also "mismatch theory" or "evolutionary trap") is the evolutionary biology concept that a previously advantageous phenotypic trait, trait may become maladaptation, maladaptive due to change in the biophysical environment, e ...
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Maladaptive coping
Coping refers to conscious or unconscious strategies used to reduce and manage unpleasant emotions. Coping strategies can be cognitions or behaviors and can be individual or social. To cope is to deal with struggles and difficulties in life. It ...
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Evolutionary suicide
Evolutionary suicide is an evolutionary phenomenon in which the process of adaptation causes the population to become extinct. It provides an alternative explanation for extinction, which is due to misadaptation rather than failure to adapt.
For ...
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Fisherian runaway
Fisherian runaway or runaway selection is a sexual selection mechanism proposed by the mathematical biologist Ronald Fisher in the early 20th century, to account for the evolution of ostentatious male ornamentation by persistent, directional f ...
References
{{Authority control
Evolutionary biology
Selection