Natural selection
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Natural selection is the differential survival and reproduction of individuals due to differences in phenotype. It is a key mechanism of evolution, the change in the heritable traits characteristic of a population over generations. Charles Darwin popularised the term "natural selection", contrasting it with artificial selection, which is intentional, whereas natural selection is not.
Variation of traits, both genotypic and phenotypic, exists within all populations of organisms. However, some traits are more likely to facilitate survival and reproductive success. Thus, these traits are passed onto the next generation. These traits can also become more common within a population if the environment that favours these traits remain fixed. If new traits become more favored due to changes in a specific niche, microevolution occurs. If new traits become more favored due to changes in the broader environment, macroevolution occurs. Sometimes, new species can arise especially if these new traits are radically different from the traits possessed by their predecessors.
The likelihood of these traits being 'selected' and passed down are determined by many factors. Some are likely to be passed down because they adapt well to their environments. Others are passed down because these traits are actively preferred by mating partners, which is known as sexual selection. Female bodies also prefer traits that confer the lowest cost to their reproductive health, which is known as fecundity selection.
Natural selection is a cornerstone of modern biology. The concept, published by Darwin and Alfred Russel Wallace in a joint presentation of papers in 1858, was elaborated in Darwin's influential 1859 book On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life. He described natural selection as analogous to artificial selection, a process by which animals and plants with traits considered desirable by human breeders are systematically favoured for reproduction. The concept of natural selection originally developed in the absence of a valid theory of heredity; at the time of Darwin's writing, science had yet to develop modern theories of genetics. The union of traditional Darwinian evolution with subsequent discoveries in classical genetics formed the modern synthesis of the mid-20th century. The addition of molecular genetics has led to evolutionary developmental biology, which explains evolution at the molecular level. While genotypes can slowly change by random genetic drift, natural selection remains the primary explanation for adaptive evolution.
Historical development
Pre-Darwinian theories
Several philosophers of the
So what hinders the different parts [of the body] from having this merely accidental relation in nature? as the teeth, for example, grow by necessity, the front ones sharp, adapted for dividing, and the grinders flat, and serviceable for masticating the food; since they were not made for the sake of this, but it was the result of accident. And in like manner as to the other parts in which there appears to exist an adaptation to an end. Wheresoever, therefore, all things together (that is all the parts of one whole) happened like as if they were made for the sake of something, these were preserved, having been appropriately constituted by an internal spontaneity, and whatsoever things were not thus constituted, perished, and still perish.
— Aristotle, Physics, Book II, Chapter 8[7]
But Aristotle rejected this possibility in the next paragraph, making clear that he is talking about the development of animals as embryos with the phrase "either invariably or normally come about", not the origin of species:
... Yet it is impossible that this should be the true view. For teeth and all other natural things either invariably or normally come about in a given way; but of not one of the results of chance or spontaneity is this true. We do not ascribe to chance or mere coincidence the frequency of rain in winter, but frequent rain in summer we do; nor heat in the dog-days, but only if we have it in winter. If then, it is agreed that things are either the result of coincidence or for an end, and these cannot be the result of coincidence or spontaneity, it follows that they must be for an end; and that such things are all due to nature even the champions of the theory which is before us would agree. Therefore action for an end is present in things which come to be and are by nature.
— Aristotle, Physics, Book II, Chapter 8[8]
The struggle for existence was later described by the Islamic writer Al-Jahiz in the 9th century, particularly in the context of top-down population regulation, but not in reference to individual variation or natural selection.[9][10]
At the turn of the 16th century Leonardo da Vinci collected a set of fossils of ammonites as well as other biological material. He extensively reasoned in his writings that the shapes of animals are not given once and forever by the "upper power" but instead are generated in different forms naturally and then selected for reproduction by their compatibility with the environment.[11]
The more recent classical arguments were reintroduced in the 18th century by Pierre Louis Maupertuis[12] and others, including Darwin's grandfather, Erasmus Darwin.
Until the early 19th century, the
The early 19th-century zoologist
Between 1835 and 1837, the zoologist Edward Blyth worked on the area of variation, artificial selection, and how a similar process occurs in nature. Darwin acknowledged Blyth's ideas in the first chapter on variation of On the Origin of Species.[16]
Darwin's theory
In 1859, Charles Darwin set out his theory of evolution by natural selection as an explanation for adaptation and speciation. He defined natural selection as the "principle by which each slight variation [of a trait], if useful, is preserved".[17] The concept was simple but powerful: individuals best adapted to their environments are more likely to survive and reproduce. As long as there is some variation between them and that variation is heritable, there will be an inevitable selection of individuals with the most advantageous variations. If the variations are heritable, then differential reproductive success leads to the evolution of particular populations of a species, and populations that evolve to be sufficiently different eventually become different species.[18][19]
Darwin's ideas were inspired by the observations that he had made on the second voyage of HMS Beagle (1831–1836), and by the work of a political economist, Thomas Robert Malthus, who, in An Essay on the Principle of Population (1798), noted that population (if unchecked) increases exponentially, whereas the food supply grows only arithmetically; thus, inevitable limitations of resources would have demographic implications, leading to a "struggle for existence".[20] When Darwin read Malthus in 1838 he was already primed by his work as a naturalist to appreciate the "struggle for existence" in nature. It struck him that as population outgrew resources, "favourable variations would tend to be preserved, and unfavourable ones to be destroyed. The result of this would be the formation of new species."[21] Darwin wrote:
If during the long course of ages and under varying conditions of life, organic beings vary at all in the several parts of their organisation, and I think this cannot be disputed; if there be, owing to the high geometrical powers of increase of each species, at some age, season, or year, a severe struggle for life, and this certainly cannot be disputed; then, considering the infinite complexity of the relations of all organic beings to each other and to their conditions of existence, causing an infinite diversity in structure, constitution, and habits, to be advantageous to them, I think it would be a most extraordinary fact if no variation ever had occurred useful to each being's own welfare, in the same way as so many variations have occurred useful to man. But if variations useful to any organic being do occur, assuredly individuals thus characterised will have the best chance of being preserved in the struggle for life; and from the strong principle of inheritance they will tend to produce offspring similarly characterised. This principle of preservation, I have called, for the sake of brevity, Natural Selection.
— Darwin summarising natural selection in the fourth chapter of On the Origin of Species[22]
Once he had his theory, Darwin was meticulous about gathering and refining evidence before making his idea public. He was in the process of writing his "big book" to present his research when the naturalist Alfred Russel Wallace independently conceived of the principle and described it in an essay he sent to Darwin to forward to Charles Lyell. Lyell and Joseph Dalton Hooker decided to present his essay together with unpublished writings that Darwin had sent to fellow naturalists, and On the Tendency of Species to form Varieties; and on the Perpetuation of Varieties and Species by Natural Means of Selection was read to the Linnean Society of London announcing co-discovery of the principle in July 1858.[23] Darwin published a detailed account of his evidence and conclusions in On the Origin of Species in 1859. In the 3rd edition of 1861 Darwin acknowledged that others—like William Charles Wells in 1813, and Patrick Matthew in 1831—had proposed similar ideas, but had neither developed them nor presented them in notable scientific publications.[24]
Darwin thought of natural selection by analogy to how farmers select crops or livestock for breeding, which he called "
For Darwin and his contemporaries, natural selection was in essence synonymous with evolution by natural selection. After the publication of On the Origin of Species,
The modern synthesis
Natural selection relies crucially on the idea of heredity, but developed before the basic concepts of
A second synthesis
Ernst Mayr recognised the key importance of reproductive isolation for speciation in his Systematics and the Origin of Species (1942).[44] W. D. Hamilton conceived of kin selection in 1964.[45][46] This synthesis cemented natural selection as the foundation of evolutionary theory, where it remains today. A second synthesis was brought about at the end of the 20th century by advances in molecular genetics, creating the field of evolutionary developmental biology ("evo-devo"), which seeks to explain the evolution of form in terms of the genetic regulatory programs which control the development of the embryo at molecular level. Natural selection is here understood to act on embryonic development to change the morphology of the adult body.[47][48][49][50]
Terminology
The term natural selection is most often defined to operate on heritable traits, because these directly participate in evolution. However, natural selection is "blind" in the sense that changes in phenotype can give a reproductive advantage regardless of whether or not the trait is heritable. Following Darwin's primary usage, the term is used to refer both to the evolutionary consequence of blind selection and to its mechanisms.[27][37][51][52] It is sometimes helpful to explicitly distinguish between selection's mechanisms and its effects; when this distinction is important, scientists define "(phenotypic) natural selection" specifically as "those mechanisms that contribute to the selection of individuals that reproduce", without regard to whether the basis of the selection is heritable.[53][54][55] Traits that cause greater reproductive success of an organism are said to be selected for, while those that reduce success are selected against.[56]
Mechanism
Heritable variation, differential reproduction
Natural variation occurs among the individuals of any population of organisms. Some differences may improve an individual's chances of surviving and reproducing such that its lifetime reproductive rate is increased, which means that it leaves more offspring. If the traits that give these individuals a reproductive advantage are also
The
Fitness
The concept of fitness is central to natural selection. In broad terms, individuals that are more "fit" have better potential for survival, as in the well-known phrase "survival of the fittest", but the precise meaning of the term is much more subtle. Modern evolutionary theory defines fitness not by how long an organism lives, but by how successful it is at reproducing. If an organism lives half as long as others of its species, but has twice as many offspring surviving to adulthood, its genes become more common in the adult population of the next generation. Though natural selection acts on individuals, the effects of chance mean that fitness can only really be defined "on average" for the individuals within a population. The fitness of a particular genotype corresponds to the average effect on all individuals with that genotype.[61] A distinction must be made between the concept of "survival of the fittest" and "improvement in fitness". "Survival of the fittest" does not give an "improvement in fitness", it only represents the removal of the less fit variants from a population. A mathematical example of "survival of the fittest" is given by Haldane in his paper "The Cost of Natural Selection".[62] Haldane called this process "substitution" or more commonly in biology, this is called "fixation". This is correctly described by the differential survival and reproduction of individuals due to differences in phenotype. On the other hand, "improvement in fitness" is not dependent on the differential survival and reproduction of individuals due to differences in phenotype, it is dependent on the absolute survival of the particular variant. The probability of a beneficial mutation occurring on some member of a population depends on the total number of replications of that variant. The mathematics of "improvement in fitness was described by Kleinman.[63] An empirical example of "improvement in fitness" is given by the Kishony Mega-plate experiment.[64] In this experiment, "improvement in fitness" depends on the number of replications of the particular variant for a new variant to appear that is capable of growing in the next higher drug concentration region. Fixation or substitution is not required for this "improvement in fitness". On the other hand, "improvement in fitness" can occur in an environment where "survival of the fittest" is also acting. Richard Lenski's classic E. coli long-term evolution experiment is an example of adaptation in a competitive environment, ("improvement in fitness" during "survival of the fittest").[65] The probability of a beneficial mutation occurring on some member of the lineage to give improved fitness is slowed by the competition. The variant which is a candidate for a beneficial mutation in this limited carrying capacity environment must first out-compete the "less fit" variants in order to accumulate the requisite number of replications for there to be a reasonable probability of that beneficial mutation occurring.[66]
Competition
In biology, competition is an interaction between organisms in which the fitness of one is lowered by the presence of another. This may be because both rely on a limited supply of a resource such as food, water, or territory.[67] Competition may be within or between species, and may be direct or indirect.[68] Species less suited to compete should in theory either adapt or die out, since competition plays a powerful role in natural selection, but according to the "room to roam" theory it may be less important than expansion among larger clades.[68][69]
Competition is modelled by
Classification
Natural selection can act on any heritable phenotypic trait,[73] and selective pressure can be produced by any aspect of the environment, including sexual selection and competition with members of the same or other species.[74][75] However, this does not imply that natural selection is always directional and results in adaptive evolution; natural selection often results in the maintenance of the status quo by eliminating less fit variants.[57]
Selection can be classified in several different ways, such as by its effect on a trait, on genetic diversity, by the life cycle stage where it acts, by the unit of selection, or by the resource being competed for.
By effect on a trait
Selection has different effects on traits. Stabilizing selection acts to hold a trait at a stable optimum, and in the simplest case all deviations from this optimum are selectively disadvantageous. Directional selection favours extreme values of a trait. The uncommon disruptive selection also acts during transition periods when the current mode is sub-optimal, but alters the trait in more than one direction. In particular, if the trait is quantitative and univariate then both higher and lower trait levels are favoured. Disruptive selection can be a precursor to speciation.[57]
By effect on genetic diversity
Alternatively, selection can be divided according to its effect on
By life cycle stage
Another option is to classify selection by the life cycle stage at which it acts. Some biologists recognise just two types: viability (or survival) selection, which acts to increase an organism's probability of survival, and fecundity (or fertility or reproductive) selection, which acts to increase the rate of reproduction, given survival. Others split the life cycle into further components of selection. Thus viability and survival selection may be defined separately and respectively as acting to improve the probability of survival before and after reproductive age is reached, while fecundity selection may be split into additional sub-components including sexual selection, gametic selection, acting on gamete survival, and compatibility selection, acting on zygote formation.[79]
By unit of selection
Selection can also be classified by the level or
By resource being competed for
Finally, selection can be classified according to the resource being competed for. Sexual selection results from competition for mates. Sexual selection typically proceeds via fecundity selection, sometimes at the expense of viability. Ecological selection is natural selection via any means other than sexual selection, such as kin selection, competition, and infanticide. Following Darwin, natural selection is sometimes defined as ecological selection, in which case sexual selection is considered a separate mechanism.[83]
Sexual selection as first articulated by Darwin (using the example of the peacock's tail)[81] refers specifically to competition for mates,[84] which can be intrasexual, between individuals of the same sex, that is male–male competition, or intersexual, where one gender chooses mates, most often with males displaying and females choosing.[85] However, in some species, mate choice is primarily by males, as in some fishes of the family Syngnathidae.[86][87]
Phenotypic traits can be displayed in one sex and desired in the other sex, causing a positive feedback loop called a Fisherian runaway, for example, the extravagant plumage of some male birds such as the peacock.[82] An alternate theory proposed by the same Ronald Fisher in 1930 is the sexy son hypothesis, that mothers want promiscuous sons to give them large numbers of grandchildren and so choose promiscuous fathers for their children. Aggression between members of the same sex is sometimes associated with very distinctive features, such as the antlers of stags, which are used in combat with other stags. More generally, intrasexual selection is often associated with sexual dimorphism, including differences in body size between males and females of a species.[85]
Arms races
Natural selection is seen in action in the development of
Evolution by means of natural selection
A prerequisite for natural selection to result in adaptive evolution, novel traits and speciation is the presence of heritable genetic variation that results in fitness differences. Genetic variation is the result of mutations,
Some mutations occur in "toolkit" or regulatory genes. Changes in these often have large effects on the phenotype of the individual because they regulate the function of many other genes. Most, but not all, mutations in regulatory genes result in non-viable embryos. Some nonlethal regulatory mutations occur in HOX genes in humans, which can result in a cervical rib[95] or polydactyly, an increase in the number of fingers or toes.[96] When such mutations result in a higher fitness, natural selection favours these phenotypes and the novel trait spreads in the population. Established traits are not immutable; traits that have high fitness in one environmental context may be much less fit if environmental conditions change. In the absence of natural selection to preserve such a trait, it becomes more variable and deteriorate over time, possibly resulting in a vestigial manifestation of the trait, also called evolutionary baggage. In many circumstances, the apparently vestigial structure may retain a limited functionality, or may be co-opted for other advantageous traits in a phenomenon known as preadaptation. A famous example of a vestigial structure, the eye of the blind mole-rat, is believed to retain function in photoperiod perception.[97]
Speciation
Speciation requires a degree of
Genetic basis
Genotype and phenotype
Natural selection acts on an organism's phenotype, or physical characteristics. Phenotype is determined by an organism's genetic make-up (genotype) and the environment in which the organism lives. When different organisms in a population possess different versions of a gene for a certain trait, each of these versions is known as an
Some traits are governed by only a single gene, but most traits are influenced by the interactions of many genes. A variation in one of the many genes that contributes to a trait may have only a small effect on the phenotype; together, these genes can produce a continuum of possible phenotypic values.[102]
Directionality of selection
When some component of a trait is heritable, selection alters the frequencies of the different alleles, or variants of the gene that produces the variants of the trait. Selection can be divided into three classes, on the basis of its effect on allele frequencies:
Some forms of
Selection, genetic variation, and drift
A portion of all genetic variation is functionally neutral, producing no phenotypic effect or significant difference in fitness. Motoo Kimura's neutral theory of molecular evolution by genetic drift proposes that this variation accounts for a large fraction of observed genetic diversity.[108] Neutral events can radically reduce genetic variation through population bottlenecks.[109] which among other things can cause the founder effect in initially small new populations.[110] When genetic variation does not result in differences in fitness, selection cannot directly affect the frequency of such variation. As a result, the genetic variation at those sites is higher than at sites where variation does influence fitness.[103] However, after a period with no new mutations, the genetic variation at these sites is eliminated due to genetic drift. Natural selection reduces genetic variation by eliminating maladapted individuals, and consequently the mutations that caused the maladaptation. At the same time, new mutations occur, resulting in a mutation–selection balance. The exact outcome of the two processes depends both on the rate at which new mutations occur and on the strength of the natural selection, which is a function of how unfavourable the mutation proves to be.[111]
Genetic linkage occurs when the loci of two alleles are close on a chromosome. During the formation of gametes, recombination reshuffles the alleles. The chance that such a reshuffle occurs between two alleles is inversely related to the distance between them. Selective sweeps occur when an allele becomes more common in a population as a result of positive selection. As the prevalence of one allele increases, closely linked alleles can also become more common by "genetic hitchhiking", whether they are neutral or even slightly deleterious. A strong selective sweep results in a region of the genome where the positively selected haplotype (the allele and its neighbours) are in essence the only ones that exist in the population. Selective sweeps can be detected by measuring linkage disequilibrium, or whether a given haplotype is overrepresented in the population. Since a selective sweep also results in selection of neighbouring alleles, the presence of a block of strong linkage disequilibrium might indicate a 'recent' selective sweep near the centre of the block.[112]
Background selection is the opposite of a selective sweep. If a specific site experiences strong and persistent purifying selection, linked variation tends to be weeded out along with it, producing a region in the genome of low overall variability. Because background selection is a result of deleterious new mutations, which can occur randomly in any haplotype, it does not produce clear blocks of linkage disequilibrium, although with low recombination it can still lead to slightly negative linkage disequilibrium overall.[113]
Impact
Darwin's ideas, along with those of Adam Smith and Karl Marx, had a profound influence on 19th century thought, including his radical claim that "elaborately constructed forms, so different from each other, and dependent on each other in so complex a manner" evolved from the simplest forms of life by a few simple principles.[114] This inspired some of Darwin's most ardent supporters—and provoked the strongest opposition. Natural selection had the power, according to Stephen Jay Gould, to "dethrone some of the deepest and most traditional comforts of Western thought", such as the belief that humans have a special place in the world.[115]
In the words of the philosopher Daniel Dennett, "Darwin's dangerous idea" of evolution by natural selection is a "universal acid," which cannot be kept restricted to any vessel or container, as it soon leaks out, working its way into ever-wider surroundings.[116] Thus, in the last decades, the concept of natural selection has spread from evolutionary biology to other disciplines, including evolutionary computation, quantum Darwinism, evolutionary economics, evolutionary epistemology, evolutionary psychology, and cosmological natural selection. This unlimited applicability has been called universal Darwinism.[117]
Origin of life
How life originated from inorganic matter remains an unresolved problem in biology. One prominent hypothesis is that life first appeared in the form of short self-replicating RNA polymers.[118] On this view, life may have come into existence when RNA chains first experienced the basic conditions, as conceived by Charles Darwin, for natural selection to operate. These conditions are: heritability, variation of type, and competition for limited resources. The fitness of an early RNA replicator would likely have been a function of adaptive capacities that were intrinsic (i.e., determined by the nucleotide sequence) and the availability of resources.[119][120] The three primary adaptive capacities could logically have been: (1) the capacity to replicate with moderate fidelity (giving rise to both heritability and variation of type), (2) the capacity to avoid decay, and (3) the capacity to acquire and process resources.[119][120] These capacities would have been determined initially by the folded configurations (including those configurations with ribozyme activity) of the RNA replicators that, in turn, would have been encoded in their individual nucleotide sequences.[121]
Cell and molecular biology
In 1881, the embryologist Wilhelm Roux published Der Kampf der Theile im Organismus (The Struggle of Parts in the Organism) in which he suggested that the development of an organism results from a Darwinian competition between the parts of the embryo, occurring at all levels, from molecules to organs.[122] In recent years, a modern version of this theory has been proposed by Jean-Jacques Kupiec. According to this cellular Darwinism, random variation at the molecular level generates diversity in cell types whereas cell interactions impose a characteristic order on the developing embryo.[123]
Social and psychological theory
The social implications of the theory of evolution by natural selection also became the source of continuing controversy.
More recently, work among anthropologists and psychologists has led to the development of sociobiology and later of evolutionary psychology, a field that attempts to explain features of human psychology in terms of adaptation to the ancestral environment. The most prominent example of evolutionary psychology, notably advanced in the early work of Noam Chomsky and later by Steven Pinker, is the hypothesis that the human brain has adapted to acquire the grammatical rules of natural language.[127] Other aspects of human behaviour and social structures, from specific cultural norms such as incest avoidance to broader patterns such as gender roles, have been hypothesised to have similar origins as adaptations to the early environment in which modern humans evolved. By analogy to the action of natural selection on genes, the concept of memes—"units of cultural transmission," or culture's equivalents of genes undergoing selection and recombination—has arisen, first described in this form by Richard Dawkins in 1976[128] and subsequently expanded upon by philosophers such as Daniel Dennett as explanations for complex cultural activities, including human consciousness.[129]
Information and systems theory
In 1922, Alfred J. Lotka proposed that natural selection might be understood as a physical principle that could be described in terms of the use of energy by a system,[130][131] a concept later developed by Howard T. Odum as the maximum power principle in thermodynamics, whereby evolutionary systems with selective advantage maximise the rate of useful energy transformation.[132]
The principles of natural selection have inspired a variety of computational techniques, such as "soft"
In fiction
Darwinian evolution by natural selection is pervasive in literature, whether taken optimistically in terms of how humanity may evolve towards perfection, or pessimistically in terms of the dire consequences of the interaction of human nature and the struggle for survival. Among major responses is
Notes
- ^ In sexual selection, a female animal making a choice of mate may be argued to be intending to get the best mate; there is no suggestion that she has any intention to improve the bloodline in the manner of an animal breeder.
References
- ^ Empedocles 1898, On Nature, Book II
- ^ Lucretius 1916, On the Nature of Things, Book V
- ^ Aristotle, Physics, Book II, Chapters 4 and 8
- ^ Lear 1988, p. 38
- S2CID 85671523.
- ^ Ariew 2002
- ^ Darwin 1872, p. xiii
- ^ Aristotle, Physics, Book II, Chapter 8
- JSTOR 984852.
- ^ Agutter & Wheatley 2008, p. 43
- ^ Leonardo, Codex C. Institut of France. Trans. Richter. 2016.
- ^ Maupertuis, Pierre Louis (1746). ["Derivation of the laws of motion and equilibrium from a metaphysical principle"]. Histoire de l'Académie Royale des Sciences et des Belles Lettres (in French). Berlin: 267–294.
- OCLC 43091892.
- ^ Lamarck 1809
- JSTOR 2707968.
- ^ Darwin 1859, p. 18
- ^ Darwin 1859, p. 61
- ^ Darwin 1859, p. 5
- OCLC 796450355.
- ^ Malthus 1798
- ^ Darwin 1958, p. 120
- ^ Darwin 1859, pp. 126–127
- ^ Wallace 1871
- ^ Darwin 1861, p. xiii
- ^ Darwin 1859, p. 6
- ^ Darwin, Charles (28 September 1860). "Darwin, C. R. to Lyell, Charles". Darwin Correspondence Project. Cambridge, UK: Cambridge University Library. Letter 2931. Retrieved 1 August 2015.
- ^ a b Darwin 1859
- ^ Eisley 1958
- ^ Kuhn 1996
- ^ Darwin, Charles (5 July 1866). "Darwin, C. R. to Wallace, A. R." Darwin Correspondence Project. Cambridge, UK: Cambridge University Library. Letter 5145. Retrieved 12 January 2010.
- ^ Stucke, Maurice E. (Summer 2008). "Better Competition Advocacy". St. John's Law Review. 82 (3). Jamaica, NY: 951–1036.
This survival of the fittest, which I have here sought to express in mechanical terms, is that which Mr. Darwin has called 'natural selection, or the preservation of favoured races in the struggle for life.'
—Herbert Spencer, Principles of Biology (1864), vol. 1, pp. 444–445 - ^ Darwin 1872, p. 49.
- S2CID 38015862. Archived from the original(PDF) on 25 December 2015. Retrieved 4 August 2015.
- ^ Ambrose, Mike. "Mendel's Peas". Norwich, UK: Germplasm Resources Unit, John Innes Centre. Archived from the original on 14 June 2016. Retrieved 22 May 2015.
- OCLC 3171056.
- OCLC 43803228.
- ^ a b Fisher 1930
- ^ Haldane 1932
- S2CID 32233460.
- ^ Wright, Sewall (1932). "The roles of mutation, inbreeding, crossbreeding and selection in evolution". Proceedings of the VI International Congress of Genetrics. 1: 356–366.
- ^ Dobzhansky 1937
- ^ Dobzhansky 1951
- ISBN 978-1-4051-1950-4.
- ^ Mayr 1942
- S2CID 5310280.
- PMID 5875340.
- PMID 14756322.
- PMID 8605997.
- S2CID 19264907.
- ISBN 978-1-4051-1950-4.
- ^ Williams 1966
- ^ Endler 1986
- ^ Haldane 1954
- PMID 28556011.
- ^ Futuyma 2005
- ^ Sober 1993
- ^ a b c "Evolution and Natural Selection". University of Michigan. 10 October 2010. Retrieved 9 November 2016.
- ^ "Teleological Notions in Biology". Stanford Encyclopedia of Philosophy. 18 May 2003. Retrieved 28 July 2016.
- S2CID 3989607.
- PMID 30271998.
- PMID 19546856.
- ^ Haldane, J. B. S. (November 1992). "The Cost of Natural Selection". Current Science. 63 (9/10): 612–625.
- PMID 25244620.
- PMID 27609891.
- PMID 18524956.
- PMID 22371564.
- ^ Begon, Townsend & Harper 1996
- ^ PMID 20106856.
- .
- ^ MacArthur & Wilson 2001
- S2CID 83933177.
- ^ OCLC 490225808.
- ^ Zimmer & Emlen 2013
- ^ Miller 2000, p. 8
- OCLC 937342534.
- ^ Lemey, Salemi & Vandamme 2009
- OCLC 310450541.
- PMID 25946124.
- ^ a b Christiansen 1984, pp. 65–79
- PMID 20164866.
- ^ a b Darwin, Charles (1859). On the Origin of Species (1st edition). Chapter 4, page 88. "And this leads me to say a few words on what I call Sexual Selection. This depends ..." http://darwin-online.org.uk/content/frameset?viewtype=side&itemID=F373&pageseq=12
- ^ S2CID 2619084.
- ^ Mayr 2006
- ^ Andersson 1994
- ^ S2CID 18470445.
- S2CID 20732874.
- S2CID 44774132.
- ^ Harvey, Fiona; Carson, Mary; O'Kane, Maggie; Wasley, Andrew (18 June 2015). "MRSA superbug found in supermarket pork raises alarm over farming risks". The Guardian.
- PMID 16445718.
- S2CID 45723069.
- PMID 16914702.
- PMID 15994173.
- S2CID 2790337.
- PMID 16547091.
- PMID 10327647.
- PMID 9391088.
- PMID 2142147.
- PMID 8978022.
- ISBN 978-0-691-11983-0
- ^ Schuler, Hannes; Hood, Glen R.; Egan, Scott P.; Feder, Jeffrey L. (2016). "Modes and Mechanisms of Speciation". Reviews in Cell Biology and Molecular Medicine. 2 (3): 60–93.
- ^ McKusick, Victor A.; Gross, Matthew B. (18 November 2014). "ABO Glycosyltransferase; ABO". Online Mendelian Inheritance in Man. National Library of Medicine. Retrieved 7 November 2016.
- ^ Falconer & Mackay 1996
- ^ a b Rice 2004, See especially chapters 5 and 6 for a quantitative treatment
- PMID 12221290.
- S2CID 27361293.
- PMID 5875340.
- S2CID 19027999.
- OCLC 8776549.
- OCLC 3373856121.
- OCLC 3138680061.
- PMID 20594608.
- PMID 4407212.
- S2CID 4422532.
- ^ Darwin 1859, p. 489
- ^ Gould, Stephen Jay (12 June 1997). "Darwinian Fundamentalism". The New York Review of Books. 44 (10).
- ^ Dennett 1995
- OCLC 1088022023.
- PMID 6164094.
- ^ S2CID 83956410.
- ^ a b Michod 1999
- PMID 2456886.
- ^ Roux 1881
- ^ Kupiec, Jean-Jacques [in French] (3 May 2010). "Cellular Darwinism (stochastic gene expression in cell differentiation and embryo development)". SciTopics. Archived from the original on 4 August 2010. Retrieved 11 August 2015.
- ^ Engels 1964
- PMID 16135651. Eisenberg quoting translation of Durch Domestikation verursachte Störungen arteigenen Verhaltens (1940, p. 2) by Konrad Lorenz.
- ^ Wilson 2002
- ^ Pinker 1995
- ^ Dawkins 1976, p. 192
- ^ Dennett 1991
- PMID 16576642.
- PMID 16576643.
- ^ Odum, H. T. (1995). Hall, C. A. S. (ed.). Self-Organization and Maximum Empower. Colorado University Press.
- ^ Kauffman 1993
- ^ Goldberg 1989
- ^ Mitchell 1996
- ^ "Genetic Algorithms". Pharmacological Sciences. 7 November 2016. Retrieved 7 November 2016.
- ^ Stableford, Brian M.; Langford, David R. (5 July 2018). "Evolution". The Encyclopedia of Science Fiction. Gollancz. Retrieved 24 July 2018.
Sources
- Agutter, Paul S.; Wheatley, Denys N. (2008). Thinking about Life: The History and Philosophy of Biology and Other Sciences. Dordrecht, the Netherlands; London: OCLC 304561132.
- Andersson, Malte (1994). Sexual Selection. Monographs in Behavior and Ecology. Princeton, NJ: OCLC 28891551.
- Ariew, André (2002). "Platonic and Aristotelian Roots of Teleological Arguments" (PDF). In Ariew, André; Cummins, Robert; Perlman, Mark (eds.). Functions: New Essays in the Philosophy of Psychology and Biology. Oxford; New York: OCLC 48965141. Archived from the original(PDF) on 19 February 2009.
- OCLC 54350394.
- Begon, Michael; Townsend, Colin R.; OCLC 32893848.
- Christiansen, Freddy B. (1984). "The Definition and Measurement of Fitness". In Shorrocks, Bryan (ed.). Evolutionary Ecology: The 23rd Symposium of the British Ecological Society, Leeds, 1982. Symposium of the OCLC 12586581. Modified from Christiansen by adding survival selection in the reproductive phase.
- OCLC 741260650. The book is available from The Complete Work of Charles Darwin Online. Retrieved 2015-07-23.
- Darwin, Charles (1861). On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life (3rd ed.). London: John Murray. OCLC 550913.
- Darwin, Charles (1872). The Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life (6th ed.). London: John Murray. OCLC 1185571.
- Darwin, Charles (1958). Barlow, Nora (ed.). The Autobiography of Charles Darwin, 1809–1882: With original omissions restored; Edited and with Appendix and Notes by his grand-daughter, Nora Barlow. London: OCLC 869541868.
- OCLC 2681149.
- OCLC 23648691.
- Dennett, Daniel C. (1995). OCLC 31867409.
- OCLC 766405.
- —— (1951). Genetics and the Origin of Species. Columbia University Biological Series (3rd revised ed.). New York: Columbia University Press. OCLC 295774.
- —— (1951). Genetics and the Origin of Species. Columbia University Biological Series (3rd revised ed.). New York: Columbia University Press.
- OCLC 168989.
- .
- OCLC 12262762.
- OCLC 807047245. The book is available from the Marxist Internet Archive.
- OCLC 824656731.
- OCLC 493745635.
- OCLC 57311264.
- OCLC 17674450.
- OCLC 5006266. "This book is based on a series of lectures delivered in January 1931 at the Prifysgol Cymru, Aberystwyth, and entitled 'A re-examination of Darwinism'."
- OCLC 9069245.
- OCLC 23253930.
- .
- OCLC 16352317.
- OCLC 34548541.
- Lemey, Philippe; Salemi, Marco; Vandamme, Anne-Mieke, eds. (2009). The Phylogenetic Handbook: A Practical Approach to Phylogenetic Analysis and Hypothesis Testing (2nd ed.). Cambridge, UK; New York: Cambridge University Press. OCLC 295002266.
- OCLC 33233743.
- OCLC 45202069.
- .
- OCLC 766053.
- Mayr, Ernst (2006) [Originally published 1972; Chicago, IL: Aldine Publishing Co.]. "Sexual Selection and Natural Selection". In Campbell, Bernard G. (ed.). Sexual Selection and the Descent of Man: The Darwinian Pivot. New Brunswick, NJ: OCLC 62857839.
- Michod, Richard A. (1999). Darwinian Dynamics: Evolutionary Transitions in Fitness and Individuality. Princeton, NJ: Princeton University Press. OCLC 38948118.
- OCLC 43648482.
- OCLC 42854439.
- OCLC 670524593.
- Rice, Sean H. (2004). Evolutionary Theory: Mathematical and Conceptual Foundations. Sunderland, MA: Sinauer Associates. OCLC 54988554.
- Retrieved 2015-08-11.
- OCLC 896826726.
- OCLC 809350209.
- OCLC 35230452.
- OCLC 48777441.
- OCLC 767565909.
Further reading
- For technical audiences
- OCLC 170034792.
- Johnson, Clifford (1976). Introduction to Natural Selection. Baltimore, MD: University Park Press. OCLC 2091640.
- OCLC 47869352.
- OCLC 27676642.
- ISSN 0012-2017.
- Sammut-Bonnici, Tanya; Wensley, Robin (September 2002). "Darwinism, probability and complexity: Market-based organizational transformation and change explained through the theories of evolution" (PDF). ISSN 1460-8545.
- OCLC 28150417.
- OCLC 228136567.
- For general audiences
- Historical
External links
- Darwin, Charles. "On the Origin of Species". Archived from the original on 25 February 2001. – Chapter 4, Natural Selection