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Adaptation is the evolutionary process whereby a population becomes better suited to its habitat.[1][2] This process takes place over many generations,[3] and is one of the basic phenomena of biology.[4]

The term adaptation may also refer to a feature which is especially important for an organism's survival.[5] For example, the adaptation of horses' teeth to the grinding of grass, or their ability to run fast and escape predators. Such adaptations are produced in a variable population by the better suited forms reproducing more successfully, that is, by natural selection.

Contents

General principles

The significance of an adaptation can only be understood in relation to the total biology of the species. Julian Huxley [6]

Adaptation is, first of all, a process, rather than a physical part of a body.[7] The distinction may be seen in an internal parasite (such as a fluke), where the bodily structure is greatly simplified, but nevertheless the organism is highly adapted to its unusual environment. From this we see that adaptation is not just a matter of visible traits: in such parasites critical adaptations take place in the life-cycle, which is often quite complex.[8] However, as a practical term, adaptation is often used for the product: those features of a species which result from the process. Many aspects of an animal or plant can be correctly called adaptations, though there are always some features whose function is in doubt. By using the term adaptation for the evolutionary process, and adaptive trait for the bodily part or function (the product), the two senses of the word may be distinguished.

Adaptation may be seen as one aspect of a two-stage process. First, there is speciation (species-splitting or cladogenesis), caused by geographical isolation or some other mechanism.[9][10] Second, there follows adaptation, driven by natural selection. Something like this must have happened with Darwin's finches, and there are many other examples. The present favourite is the evolution of cichlid fish in African lakes, where the question of reproductive isolation is much more complex.[11][12]

Another great principle is that an organism must be viable at all stages of its development and at all stages of its evolution. This is obviously true, and it follows that there are constraints on the evolution of development, behaviour and structure of organisms. The main constraint, over which there has been much debate, is the requirement that changes in the system during evolution should be relatively small changes, because the body systems are so complex and interlinked. This is a sound principle, though there may be rare exceptions: polyploidy in plants is common,[13] and the symbiosis of micro-organisms that formed the eukaryota is a more exotic example.[14]

All adaptations help organisms survive in their ecological niches.[15] These adaptative traits may be structural, behavioral or physiological. Structural adaptations are physical features of an organism (shape, body covering, defensive or offensive armament); and also the internal organization). Behavioural adaptations are composed of inherited behaviour chains and/or the ability to learn: behaviours may be inherited in detail (instincts), or a tendency for learning may be inherited (see neuropsychology). Examples: searching for food, mating, vocalizations. Physiological adaptations permit the organism to perform special functions (for instance, making venom, secreting slime, phototropism); but also more general functions such as growth and development, temperature regulation, ionic balance and other aspects of homeostasis. Adaptation, then, affects all aspects of the life of an organism.

Definitions

The following definitions are mainly due to Theodosius Dobzhansky.

1. Adaptation is the evolutionary process whereby an organism becomes better able to live in its habitat or habitats.[16]
2. Adaptedness is the state of being adapted: the degree to which an organism is able to live and reproduce in a given set of habitats.[17]
3. An adaptive trait is an aspect of the developmental pattern of the organism which enables or enhances the probability of that organism surviving and reproducing.[18]

Adaptedness and fitness

From the above definitions, it is clear that there is a relationship between adaptedness and fitness (a key population genetics concept). Fitness is an estimate and a predictor of the rate of natural selection. What natural selection does is change the relative frequencies of alternative phenotypes, insofar as they are heritable.[19] Although the two are connected, the one does not imply the other: a phenotype with high adaptedness may not have high fitness. Dobzhansky mentioned the example of the Californian redwood, which is highly adapted, but a relic species in danger of extinction.[16] Elliott Sober commented that adaptation was a retrospective concept since it implied something about the history of a trait, whereas fitness predicts a trait's future.[20]

1. Fitness. The degree of demographic difference among phenotypes. Usually a relative measure: the average contribution to a breeding population by a phenotype or a class of phenotypes. This is also known as Darwinian fitness, relative fitness, selective coefficient, and other terms.
2. Adaptedness. Usually an absolute measure: the average absolute contribution to the breeding population by a carrier of a phenotype or a class of phenotypes. Also known as absolute fitness, and as the Malthusian parameter when applied to species as a whole.[21]

Brief history

Adaptation as a fact of life has been accepted by all the great thinkers who have tackled the world of living organisms. It is their explanations of how adaptation arises that separates these thinkers. A few of the most significant ideas:[22]

  • Empedocles did not believe that adaptation required a final cause (~ purpose), but "came about naturally, since such things survived". Aristotle, however, did believe in final causes.
  • In natural theology, adaptation was interpreted as the work of a deity, even as evidence for the existence of God.[23] William Paley believed that organisms were perfectly adapted to the lives they lead, an argument that shadowed Leibniz, who had argued that God had brought about the best of all possible worlds. Voltaire's Dr Pangloss[24] is a parody of this optimistic idea, and Hume also argued against design.[25] The Bridgewater Treatises are a product of natural theology, though some of the authors managed to present their work in a fairly neutral manner. The series was lampooned by Robert Knox, who held quasi-evolutionary views, as the Bilgewater Treatises. Darwin broke with the tradition by emphasising the flaws and limitations which occurred in the animal and plant worlds.[26]
Lamarck
  • Lamarck. His is a proto-evolutionary theory of the inheritance of acquired traits, whose main purpose is to explain adaptations by natural means.[27] He proposed a tendency for organisms to become more complex, moving up a ladder of progress, plus "the influence of circumstances", usually expressed as use and disuse. His evolutionary ideas, and those of Geoffroy, fail because they cannot be reconciled with heredity. This was known even before Mendel by medical men interested in human races (Wells, Lawrence), and especially by Weismann.

Many other students of natural history, such as Buffon, accepted adaptation, and some also accepted evolution, without voicing their opinions as to the mechanism. This illustrates the real merit of Darwin and Wallace, and secondary figures such as Bates, for pushing forward a mechanism whose significance had only been glimpsed previously. A century later, experimental field studies and breeding experiments by such as Ford and Dobzhansky produced evidence that natural selection was not only the 'engine' behind adaptation, but was a much stronger force than had previously been thought.[28][29][30]

Types of adaptation

Adaptation is the heart and soul of evolution. Niles Eldredge [31]

Changes in habitat

Before Darwin, adaptation was seen as a fixed relationship between an organism and its habitat. It was not appreciated that as the climate changed, so did the habitat; and as the habitat changed, so did the biota. Also, habitats are subject to changes in their biota: for example, invasions of species from other areas. The relative numbers of species in a given habitat are always changing. Change is the rule, though much depends on the speed and degree of the change.

When the habitat changes, three main things may happen to a resident population: habitat tracking, genetic change or extinction. In fact, all three things may occur in sequence. Of these three effects, only genetic change brings about adaptation.

Habitat tracking

When a habitat changes, the most common thing to happen is that the resident population moves to another locale which suits it; this is the typical response of flying insects or oceanic organisms, who have wide (though not unlimited) opportunity for movement.[32] This common response is called habitat tracking. It is one explanation put forward for the periods of apparent stasis in the fossil record (the punctuated equilibrium thesis).[33]

Genetic change

Genetic change is what occurs in a population when natural selection acts on the genetic variability of the population. By this means, the population adapts genetically to its circumstances.[34] Genetic changes may result in visible structures, or may adjust physiological activity in a way that suits the changed habitat.

It is now clear that habitats and biota do frequently change. Therefore, it follows that the process of adaptation is never finally complete.[35] Over time, it may happen that the environment changes little, and the species comes to fit its surroundings better and better. On the other hand, it may happen that changes in the environment occur relatively rapidly, and then the species becomes less and less well adapted. Seen like this, adaptation is a genetic tracking process, which goes on all the time to some extent, but especially when the population cannot or does not move to another, less hostile area. Also, to a greater or lesser extent, the process affects every species in a particular ecosystem.[36][37]

Van Valen thought that even in a stable environment, competing species had to constantly adapt to maintain their relative standing. This became known as the Red Queen hypothesis.

Intimate relationships: co-adaptations

In co-evolution, where the existence of one species is tightly bound up with the life of another species, new or 'improved' adaptations which occur in one species are often followed by the appearance and spread of corresponding features in the other species. There are many examples of this; the idea emphasises that the life and death of living things is intimately connected, not just with the physical environment, but with the life of other species. These relationships are intrinsically dynamic, and may continue on a trajectory for millions of years, as has the relationship between flowering plants and insects (pollination).

Pollinator constancy: these honeybees selectively visit flowers from only one species, as can be seen by the colour of the pollen in their baskets:

The gut contents, wing structures, and mouthpart morphologies of fossilized beetles and flies suggest that they acted as early pollinators. The association between beetles and angiosperms during the early Cretaceous period led to parallel radiations of angiosperms and insects into the late Cretaceous. The evolution of nectaries in late Cretaceous flowers signals the beginning of the mutualism between hymenopterans and angiosperms.[38]

Mimicry

A and B show real wasps; the rest are mimics: three hoverflies and one beetle.

Henry Walter Bates' work on Amazonian butterflies led him to develop the first scientific account of mimicry, especially the kind of mimicry which bears his name: Batesian mimicry.[39] This is the mimicry by a palatable species of an unpalatable or noxious species. A common example seen in temperate gardens is the hover-fly, many of which – though bearing no sting – mimic the warning colouration of hymenoptera (wasps and bees). Such mimicry does not need to be perfect to improve the survival of the palatable species.[40]

Bates, Wallace and Müller believed that Batesian and Müllerian mimicry provided evidence for the action of natural selection, a view which is now standard amongst biologists.[41] All aspects of this situation can be, and have been, the subject of research.[42] Field and experimental work on these ideas continues to this day; the topic connects strongly to speciation, genetics and development.[43]

The basic machinery: internal adaptations

There are some important adaptations to do with the overall coordination of the systems in the body. Such adaptations may have significant consequences. Examples, in vertebrates, would be temperature regulation, or improvements in brain function, or an effective immune system. An example in plants would be the development of the reproductive system in flowering plants.[44] Such adaptations may make the clade (monophyletic group) more viable in a wide range of habitats. The acquisition of such major adaptations has often served as the spark for adaptive radiation, and huge success for long periods of time for a whole group of animals or plants.

Compromise and conflict between adaptations

It is a profound truth that Nature does not know best; that genetical evolution... is a story of waste, makeshift, compromise and blunder. Peter Medawar [45]

All adaptations have a downside: horse legs are great for running on grass, but they can't scratch their backs; mammals' hair helps temperature, but offers a niche for ectoparasites; the only flying penguins do is under water. Adaptations serving different functions may be mutually destructive. Compromise and make-shift occur widely, not perfection. Selection pressures pull in different directions, and the adaptation that results is some kind of compromise.[46]

Since the phenotype as a whole is the target of selection, it is impossible to improve simultaneously all aspects of the phenotype to the same degree. Ernst Mayr [47]

Consider the antlers of the Irish elk, (often supposed to be far too large; in deer antler size has an allometric relationship to body size). Obviously antlers serve positively for defence against predators, and to score victories in the annual rut. But they are costly in terms of resource. Their size during the last glacial period presumably depended on the relative gain and loss of reproductive capacity in the population of elks during that time.[48] Another example: camouflage to avoid detection is destroyed when vivid colors are displayed at mating time. Here the risk to life is counterbalanced by the necessity for reproduction.

An Indian Peacock's train
in full display

The peacock's ornamental train (grown anew in time for each mating season) is a famous adaptation. It must reduce his maneuverability and flight, and is hugely conspicuous; also, its growth costs food resources. Darwin's explanation of its advantage was in terms of sexual selection: "it depends on the advantage which certain individuals have over other individuals of the same sex and species, in exclusive relation to reproduction." [49] The kind of sexual selection represented by the peacock is called 'mate choice', with an implication that the process selects the more fit over the less fit, and so has survival value.[50] The recognition of sexual selection was for a long time in abeyance, but has been rehabilitated.[51] In practice, the blue peafowl Pavo cristatus is a pretty successful species, with a big natural range in India, so the overall outcome of their mating system is quite viable.

The conflict between the size of the human foetal brain at birth, (which cannot be larger than about 400ccs, else it will not get through the mother's pelvis) and the size needed for an adult brain (about 1400ccs), means the brain of a newborn child is quite immature. The most vital things in human life (locomotion, speech) just have to wait while the brain grows and matures. That is the result of the birth compromise. Much of the problem comes from our upright bipedal stance, without which our pelvis could be shaped more suitably for birth. Neanderthals had a similar problem.[52][53][54]

Shifts in function

Adaptation and function are two aspects of one problem. Julian Huxley [55]

Pre-adaptations

This occurs when a species or population has characteristics which (by chance) are suited for conditions which have not yet arisen. For example, the polyploid rice-grass Spartina townsendii is better adapted than either of its parent species to their own habitat of saline marsh and mud-flats.[56] White Leghorn fowl are markedly more resistant to vitamin B deficiency than other breeds.[57] On a plentiful diet there is no difference, but on a restricted diet this preadaptation could be decisive.

Pre-adaptation may occur because a natural population carries a huge quantity of genetic variability.[58] In diploid eukaryotes, this is a consequence of the system of sexual reproduction, where mutant alleles get partially shielded, for example, by the selective advantage of heterozygotes. Micro-organisms, with their huge populations, also carry a great deal of genetic variability.

The first experimental evidence of the pre-adaptive nature of genetic variants in micro-organisms was provided by Salvador Luria and Max Delbrück who developed fluctuation analysis, a method to show the random fluctuation of pre-existing genetic changes that conferred resistance to phage in the bacterium Escherichia coli.

Co-option of existing traits: exaptation

The classic example is the ear ossicles of mammals, which we know from palaeontological and embrological studies originated in the upper and lower jaws and the hyoid of their Synapsid ancestors, and further back still were part of the gill arches of early fish.[59][60] We owe this esoteric knowledge to the comparative anatomists, who, a century ago, were at the cutting edge of evolutionary studies.[61] The word exaptation was coined to cover these shifts in function, which are surprisingly common in evolutionary history.[62] The origin of wings from feathers that were originally used for temperature regulation is a more recent discovery (see feathered dinosaurs).

Related issues

Non-adaptive traits

Some traits appear to be not adaptive, that is, selectively neutral. There may be various causes: the utility of a trait is lost and does not now appear adaptive; the utility of a trait is unknown; the trait is a consequence of another trait that is adaptive (i.e. spandrels). Because genes have pleiotropic effects, not all traits may be functional. Of course, a trait may have been adaptive at some point in an organism's evolutionary history, but habitats change, leading to adaptations becoming redundant or even a hindrance (maladaptations). Such adaptations are termed vestigial. So, the utility of adaptations may ebb and flow.

Fitness landscapes; drift

Sewall Wright's explanation for evolutionary stasis was that organisms come to occupy adaptive peaks. In order to evolve to another, higher peak, the species would first have to pass through a valley of maladaptive intermediate stages. This could happen by genetic drift if the population were small enough. This was Wright's shifting balance theory of evolution.[63] There has been much skepticism among evolutionary biologists as to whether these rather delicate conditions hold often in natural populations.[58] Ronald Fisher felt that most populations in nature were too large for these effects of genetic drift to be important.[28]

Vestigial organs

Many organisms have vestigial organs, which are the remnants of fully functional structures in their ancestors. As a result of changes in lifestyle the organs became redundant, and are either not functional or reduced in functionality. With the loss of function goes the loss of positive selection, and the subsequent accumulation of deleterious mutations. Since any structure represents some kind of cost to the general economy of the body, an advantage may accrue from their elimination once they are not functional. Examples: wisdom teeth in humans; the loss of pigment and functional eyes in cave fauna; the loss of structure in endoparasites.[64]

Extinction

If a population cannot move or change sufficiently to preserve its long-term viability, then obviously, it will become extinct, at least in that locale. The species may or may not survive in other locales. Species extinction occurs when the death rate over the entire species (population, gene pool ...) exceeds the birth rate for a long enough period for the species to disappear. It was an observation of Van Valen that groups of species tend to have a characteristic and fairly regular rate of extinction.[65]

Co-extinction

Just as we have co-adaptation, there is also co-extinction. Co-extinction refers to the loss of a species due to the extinction of another; for example, the extinction of parasitic insects following the loss of their hosts. Co-extinction can also occur when a flowering plant loses its pollinator, or through the disruption of a food chain.[66] "Species co-extinction is a manifestation of the interconnectedness of organisms in complex ecosystems ... While co-extinction may not be the most important cause of species extinctions, it is certainly an insidious one".[67]

Flexibility, acclimatization, learning

Flexibility deals with the relative capacity of an organism to maintain themselves in different habitats: their degree of specialization. Acclimatization is a term used for automatic physiological adjustments during life; learning is the term used for improvement in behavioral performance during life. In biology these terms are preferred, not adaptation, for changes during life which improve the performance of individuals. These adjustments are not inherited genetically by the next generation.

Adaptation, on the other hand, occurs over many generations; it is a gradual process caused by natural selection which changes the genetic make-up of a population so the collective performs better in its niche.

Flexibility

Populations differ in their phenotypic plasticity, which is the ability of an organism with a given genotype to change its phenotype in response to changes in its habitat, or to its move to a different habitat.[68][69]

To a greater or lesser extent, all living things can adjust to circumstances. The degree of flexibility is inherited, and varies to some extent between individuals. A highly specialized animal or plant lives only in a well-defined habitat, eats a specific type of food, and cannot survive if its needs are not met. Many herbivores are like this; extreme examples are koalas which depend on eucalyptus, and pandas which require bamboo. A generalist, on the other hand, eats a range of food, and can survive in many different conditions. Examples are humans, rats, crabs and many carnivores. The tendency to behave in a specialized or exploratory manner is inherited – it is an adaptation.

Rather different is developmental flexibility: "An animal or plant is developmentally flexible if when it is raised or transferred to new conditions it develops so that it is better fitted to survive in the new circumstances".[70] Once again, there are huge differences between species, and the capacities to be flexible are inherited.

Acclimatization

If humans move to a higher altitude, respiration and physical exertion become a problem, but after spending time in high altitude conditions they acclimatize to the pressure by increasing production of red blood corpuscles. The ability to acclimatize is an adaptation, but not the acclimatization itself. Fecundity goes down, but deaths from some tropical diseases also goes down.

Over a longer period of time, some people will reproduce better at these high altitudes than others. They will contribute more heavily to later generations. Gradually the whole population becomes adapted to the new conditions. This we know takes place, because the performance of long-term communities at higher altitude is significantly better than the performance of new arrivals, even when the new arrivals have had time to make physiological adjustments.[71]

Some kinds of acclimatization happen so rapidly that they are better called reflexes. The rapid colour changes in some flatfish, cephalopods, chameleons are examples.[72]

Learning

Social learning is supreme for humans, and is possible for quite a few mammals and birds: of course, that does not involve genetic transmission except to the extent that the capacities are inherited. Similarly, the capacity to learn is an inherited adaptation, but not what is learnt; the capacity for human speech is inherited, but not the details of language.

Function and teleonomy

Adaptation raises some issues concerning how biologists use key terms such as function.

Function

To say something has a function is to say something about what it does for the organism, obviously. It also says something about its history: how it has come about. A heart pumps blood: that is its function. It also emits sound, which is just an ancillary side-effect. That is not its function. The heart has a history (which may be well or poorly understood), and that history is about how natural selection formed and maintained the heart as a pump. Every aspect of an organism that has a function has a history. Now, an adaptation must have a functional history: therefore we expect it must have undergone selection caused by relative survival in its habitat. It would be quite wrong to use the word adaptation about a trait which arose as a by-product.[73][74]

It is widely regarded as unprofessional for a biologist to say something like "A wing is for flying", although that is their normal function. A biologist would be conscious that sometime in the remote past feathers on a small dinosaur had the function of retaining heat, and that later many wings were not used for flying (e.g. penguins, ostriches). So, the biologist would rather say that the wings on a bird or an insect usually had the function of aiding flight. That would carry the connotation of being an adaptation with a history of evolution by natural selection.

Teleonomy

Teleonomy is a term invented to describe the study of goal-directed functions which are not guided by the conscious forethought of man or any supernatural entity. It is contrasted with Aristotle's teleology, which has connotations of intention, purpose and foresight. Evolution is teleonomic; adaptation hoards hindsight rather than foresight. The following is a definition for its use in biology:

Teleonomy: The hypothesis that adaptations arise without the existence of a prior purpose, but by the action of natural selection on genetic variability.[75]

The term may have been suggested by Colin Pittendrigh in 1958;[76] it grew out of cybernetics and self-organising systems. Ernst Mayr, George C. Williams and Jacques Monod picked up the term and used it in evolutionary biology.[77][78][79][80]

Philosophers of science have also commented on the term. Ernest Nagel analysed the concept of goal-directedness in biology;[81] and David Hull commented on the use of teleology and teleonomy by biologists:

Haldane can be found remarking, "Teleology is like a mistress to a biologist: he cannot live without her but he’s unwilling to be seen with her in public." Today the mistress has become a lawfully wedded wife. Biologists no longer feel obligated to apologize for their use of teleological language; they flaunt it. The only concession which they make to its disreputable past is to rename it ‘teleonomy’.[82]

References

  1. ^ The Oxford Dictionary of Science defines adaptation as "Any change in the structure or functioning of an organism that makes it better suited to its environment".
  2. ^ Bowler P.J. 2003. Evolution: the history of an idea. California. p10
  3. ^ Patterson C. 1999. Evolution. Natural History Museum, London. p1
  4. ^ Williams, George C. 1966. Adaptation and natural selection: a critique of some current evolutionary thought. Princeton. "Evolutionary adaptation is a phenomenon of pervasive importance in biology." p5
  5. ^ Both uses of the term 'adaptation' are recognized by King R.C. Stansfield W.D. and Mulligan P. 2006. A dictionary of genetics. Oxford, 7th ed.
  6. ^ Huxley, Julian 1942. Evolution the modern synthesis. Allen & Unwin, London. p449
  7. ^ Mayr, Ernst 1982. The growth of biological thought. Harvard. p483: "Adaptation... could no longer be considered a static condition, a product of a creative past, and became instead a continuing dynamic process."
  8. ^ Price P.W. 1980. The evolutionary biology of parasites. Princeton.
  9. ^ Mayr E. 1963. Animal species and evolution. Harvard.
  10. ^ Mayr, Ernst 1982. The growth of biological thought: diversity, evolution and inheritance. Harvard. p562–566
  11. ^ Salzburger W., Mack T., Verheyen E., Meyer A. (2005). "Out of Tanganyika: Genesis, explosive speciation, key-innovations and phylogeography of the haplochromine cichlid fishes" (PDF). BMC Evolutionary Biology 5 (17): 17. doi:10.1186/1471-2148-5-17. http://www.biomedcentral.com/content/pdf/1471-2148-5-17.pdf. 
  12. ^ Kornfield, Irv; Smith, Peter (November 2000). "African Cichlid Fishes: Model Systems for Evolutionary Biology". Annual Review of Ecology and Systematics 31: 163. doi:10.1146/annurev.ecolsys.31.1.163. http://arjournals.annualreviews.org/doi/abs/10.1146/annurev.ecolsys.31.1.163. 
  13. ^ Stebbins, G. Ledyard, Jr. 1950. Variation and evolution in plants. Columbia. Polyploidy, chapters 8 and 9.
  14. ^ Margulis, Lynn (ed) 1991. Symbiosis as a source of evolutionary innovation: speciation and morphogenesis MIT. ISBN 0-262-13269-9
  15. ^ Hutchinson G. Evelyn 1965. The ecological theatre and the evolutionary play. Yale. The niche is the central concept in evolutionary ecology; see especially part II The niche: an abstractly inhabited hypervolume. p26–78
  16. ^ a b Dobzhansky T. 1968. On some fundamental concepts of evolutionary biology. Evolutionary biology 2, 1–34.
  17. ^ Dobzhansky T. 1970. Genetics of the evolutionary process. Columbia, N.Y. p4–6, 79–82, 84–87
  18. ^ Dobzhansky T. 1956. Genetics of natural populations XXV. Genetic changes in populations of Drosophila pseudoobscura and Drosphila persimilis in some locations in California. Evolution 10, 82–92.
  19. ^ Endler, John A. 1986. Natural selection in the wild. Princeton. p33–51: 'Fitness and adaptation'.
  20. ^ Sober, Elliott 1984. The nature of selection: a philosophical enquiry. M.I.T.
  21. ^ following discussion in Endler, John A. 1986. Natural selection in the wild. Princeton. p33–51: 'Fitness and adaptation'.
  22. ^ references and details in their articles
  23. ^ Desmond, Adrian 1989. The politics of evolution. Chicago. p31/32, footnote 18.
  24. ^ in Candide, ou l'optimisme
  25. ^ Sober, Elliott 1993. Philosophy of biology. Oxford. Chapter 2
  26. ^ Darwin, Charles. 1872. The origin of species. 6th edition, p397: Rudimentary, atrophied and aborted organs.
  27. ^ see, for example, the discussion in Bowler, Peter H. 2003. Evolution: the history of an idea. 3rd ed, California. p86–95, especially "Whatever the true nature od Lamark's theory, it was his mechanism of adaptation that caught the attention of later naturalists". (p90)
  28. ^ a b Provine, William 1986. Sewall Wright and evolutionary biology. University of Chicago Press.
  29. ^ Ford E.B. 1975. Ecological genetics, 4th ed. Chapman and Hall, London.
  30. ^ Orr H. 2005. The genetic theory of adaptation: a brief history. Nature Rev. Genetics 6, 2, p119–127.
  31. ^ Eldredge, Niles 1995. Reinventing Darwin: the great evolutionary debate. Wiley N.Y. p33
  32. ^ Eldredge, Niles 1986. Time frames: the rethinking of Darwinian evolution and the theory of punctuated equilibria. p136, Of glaciers and beetles.
  33. ^ Eldredge, Niles 1995. Reinventing Darwin: the great evolutionary debate. Wiley, N.Y. p64
  34. ^ Orr H. 2005. The genetic theory of adaptation: a brief history. Nature Rev. Genetics, 6, 119–127.
  35. ^ Mayr, Ernst 1982. The growth of biological thought: diversity, evolution and inheritance. Harvard. Harvard. p481 (and sequence) tells how Darwin's ideas on adaptation developed as he came to appreciate it as "a continuing dynamic process" (bottom p483).
  36. ^ Sterelny K. & Griffiths P.E. 1999. Sex and death: an introduction to philosophy of biology. University of Chicago Press. p217 ISBN O-226-77304-3
  37. ^ Freeman S. & Herron J.C. 2007. Evolutionary analysis. Pearson Education. p364 ISBN 0-13-227584-8
  38. ^ Stebbins, G. Ledyard, Jr. 1974. Flowering plants: evolution above the species level. Harvard.
  39. ^ Carpenter GDH and Ford EB 1933. Mimicry. Methuen, London.
  40. ^ Wickler W. 1968. Mimicry in plants and animals. World University Library, London.
  41. ^ Moon H.P. 1976. Henry Walter Bates FRS 1825-1892: explorer, scientist and darwinian. Leicestershire Museums, Leicester.
  42. ^ Ruxton GD, Sherratt TN and Speed MP 2004. Avoiding attack: the evolutionary ecology of crypsis, warning signals and mimicry. Oxford.
  43. ^ Mallet, James 2001. The speciation revolution. J Evolutionary Biology 14, 887-8.
  44. ^ Stebbins, G. Ledyard, Jr. 1974. Flowering plants: evolution above the species level. Harvard. Contains an extensive analysis of the evolution of adaptations in the radiation of Angiosperms.
  45. ^ Medawar, Peter 1960. The future of Man. Methuen, London.
  46. ^ Jacob, Francois 1977. Evolution and tinkering. Science 196 1161–1166.
  47. ^ Mayr, Ernst 1982. The growth of biological thought: diversity, evolution and inheritance. Harvard. p589
  48. ^ It is, of course, not possible to test selective pressures on extinct populations in any direct way. Gould, Stephen J. (1974): Origin and function of 'bizarre' structures - antler size and skull size in 'Irish Elk', Megaloceros giganteus. Evolution 28(2): 191-220. doi:10.2307/2407322 (First page text)
  49. ^ Darwin, Charles 1871. The Descent of Man and selection in relation to sex. Murray, London.
  50. ^ The case was treated by Fisher R.A. 1930. Genetical theory of natural selection. Oxford. p134–139.
  51. ^ Cronin, Helen 1991. The ant and the peacock: altruism and sexual selection from Darwin to the present day. Cambridge.
  52. ^ Rosenberg K.R. 2005. The evolution of modern human childbirth. Am J. Physical Anthropology 35, p89–124.
  53. ^ Friedlander, Nancy & Jordan, David K. 1995. Obstetric implications of Neanderthal robusticity and bone density. Human Evolution (Florence) 9: 331-342.
  54. ^ Miller, Geoffrey 2007. Brain evolution. In Gangestad S.W. and Simpson J.A. (eds) The evolution of mind: fundamental questions and controversies. Guildford.
  55. ^ Huxley, Julian 1942. Evolution the modern synthesis. Allen & Unwin, London. p417
  56. ^ Huskins C.L. 1931. The origin of Spartina townsendii. Genetica 12, 531.
  57. ^ Lamoreux W.F and Hutt F.B. 1939. Breed differences in resistance to a deficiency in vitamin B1 in the fowl. J. Agric. Res. Washington 58, 307–315.
  58. ^ a b [Dobzhansky T.] 1981. Dobzhansky's genetics of natural populations. eds Lewontin RC, Moore JA, Provine WB and Wallace B. Columbia University Press N.Y.
  59. ^ Egdar F. Allin and James A. Hopson 1992. Evolution of the auditory system in Synapsida ("Mammal-like reptiles" and primitive mammals) as seen in the fossil record. Section IV (Mammals), Chapter 28, pages 587-614 in The evolutionary biology of hearing edited by Douglas B. Webster, Richard R. Fay, and Arthur N. Popper. Springer-Verlag. ISBN 0-387-97588-8.
  60. ^ Neil Shubin 2008. Your Inner Fish: a journey into the 3.5-billion-year history of the human body Pantheon Books 2008. ISBN 978-0-375-42447-2. Chapter 10, "Ears"
  61. ^ Panchen, Alec. 1992. Classification, evolution and the nature of biology. Cambridge. Chapter 4 Homology and the evidence for evolution.
  62. ^ Gould, Stephen Jay and Elizabeth S. Vrba 1982. Exaptation – a missing term in the science of form. Paleobiology 8, 1, 4–15.
  63. ^ Wright, Sewall 1932. The roles of mutation, inbreeding, crossbreeding, and selection in evolution. In Proceedings of the Sixth International Congress on Genetics, p355–366.
  64. ^ Charles Darwin was the first to put forward such ideas: Barrett P.H. (ed) 1987. Charles Darwin's notebooks (1836–1844). Cambridge.
  65. ^ Van Valen L. 1973. A new evolutionary law. Evolutionary Theory 1, 1–30.
  66. ^ Darwin in the Origin of Species tells the story of "a web of complex relations" involving heartsease (Viola tricolor), red clover (Trifolium pratense, humble-bees (bumblebees), mice and cats. Origin, 6th edition, p57.
  67. ^ Koh, Lian Pih. 2004. Science, 305, 5690, 1632-1634, 10 September 2004.
  68. ^ Price TD, Qvarnström A & Irwin DE 2003. The role of phenotypic plasticity in driving genetic evolution. Proc. Biol. Sci. 270 p1433–1440.
  69. ^ Price T.D. 2006. Phenotypic plasticity, sexual selection and the evolution of colour patterns. J Exp Biol. 209 p2368–2376
  70. ^ Maynard Smith J. 1993. The theory of evolution. Cambridge. 3rd ed, p33.
  71. ^ Moore Lorna G. and Regensteiner Judith G. 1983. Adaptation to high altitude. Ann. Rev. Anthropology 12, p285–304.
  72. ^ Maynard Smith uses the term physiologically versatile for such animals. Maynard Smith J. 1993. The theory of evolution. Cambridge. 3rd ed, p32.
  73. ^ Sober, Elliott 1993. Philosophy of biology. Oxford. p85–86
  74. ^ Williams, George C. 1966. Adaptation and natural selection: a critique of some current evolutionary thought. Princeton. p8–10
  75. ^ "The hypothesis that adaptations arise without the existence of a prior purpose, but by chance may change the fitness of an organism." Oxford Dictionary of Zoology. But one might question the word chance, since natural selection, by its operation in particular habitats, is not a random process (it may be a stochastic or probabilistic process, however).
  76. ^ Pittendrigh C.S. 1958. Adaptation, natural selection and behavior. In A. Roe and George Gaylord Simpson (eds) Behavior and evolution. Yale.
  77. ^ Mayr, Ernst 1965. Cause and effect in biology. In D. Lerner (ed) Cause and effect. Free Press, New York. p33–50.
  78. ^ Mayr, Ernst 1988. Toward a new philosophy of biology. Chapter 3 "The multiple meanings of teleological".
  79. ^ Williams, George C. 1966. Adaptation and natural selection; a critique of some current evolutionary thought. Chapter 9. Princeton.
  80. ^ Monod, Jacques 1971. Chance and necessity: an essay on the natural philosophy of modern biology. Knopf, New York. ISBN 0-394-46615-2
  81. ^ Nagel, E. 1977. Teleology revisited: goal-directed processes in biology. Journal of Philosophy 74: 261–301.
  82. ^ Hull D.L. 1982. Philosophy and biology. In G. Fløistad (ed) Philosophy of Science Nijhoff.

See also


Quotes

Up to date as of January 14, 2010
(Redirected to Adaptation. article)

From Wikiquote

Adaptation. is a 2002 film about a screenwriter who, having trouble adapting a non-fiction novel to the big screen, asks for the assistance of his less experienced twin brother.

Directed by Spike Jonze. Written by Susan Orlean (book) and Charlie Kaufman (screenplay).

Contents

Charlie Kaufman

  • To begin... To begin... How to start? I'm hungry. I should get coffee. Coffee would help me think. Maybe I should write something first, then reward myself with coffee. Coffee and a muffin. So I need to establish the themes. Maybe a banana nut. That's a good muffin.
  • I don't want to cram in sex or guns or car chases or characters learning profound life lessons or growing or coming to like each other or overcome obstacles to succeed in the end. The book isn't like that, and life isn't like that, it just isn't.
  • [voiceover] I should have gone in. I'm such a chicken. I should have kissed her. I should go knock on her door and just kiss her. It would be romantic. It would be something we'd tell our kids about someday. I'm going to do that right now. [drives away]
  • You and I share the same DNA. Is there anything more lonely than that?
  • I'd wanna let the movie exist, rather than be artificially plot-driven.
  • [voiceover] Do I have an original thought in my head? My bald head. Maybe if I were happier my hair wouldn't be falling out. Life is short. I need to make the most of it. Today is the first day of the rest of my life. I'm a walking cliché. I really need to go to the doctor and have my leg checked. There's something wrong. A bump. The dentist called again. I'm way overdue. If I stop putting things off I would be happier. All I do is sit on my fat ass. If my ass wasn't fat I would be happier. I wouldn't have to wear these shirts with the tails out all the time. Like that's fooling anyone. Fat ass. I should start jogging again. Five miles a day. Really do it this time. Maybe rock climbing. I need to turn my life around. What do I need to do? I need to fall in love. I need to have a girlfriend. I need to read more. Improve myself. What if I learned Russian or something, or took up an instrument. I could speak Chinese. I'd be the screenwriter who speaks Chinese and plays the oboe. That would be cool. I should get my hair cut short. Stop trying to fool myself and everyone else into thinking I have a full head of hair. How pathetic is that. Just be real. Confident. Isn't that what women are attracted to? Men don't have to be attractive. But that's not true. Especially these days. Almost as much pressure on men as there is on women these days. Why should I be made to feel I have to apologize for my existence? Maybe it's my brain chemistry. Maybe that's what's wrong with me. Bad chemistry. All my problems and anxiety can be reduced to a chemical imbalance or some kind of misfiring synapses. I need to get help for that. But I'll still be ugly though. Nothing's going to change that.
  • What the hell do you need binoculars for?!

Donald Kaufman

  • You are what you love, not what loves you, I decided that a long time ago.
  • [delighted] I got shot. Isn't that fucked up?
  • McKee says we all have to realize we write in a genre, so we must find originality within that genre. Did you know that there hasn't been a new genre since Fellini invented the mockumentary...? My genre's thriller, what's yours?
  • [reads] Sometimes this kind of story turns out to be something more, some glimpse of life that expands like those japanese paper balls you drop in water and the bloom into flowers and the flower is so marvelous you can't believe there was a time all you saw in front of you was a paper ball and a glass of water.

John Laroche

  • Who's gonna play me? I think I should play me.
  • I'm probably the smartest person I know.
  • By simply doing what they are designed to do something large and magnificient happens. In this sense they show us how to live. How the only barometer you have is your heart. How when you spot your flower, you can't let anything get in your way.
  • Darkness descends, bad things happen.

Susan Orlean

  • I suppose I do have one unembarrassed passion. I want to know how it feels like to care about something passionately.
  • There are too many ideas and things and people. Too many directions to go. I was starting to believe the reason it matters to care passionately about something is that it whittles the world down to a more managable size.
  • Most people yearn for something exceptional, something so inspiring that they'd want to risk everything for that passion, but few would act on it. It was very powerful and intoxicating to be around someone so alive.
  • It's over. Everything, I did everything wrong. I want my life back. I want it back before everything got fucked up. I want to be a baby again. I want to be new. I want to be new.
  • Change is not a choice. Not for a species of plant, and not for me.

Robert McKee

  • I'll tell you a secret. The last act makes the film. Wow them in the end, and you've got a hit. You can have flaws, problems, but wow them in the end, and you've got a hit. Find an ending, but don't cheat, and don't you dare bring in a deus ex machina. Your characters must change, and the change must come from them. Do that, and you'll be fine.

Amelia Kavan

  • I love you too, you know.

Dialogue

Charlie Kaufman: The script I'm starting, it's about flowers. No one's ever done a movie about flowers before. So there are no guidelines...
Donald Kaufman: What about "Flowers for Algernon"?
Charlie Kaufman: Well, that's not about flowers. And it's not a movie.
Donald Kaufman: Ok, I'm sorry, I never saw it.

Donald Kaufman: Listen, I need a cool way to kill people. Don't worry, for my script.
Charlie Kaufman: I don't know that kind of stuff.
Donald Kaufman: Oh, come on, man, please? You're the genius.
Charlie Kaufman: Here you go. The killer's a literature professor. He cuts off little chunks from his victims' bodies until they die. He calls himself "the deconstructionist".

Donald Kaufman: I'm putting in a chase sequence. So the killer flees on horseback with the girl, the cop's after them on a motorcycle and it's like a battle between motors and horses, like technology vs. horse.
Charlie Kaufman: And they're still all one person, right?

Charlie Kaufman: [voiceover] I'm pathetic, I'm a loser. I have failed, I am panicked. I've sold out, I am worthless, I... What the fuck am I doing here? What the fuck am I doing here? Fuck. It is my weakness, my ultimate lack of conviction that brings me here. Easy answers used to shortcut yourself to success. And here I am because my jump into the abysmal well - isn't that just a risk one takes when attempting something new? I should leave here right now. I'll start over. I need to face this project head on and...
Robert McKee:...and God help you if you use voice-over in your work, my friends. God help you. That's flaccid, sloppy writing. Any idiot can write a voice-over narration to explain the thoughts of a character.

Donald Kaufman: I'm pitching my script today.
Charlie Kaufman: Please don't say pitch.

[At a seminar, Charlie Kaufman has asked McKee for advice on his new screenplay in which 'nothing much happens']
Robert McKee: Nothing happens in the world? Are you out of your fucking mind? People are murdered every day. There's genocide, war, corruption. Every fucking day, somewhere in the world, somebody sacrifices his life to save someone else. Every fucking day, someone, somewhere makes a conscious decision to destroy someone else. People find love, people lose it. For Christ's sake, a child watches her mother beaten to death on the steps of a church. Someone goes hungry. Somebody else betrays his best friend for a woman. If you can't find that stuff in life, then you, my friend, don't know crap about life. And why the FUCK are you wasting my two precious hours with your movie? I don't have any use for it. I don't have any bloody use for it.
Charlie Kaufman: Ok, thank you.

John Laroche: Then one morning, I woke up and said, "Fuck fish." I renounce fish, I will never set foot in that ocean again. And there hasn't been a time where I have stuck so much as a toe back in that ocean.
Susan Orlean: But why?
John Laroche: Done with fish.

John Laroche: You know why I like plants?
Susan Orlean: Nuh uh.
John Laroche: Because they're so mutable. Adaptation is a profound process. Means you figure out how to thrive in the world.
Susan Orlean: [pause] Yeah but it's easier for plants. I mean they have no memory. They just move on to whatever's next. With a person though, adapting almost shameful. It's like running away.

John Laroche: Darling, I don't know what's come over you.
Susan Orlean: You came all over me.
John Laroche: My goodness.

Charlie Kaufman: Mr. McKee! I'm the guy you yelled at today.
Robert McKee: I need more.

Charlie Kaufman: ...But a little fantastic and fleeting and out of reach.
Robert McKee: Then what happens?
Charlie Kaufman: That's the end of the book. I wanted to present it simply without big character arcs or sensationalizing the story. I wanted to show flowers as God's miracles. I wanted to show that Orlean never saw the blooming ghost orchid. It was about disappointment.

External links

Wikipedia
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1911 encyclopedia

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From LoveToKnow 1911

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Simple English

Adaptation is the evolutionary process whereby an organism becomes better suited to its habitat.[1][2] This process takes place over many generations.[3] It is one of the basic phenomena of biology.[4]

When people speak about adaptation, they often mean a feature (a trait) which helps an animal or plant survive. An example is the adaptation of horses' teeth to grinding grass. Grass is their usual food; it wears the teeth down, but horses' teeth continue to grow during life. Horses also have adapted to run fast, which helps them to escape their predators, such as lions. These features are the product of the process of adaptation.

The better adapted animals are the most likely to survive, and to reproduce successfully. This process is known as natural selection; it is the basic cause of evolutionary change.

Some traits are heritable, but appear to be neutral or even disadvantageous to the organism. There are at least two possibilities:

1. They may be the pleiotropic effects of genes which have been selected for other, beneficial, traits.
2. They may be produced by a balance between selection for general survival, and selection for successful reproduction (sexual selection).

References

  1. The Oxford Dictionary of Science defines adaptation as "Any change in the structure or functioning of an organism that makes it better suited to its environment".
  2. Bowler P.J. 2003. Evolution: the history of an idea. California. p10
  3. Patterson C. 1999. Evolution. Natural History Museum, London. p1
  4. Williams, George C. 1966. Adaptation and natural selection: a critique of some current evolutionary thought. Princeton. "Evolutionary adaptation is a phenomenon of pervasive importance in biology." p5









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