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For other uses, see Adaptation (disambiguation).
Part of the Biology series on
Evolution
Mechanisms and processes

Adaptation
Genetic drift
Gene flow
Mutation
Natural selection
Speciation
Research and history

Evidence
Evolutionary history of life
History
Modern synthesis
Social effect / Objections
Evolutionary biology fields

Cladistics
Ecological genetics
Evolutionary development
Human evolution
Molecular evolution
Phylogenetics
Population genetics
Biology Portal · v • d • e 

An adaptation is a positive characteristic of an organism that has been favored by natural selection and increases the fitness of its possessor. Foundations of modern biology There are five unifying principles eVolution is the third Album by eLDee, it was due to be released in 2008 In Population genetics, genetic drift is the accumulation of random events that change the makeup of a gene pool slightly but often compound over time In Population genetics, gene flow (also known as gene migration) is the transfer of Alleles of Genes from one Population to another In biology mutations are changes to the Nucleotide sequence of the Genetic material of an organism Natural selection is the process by which favorable Heritable traits become more common in successive Generations of a Population of Speciation is the Evolutionary process by which new biological Species arise The wide range of evidence of common descent of living things strongly indicates the occurrence of Evolution and provides a wealth of information on the natural processes Although evidence of early Life is scarce and often difficult to interpret it appears that life appeared on Earth relatively soon (on the Geologic time scale) after Evolutionary thought, the idea that species change over time has roots in antiquity in the ideas of the Greeks, Romans, Chinese and Muslims theory of transmutation had early origins in the speculations and hypotheses of Erasmus Darwin, and Jean-Baptiste Lamarck. Objections to evolution have been raised ever since various evolutionary ideas came to prominence around the start of the nineteenth century Cladistics is the hierarchical classification of Species based on evolutionary ancestry Ecological genetics is the study of Genetics in the context of the interactions among organisms and between the organisms and their environment Evolutionary developmental biology ( evolution of development or informally evo-devo) is a field of Biology that compares the developmental processes Human evolution, or anthropogenesis, is the part of biological Evolution concerning the emergence of Homo sapiens as a distinct Species Molecular evolution is the process of evolution at the scale of DNA, RNA, and Proteins Molecular evolution emerged as a scientific field in the 1960s as Population genetics is the study of the Allele frequency distribution and change under the influence of the four evolutionary forces Natural selection, Genetic Natural selection is the process by which favorable Heritable traits become more common in successive Generations of a Population of [1][2] Of course, an adaptation must have been adaptive at some point in an organism's evolutionary history, but such an organism's environment and ecological niche can change over time, leading to adaptations becoming redundant or even a hindrance (maladaptations). In Ecology, a niche (pronounced nich nēsh or nish A shorthand definition of niche is how an organism makes a living A maladaptation is an Adaptation that is (or has become more harmful than helpful Such adaptations are termed vestigial. Vestigiality describes homologous characters of Organisms which have lost all or most of their original function in a species through

Contents

Adaptation vs. acclimation

"Adaptation" is also sometimes used to refer to a change in an individual organism over the course of its life that makes it more suited to the environment. For an example, see Adaptation (eye). In ocular physiology adaptation is the ability of the Eye to adjust to various levels of darkness and light More specifically, however, such changes are referred to as acclimation or acclimatization, the former generally being a very short-term response such as shivering, the latter being a longer-term change such as sun tanning. Acclimatization is the process of an organism adjusting to chronic change in its environment, often involving temperature moisture food often relating to seasonal Climate Sun tanning describes a darkening of the skin (especially of fair-skinned individuals in a natural physiological response stimulated by exposure to ultraviolet (UV radiation [3]

There is a great difference between selective adaptation and acclimatization. Acclimatization is the process of an organism adjusting to chronic change in its environment, often involving temperature moisture food often relating to seasonal Climate Adaptation occurs over many generations; it is a gradual process caused by natural selection. Gradualism is the belief that changes occur or ought to occur slowly in the form of gradual steps (see also Incrementalism) Politics and society In Politics Acclimatization generally occurs within a single lifetime and copes with issues that are less threatening. For example, if a human was to move to a higher altitude, respiration and physical exertion would become a problem, but after spending time in high altitude conditions one may acclimate or acclimatize to the pressure and function and no longer notice the change. This ability to acclimate is an adaptation, but not the acclimatization itself.

A counter-adaptation is an adaptation that has evolved due to the selective pressure of another adaptation. This occurs in an evolutionary arms race, where a new adaptation giving one species an advantage is countered by the appearance and spread of a new feature that reduces the effectiveness of the first adaptation. In Evolutionary biology, an evolutionary arms race is an Evolutionary struggle between competing sets of co-evolving Genes that develop adaptations

Theories

Jean-Baptiste Lamarck
Jean-Baptiste Lamarck

The theory of adaptation was first put forth by Jean-Baptiste Lamarck. His theories are also referred to as the inheritance of acquired traits. inheritance of acquired characters (or characteristics) is the hereditary mechanism by which changes in physiology acquired over the life of an organism (such as muscle enlarged

Lamarck's theory was for a time held as an alternative scientific explanation for evolutionary change observed by Darwin in the The Origin of Species. Charles Robert Darwin (February 12 1809 &ndash April 19 1882 was an English naturalist, who realised and demonstrated that all Species of life Charles Darwin 's On the Origin of Species (published 24 November 1859) is a seminal work in Scientific literature and arguably the The classic giraffe analogy offers the best delineation between the two.

Although neither theory in its conception could provide a complete description of the mechanism of transmission of trait variation (i. e. , particulate inheritance), many recognized Darwin's theory immediately upon publication as a more complete and empirically supported theory. Modern genetics have since established the fundamental implausibility of Lamarckian inheritance, due to the one-way nature of transcription. However, see epigenetics and Baldwinian evolution for analogous processes in modern evolutionary. In Biology, the term epigenetics refers to changes in Gene expression caused by mechanisms other than changes in the underlying DNA sequence The Baldwin effect, also known as Baldwinian evolution or ontogenic evolution, is an early evolutionary Theory put forward in 1896 in a paper "A New

See also

References

  1. ^ Sterelny, K. An adaptive radiation is a rapid Evolutionary radiation characterized by an increase in the morphological and ecological diversity of a single rapidly diversifying lineage In Biology, co-adaptation, or coadaptation refers to the mutual adaptation of Species: see Mutualism, Symbiosis Exaptation, cooption, and preadaptation are related terms referring to shifts in the function of a trait during Evolution. Dual Inheritance Theory (DIT also known as Gene-Culture Coevolution, was developed in the late 1970s and early 1980s to explain how Human behavior is a product of The gene-centered view of evolution, gene selection theory or selfish gene theory holds that Natural selection acts through differential survival of competing See also Habit (psychology In Psychology, habituation is the psychological process in humans and animals in which there is a decrease in behavioral The Selfish gene theory postulates that Natural selection will increase the frequency of those genes whose phenotypic effects ensure their successful replication. Lamarckism (or Lamarckian evolution) is the once widely accepted idea that an organism can pass on characteristics that it acquired during its lifetime to its offspring (also The neutral theory of molecular evolution is an influential theory that was introduced with provocative effect by Motoo Kimura in the late 1960s and early 1970s In Evolutionary biology, preadaptation describes a situation where an organism uses a preexisting anatomical structure inherited from an ancestor for a potentially unrelated Spandrel is a term used in evolutionary biology describing a phenotypic characteristic that is considered to have developed during Evolution as a side-effect & Griffiths, P. E. (1999) Sex and Death: An Introduction to Philosophy of Biology p. 217 University of Chicago Press. ISBN O-226-77304-3
  2. ^ Freeman, S. & Herron, J. C. , (2007) "Evolutionary Analysis" p. 364 Pearson Education Inc. ISBN 0-13-227584-8 The concept is central to biology, particularly in evolutionary biology. Foundations of modern biology There are five unifying principles Evolutionary biology is a sub-field of Biology concerned with the origin of Species from a Common descent, and Descent of species The Oxford Dictionary of Science defines adaptation as "Something you have to get used to in the environment. Any change in the structure or functioning of an organism that makes it better suited to its environment is known as adaptation. " Adaptation is the change in living organisms that allow them to live successfully in an environment. Adaptations enable living organisms to cope with environmental stresses and pressures. Adaptations can be structural, behavioral or physiological. Structural adaptations are special body parts of an organism that help it to survive in its natural habitat (e. g. , skin colour, shape, body covering). Behavioural adaptations are special ways a particular organism behaves to survive in its natural habitat. Physiological adaptations are systems present in an organism that allow it to perform certain biochemical reactions (e. g. , making venom, secreting slime, being able to keep a constant body temperature). Adaptations are traits that have been selected by natural selection. The underlying genetic basis for the adaptive trait did not arise as a consequence of the environment; the genetic variant pre-existed and was subsequently selected because it provided the bearer of that variant some advantage. The first experimental evidence of the pre-existing nature of genetic variants was provided by Luria and Delbrück who developed fluctuation analysis, a method to show the random fluctuation of pre-existing genetic changes that conferred resistance to antibiotics by the bacterium Escherichia coli While many traits have obvious adaptive purposes, it is worthwhile to point out that many traits are not adaptive, that is, there is no obvious reason scientists can divine for the presence of a certain trait. This situation is common and there are many causes: the utility of a trait is lost and hence does not now appear adaptive, the utility of a trait is unknown, the trait is a consequence of another trait that is adaptive (the Spandrel idea). This observation underscores two other important points: genetic variants arise randomly and hence traits can appear randomly and that because the environment for all living things is constantly in flux, the utility of adaptations will naturally ebb and flow. Organisms that are not suitably adapted to their environment will either have to move out of the habitat or die out. The term die out in the context of adaptation simply means that the death rate over the entire species (population, gene pool . . . ) exceeds the birth rate for a long enough period for the species to disappear; due to individual phenotypic plasticity, individuals will be more or less successful. The ability of an organism with a given Genotype to change its Phenotype in response to changes in the environment is called phenotypic plasticity. The opposite is selection which in this context means that the birth rate of those carrying the adaptive trait and the hence the underlying genetic variant exceeds over time the birth rate of those that do not carry the adaptive trait.

    Adaptation vs. adaptiveness

    A trait being adaptive, i. e. increasing the organism's fitness, is neither a necessary nor sufficient condition for it to be an adaptation. Fitness (often denoted w in Population genetics models is a central concept in evolutionary theory. <ref>Sober, E. (1993) ''Philosophy of Biology''. p. 84 Boulder: Westview Press. </li>

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Dictionary

adaptation

-noun

  1. (uncountable) The quality of being adapted; adaption; adjustment.
  2. (uncountable) Adjustment to extant conditions: as, adjustment of a sense organ to the intensity or quality of stimulation; modification of some thing or its parts that makes it more fit for existence under the conditions of its current environment.
  3. (countable) Something which has been adapted; variation.
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