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79-493: Lamarckism , also known as Lamarckian inheritance or neo-Lamarckism , is the notion that an organism can pass on to its offspring physical characteristics that the parent organism acquired through use or disuse during its lifetime. It is also called the inheritance of acquired characteristics or more recently soft inheritance . The idea is named after the French zoologist Jean-Baptiste Lamarck (1744–1829), who incorporated

158-442: A Darwinian framework. However, the significance of epigenetics in evolution is uncertain. Critics such as the evolutionary biologist Jerry Coyne point out that epigenetic inheritance lasts for only a few generations, so it is not a stable basis for evolutionary change. The evolutionary biologist T. Ryan Gregory contends that epigenetic inheritance should not be considered Lamarckian. According to Gregory, Lamarck did not claim that

237-627: A Lamarckian element in evolution but the processes do not challenge the main tenets of the modern evolutionary synthesis as modern Lamarckians have claimed. Haig argued for the primacy of DNA and evolution of epigenetic switches by natural selection. Haig has written that there is a "visceral attraction" to Lamarckian evolution from the public and some scientists, as it posits the world with a meaning, in which organisms can shape their own evolutionary destiny. Thomas Dickens and Qazi Rahman (2012) have argued that epigenetic mechanisms such as DNA methylation and histone modification are genetically inherited under

316-511: A change in DNA sequence (genotype) and that such changes may be induced spontaneously or in response to environmental factors—Lamarck's "acquired traits." Determining which observed phenotypes are genetically inherited and which are environmentally induced remains an important and ongoing part of the study of genetics, developmental biology, and medicine. The prokaryotic CRISPR system and Piwi-interacting RNA could be classified as Lamarckian, within

395-434: A factor that Lamarck rejected: inheritance of direct effects of the environment" and neo-Lamarckism is closer to Darwin's pangenesis than Lamarck's views. Simpson wrote, "the inheritance of acquired characters, failed to meet the tests of observation and has been almost universally discarded by biologists." Zirkle pointed out that Lamarck did not originate the hypothesis that acquired characteristics could be inherited , so it

474-569: A few enzymes and molecules like those in living organisms, they have no metabolism of their own; they cannot synthesize the organic compounds from which they are formed. In this sense, they are similar to inanimate matter. Viruses have their own genes , and they evolve . Thus, an argument that viruses should be classed as living organisms is their ability to undergo evolution and replicate through self-assembly. However, some scientists argue that viruses neither evolve nor self-reproduce. Instead, viruses are evolved by their host cells, meaning that there

553-422: A few fleeting passages that look upon organic transmutation with favor." From thus meditating on the great similarity of the structure of the warm-blooded animals, and at the same time of the great changes they undergo both before and after their nativity; and by considering in how minute a proportion of time many of the changes of animals above described have been produced; would it be too bold to imagine, that in

632-442: A limited validity of Lamarckism. The inheritance of the hologenome , consisting of the genomes of all an organism's symbiotic microbes as well as its own genome, is also somewhat Lamarckian in effect, though entirely Darwinian in its mechanisms. The inheritance of acquired characteristics was proposed in ancient times and remained a current idea for many centuries. The historian of science Conway Zirkle wrote in 1935 that: Lamarck

711-442: A misnomer, and truly a discredit to the memory of a man and his much more comprehensive system." The period of the history of evolutionary thought between Darwin's death in the 1880s, and the foundation of population genetics in the 1920s and the beginnings of the modern evolutionary synthesis in the 1930s, is called the eclipse of Darwinism by some historians of science. During that time many scientists and philosophers accepted

790-468: A neo-Lamarckian view of human evolution. The German anthropologist Hermann Klaatsch relied on a neo-Lamarckian model of evolution to try and explain the origin of bipedalism . Neo-Lamarckism remained influential in biology until the 1940s when the role of natural selection was reasserted in evolution as part of the modern evolutionary synthesis. Herbert Graham Cannon , a British zoologist, defended Lamarckism in his 1959 book Lamarck and Modern Genetics . In

869-466: A new habit when faced with an environmental challenge and shape the whole future course of evolution. Scientists from the 1860s onwards conducted numerous experiments that purported to show Lamarckian inheritance. Some examples are described in the table. A century after Lamarck, scientists and philosophers continued to seek mechanisms and evidence for the inheritance of acquired characteristics. Experiments were sometimes reported as successful, but from

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948-466: A process of recombination (a primitive form of sexual interaction ). Zoonomia Zoonomia; or the Laws of Organic Life (1794–96) is a two-volume medical work by Erasmus Darwin dealing with pathology , anatomy , psychology , and the functioning of the body. Its primary framework is one of associationist psychophysiology . The book is now best remembered for its early ideas relating to

1027-465: A systematic theoretical framework for understanding evolution. He saw evolution as comprising four laws: In 1830, in an aside from his evolutionary framework, Lamarck briefly mentioned two traditional ideas in his discussion of heredity, in his day considered to be generally true. The first was the idea of use versus disuse; he theorized that individuals lose characteristics they do not require, or use, and develop characteristics that are useful. The second

1106-411: A tail or even with a shorter tail. In 1889, he stated that "901 young were produced by five generations of artificially mutilated parents, and yet there was not a single example of a rudimentary tail or of any other abnormality in this organ." The experiment, and the theory behind it, were thought at the time to be a refutation of Lamarckism. The experiment's effectiveness in refuting Lamarck's hypothesis

1185-445: Is a microorganism such as a protist , bacterium , or archaean , composed of a single cell , which may contain functional structures called organelles . A multicellular organism such as an animal , plant , fungus , or alga is composed of many cells, often specialised. A colonial organism such as a siphonophore is a being which functions as an individual but is composed of communicating individuals. A superorganism

1264-401: Is a teleonomic or goal-seeking behaviour that enables them to correct errors of many kinds so as to achieve whatever result they are designed for. Such behaviour is reminiscent of intelligent action by organisms; intelligence is seen as an embodied form of cognition . All organisms that exist today possess a self-replicating informational molecule (genome), and such an informational molecule

1343-741: Is a colony, such as of ants , consisting of many individuals working together as a single functional or social unit . A mutualism is a partnership of two or more species which each provide some of the needs of the other. A lichen consists of fungi and algae or cyanobacteria , with a bacterial microbiome ; together, they are able to flourish as a kind of organism, the components having different functions, in habitats such as dry rocks where neither could grow alone. The evolutionary biologists David Queller and Joan Strassmann state that "organismality" has evolved socially, as groups of simpler units (from cells upwards) came to cooperate without conflicts. They propose that cooperation should be used as

1422-491: Is a loose grouping of largely heterodox theories and mechanisms that emerged after Lamarck's time, rather than a coherent body of theoretical work. Neo-Lamarckian versions of evolution were widespread in the late 19th century. The idea that living things could to some degree choose the characteristics that would be inherited allowed them to be in charge of their own destiny as opposed to the Darwinian view, which placed them at

1501-535: Is an argument for viewing viruses as cellular organisms. Some researchers perceive viruses not as virions alone, which they believe are just spores of an organism, but as a virocell - an ontologically mature viral organism that has cellular structure. Such virus is a result of infection of a cell and shows all major physiological properties of other organisms: metabolism , growth, and reproduction , therefore, life in its effective presence. The philosopher Jack A. Wilson examines some boundary cases to demonstrate that

1580-402: Is divided into four major sections, based on his four classes of disease: diseases of irritation, sensation, volition, and association. Encyclopedia-style entries on various diseases explain their symptoms and underlying mechanics, followed by suggestions for treatment. After the fourth class of diseases, Darwin presents a lengthy explanation of his own theory of fever, which he says "may be termed

1659-461: Is doubtful, as it did not address the use and disuse of characteristics in response to the environment. The biologist Peter Gauthier noted in 1990 that: Can Weismann's experiment be considered a case of disuse? Lamarck proposed that when an organ was not used, it slowly, and very gradually atrophied. In time, over the course of many generations, it would gradually disappear as it was inherited in its modified form in each successive generation. Cutting

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1738-497: Is incorrect to refer to it as Lamarckism: What Lamarck really did was to accept the hypothesis that acquired characters were heritable, a notion which had been held almost universally for well over two thousand years and which his contemporaries accepted as a matter of course, and to assume that the results of such inheritance were cumulative from generation to generation, thus producing, in time, new species. His individual contribution to biological theory consisted in his application to

1817-472: Is likely intrinsic to life. Thus, the earliest organisms also presumably possessed a self-replicating informational molecule ( genome ), perhaps RNA or an informational molecule more primitive than RNA. The specific nucleotide sequences in all currently extant organisms contain information that functions to promote survival, reproduction , and the ability to acquire resources necessary for reproduction, and sequences with such functions probably emerged early in

1896-810: Is prone to wish-fulfilling interpretation." A form of Lamarckism was revived in the Soviet Union of the 1930s when Trofim Lysenko promoted the ideologically driven research programme, Lysenkoism ; this suited the ideological opposition of Joseph Stalin to genetics . Lysenkoism influenced Soviet agricultural policy which in turn was later blamed for the numerous massive crop failures experienced within Soviet states. George Gaylord Simpson in his book Tempo and Mode in Evolution (1944) claimed that experiments in heredity have failed to corroborate any Lamarckian process. Simpson noted that neo-Lamarckism "stresses

1975-548: The Ancient Greek ὀργανισμός , derived from órganon , meaning instrument, implement, tool, organ of sense or apprehension) first appeared in the English language in the 1660s with the now-obsolete meaning of an organic structure or organization. It is related to the verb "organize". In his 1790 Critique of Judgment , Immanuel Kant defined an organism as "both an organized and a self-organizing being". Among

2054-563: The blood of one variety of rabbit into another variety in the expectation that its offspring would show some characteristics of the first. They did not, and Galton declared that he had disproved Darwin's hypothesis of pangenesis, but Darwin objected, in a letter to the scientific journal Nature , that he had done nothing of the sort, since he had never mentioned blood in his writings. He pointed out that he regarded pangenesis as occurring in protozoa and plants , which have no blood, as well as in animals. Between 1800 and 1830, Lamarck proposed

2133-558: The classical era theory of soft inheritance into his theory of evolution as a supplement to his concept of orthogenesis , a drive towards complexity . Introductory textbooks contrast Lamarckism with Charles Darwin 's theory of evolution by natural selection . However, Darwin's book On the Origin of Species gave credence to the idea of heritable effects of use and disuse, as Lamarck had done, and his own concept of pangenesis similarly implied soft inheritance. Many researchers from

2212-545: The gonads contain information that passes from one generation to the next, unaffected by experience, and independent of the somatic (body) cells. This implied what came to be known as the Weismann barrier , as it would make Lamarckian inheritance from changes to the body difficult or impossible. Weismann conducted the experiment of removing the tails of 68 white mice , and those of their offspring over five generations, and reporting that no mice were born in consequence without

2291-578: The theory of evolution , specifically forms of developmentalism similar to Lamarckism . However, despite Erasmus Darwin's familial connection as grandfather to Charles Darwin , the proto-evolutionary ideas in Zoonomia did not have a lasting influence. The first volume, published in 1794, is divided into 40 sections, on a range of topics related to the body, the senses, and disease. He classifies bodily and sensory motions as "irritative", "sensitive", "voluntary", and "associative". He presents theories on

2370-642: The "defining trait" of an organism. Samuel Díaz‐Muñoz and colleagues (2016) accept Queller and Strassmann's view that organismality can be measured wholly by degrees of cooperation and of conflict. They state that this situates organisms in evolutionary time, so that organismality is context dependent. They suggest that highly integrated life forms, which are not context dependent, may evolve through context-dependent stages towards complete unification. Viruses are not typically considered to be organisms, because they are incapable of autonomous reproduction , growth , metabolism , or homeostasis . Although viruses have

2449-453: The 1860s onwards attempted to find evidence for Lamarckian inheritance, but these have all been explained away, either by other mechanisms such as genetic contamination or as fraud . August Weismann 's experiment, considered definitive in its time, is now considered to have failed to disprove Lamarckism, as it did not address use and disuse. Later, Mendelian genetics supplanted the notion of inheritance of acquired traits, eventually leading to

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2528-493: The 1960s, "biochemical Lamarckism" was advocated by the embryologist Paul Wintrebert . Neo-Lamarckism was dominant in French biology for more than a century. French scientists who supported neo-Lamarckism included Edmond Perrier (1844–1921), Alfred Giard (1846–1908), Gaston Bonnier (1853–1922) and Pierre-Paul Grassé (1895–1985). They followed two traditions, one mechanistic, one vitalistic after Henri Bergson 's philosophy of evolution . In 1987, Ryuichi Matsuda coined

2607-451: The Name of Science (1957): A host of experiments have been designed to test Lamarckianism. All that have been verified have proved negative. On the other hand, tens of thousands of experiments— reported in the journals and carefully checked and rechecked by geneticists throughout the world— have established the correctness of the gene-mutation theory beyond all reasonable doubt... In spite of

2686-605: The Oxygenation of the Blood in the Lungs and Placenta" and "Of Generation" develop his theories about human reproduction, including observations related to evolution. The final chapter in the first volume is a reprint of a paper by another of Erasmus Darwin's sons, Robert Darwin , about "ocular spectra" ( afterimages ). The second volume, published in 1796, is focused on classifying diseases into classes, orders, and genera. The book

2765-465: The actions of external agents. Lamarck was not concerned with wounds, injuries or mutilations, and nothing that Lamarck had set forth was tested or "disproven" by the Weismann tail-chopping experiment. The historian of science Rasmus Winther stated that Weismann had nuanced views about the role of the environment on the germ plasm. Indeed, like Darwin, he consistently insisted that a variable environment

2844-480: The beginning these were either criticised on scientific grounds or shown to be fakes. For instance, in 1906, the philosopher Eugenio Rignano argued for a version that he called "centro-epigenesis", but it was rejected by most scientists. Some of the experimental approaches are described in the table. The British anthropologist Frederic Wood Jones and the South African paleontologist Robert Broom supported

2923-484: The body, though not necessarily in the bloodstream . These pangenes were microscopic particles that supposedly contained information about the characteristics of their parent cell, and Darwin believed that they eventually accumulated in the germ cells where they could pass on to the next generation the newly acquired characteristics of the parents. Darwin's half-cousin, Francis Galton , carried out experiments on rabbits , with Darwin's cooperation, in which he transfused

3002-532: The cause of all organic life? In Zoonomia , Erasmus Darwin advocated the inheritance of acquired characteristics . He stated, "[F]rom their first rudiment, or primordium, to the termination of their lives, all animals undergo perpetual transformations; which are in part produced by their own exertions in consequence of their desires and aversions, of their pleasures and their pains, or of irritations, or of associations; and many of these acquired forms or propensities are transmitted to their posterity." This statement

3081-678: The concept of organism is not sharply defined. In his view, sponges , lichens , siphonophores , slime moulds , and eusocial colonies such as those of ants or naked molerats , all lie in the boundary zone between being definite colonies and definite organisms (or superorganisms). Scientists and bio-engineers are experimenting with different types of synthetic organism , from chimaeras composed of cells from two or more species, cyborgs including electromechanical limbs, hybrots containing both electronic and biological elements, and other combinations of systems that have variously evolved and been designed. An evolved organism takes its form by

3160-425: The context of epigenetics is misleading, commenting, "We should remember [Lamarck] for the good he contributed to science, not for things that resemble his theory only superficially. Indeed, thinking of CRISPR and other phenomena as Lamarckian only obscures the simple and elegant way evolution really works." Organism The evolutionary biologists David Queller and Joan Strassmann state that "organismality",

3239-441: The control of natural selection and do not challenge the modern synthesis. They dispute the claims of Jablonka and Lamb on Lamarckian epigenetic processes. In 2015, Khursheed Iqbal and colleagues discovered that although "endocrine disruptors exert direct epigenetic effects in the exposed fetal germ cells, these are corrected by reprogramming events in the next generation." Also in 2015, Adam Weiss argued that bringing back Lamarck in

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3318-476: The criteria that have been proposed for being an organism are: Other scientists think that the concept of the organism is inadequate in biology; that the concept of individuality is problematic; and from a philosophical point of view, question whether such a definition is necessary. Problematic cases include colonial organisms : for instance, a colony of eusocial insects fulfills criteria such as adaptive organisation and germ-soma specialisation. If so,

3397-460: The development of the modern synthesis , and the general abandonment of Lamarckism in biology . Despite this, interest in Lamarckism has continued. In the 21st century, experimental results in the fields of epigenetics , genetics , and somatic hypermutation demonstrated the possibility of transgenerational epigenetic inheritance of traits acquired by the previous generation. These proved

3476-471: The effects of environmental stress on the growth of plants, in the belief that such environmentally-induced variation might explain much of plant evolution , and the American entomologist Alpheus Spring Packard Jr. , who studied blind animals living in caves and wrote a book in 1901 about Lamarck and his work. Also included were paleontologists like Edward Drinker Cope and Alpheus Hyatt , who observed that

3555-504: The environment directly affected living things. Instead, Lamarck "argued that the environment created needs to which organisms responded by using some features more and others less, that this resulted in those features being accentuated or attenuated, and that this difference was then inherited by offspring." Gregory has stated that Lamarckian evolution in epigenetics is more like Darwin's point of view than Lamarck's. In 2007, David Haig wrote that research into epigenetic processes does allow

3634-553: The evidence to deny the Lamarckian hypothesis, since it lacks a key factor, namely the willful exertion of the animal in overcoming environmental obstacles. Ghiselin also considered the Weismann tail-chopping experiment to have no bearing on the Lamarckian hypothesis, writing in 1994 that: The acquired characteristics that figured in Lamarck's thinking were changes that resulted from an individual's own drives and actions, not from

3713-422: The evolution of life. It is also likely that survival sequences present early in the evolution of organisms included sequences that facilitate the avoidance of damage to the self-replicating molecule and promote the capability to repair such damages that do occur. Repair of some of the genome damages in these early organisms may have involved the capacity to use undamaged information from another similar genome by

3792-425: The final chapter of his book The Variation of Animals and Plants Under Domestication (1868), which gave numerous examples to demonstrate what he thought was the inheritance of acquired characteristics. Pangenesis, which he emphasised was a hypothesis, was based on the idea that somatic cells would, in response to environmental stimulation (use and disuse), throw off ' gemmules ' or 'pangenes' which travelled around

3871-546: The following two laws: English translation: In essence, a change in the environment brings about change in "needs" ( besoins ), resulting in change in behaviour, causing change in organ usage and development, bringing change in form over time—and thus the gradual transmutation of the species . As the evolutionary biologists and historians of science Conway Zirkle, Michael Ghiselin , and Stephen Jay Gould have pointed out, these ideas were not original to Lamarck. August Weismann 's germ plasm theory held that germline cells in

3950-672: The fossil record showed orderly, almost linear, patterns of development that they felt were better explained by Lamarckian mechanisms than by natural selection. Some people, including Cope and the Darwin critic Samuel Butler , felt that inheritance of acquired characteristics would let organisms shape their own evolution, since organisms that acquired new habits would change the use patterns of their organs, which would kick-start Lamarckian evolution. They considered this philosophically superior to Darwin's mechanism of random variation acted on by selective pressures. Lamarckism also appealed to those, like

4029-413: The great length of time, since the earth began to exist, perhaps millions of years...that all warm-blooded animals have arisen from one living filament, which THE GREAT FIRST CAUSE endued with animality...and thus possessing the faculty of continuing to improve by its own inherent activity, and of delivering down those improvements by generation to its posterity, world without end?... Shall we then say that

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4108-533: The inheritance of acquired characteristics, just as Lamarck did, and Darwin even thought that there was some experimental evidence to support it." Gould wrote that in the late 19th century, evolutionists "re-read Lamarck, cast aside the guts of it ... and elevated one aspect of the mechanics—inheritance of acquired characters—to a central focus it never had for Lamarck himself." He argued that "the restriction of 'Lamarckism' to this relatively small and non-distinctive corner of Lamarck's thought must be labelled as more than

4187-437: The inheritance of behavioral traits, for example in chickens, rats and human populations that have experienced starvation, DNA methylation resulting in altered gene function in both the starved population and their offspring. Methylation similarly mediates epigenetic inheritance in plants such as rice. Small RNA molecules, too, may mediate inherited resistance to infection. Handel and Ramagopalan commented that "epigenetics allows

4266-494: The kind occurs—or can occur—but the notion persists for a variety of nonscientific reasons." Medawar stated there is no known mechanism by which an adaptation acquired in an individual's lifetime can be imprinted on the genome and Lamarckian inheritance is not valid unless it excludes the possibility of natural selection, but this has not been demonstrated in any experiment. Martin Gardner wrote in his book Fads and Fallacies in

4345-404: The making of the phenotype and that the phenotype, in turn, does not control the composition of the DNA." Peter J. Bowler has written that although many early scientists took Lamarckism seriously, it was discredited by genetics in the early twentieth century. Studies in the field of epigenetics , genetics and somatic hypermutation have highlighted the possible inheritance of traits acquired by

4424-440: The mercy of the environment. Such ideas were more popular than natural selection in the late 19th century as it made it possible for biological evolution to fit into a framework of a divine or naturally willed plan, thus the neo-Lamarckian view of evolution was often advocated by proponents of orthogenesis. According to the historian of science Peter J. Bowler, writing in 2003: One of the most emotionally compelling arguments used by

4503-409: The neo-Lamarckians of the late nineteenth century was the claim that Darwinism was a mechanistic theory which reduced living things to puppets driven by heredity. The selection theory made life into a game of Russian roulette, where life or death was predetermined by the genes one inherited. The individual could do nothing to mitigate bad heredity. Lamarckism, in contrast, allowed the individual to choose

4582-501: The partially understood mechanisms of evolutionary developmental biology , in which the genome directs an elaborated series of interactions to produce successively more elaborate structures. The existence of chimaeras and hybrids demonstrates that these mechanisms are "intelligently" robust in the face of radically altered circumstances at all levels from molecular to organismal. Synthetic organisms already take diverse forms, and their diversity will increase. What they all have in common

4661-426: The peaceful co-existence of Darwinian and Lamarckian evolution." Joseph Springer and Dennis Holley commented in 2013 that: Lamarck and his ideas were ridiculed and discredited. In a strange twist of fate, Lamarck may have the last laugh. Epigenetics, an emerging field of genetics, has shown that Lamarck may have been at least partially correct all along. It seems that reversible and heritable changes can occur without

4740-599: The philosopher Herbert Spencer and the German anatomist Ernst Haeckel , who saw evolution as an inherently progressive process. The German zoologist Theodor Eimer combined Larmarckism with ideas about orthogenesis , the idea that evolution is directed towards a goal. With the development of the modern synthesis of the theory of evolution, and a lack of evidence for a mechanism for acquiring and passing on new characteristics, or even their heritability, Lamarckism largely fell from favour. Unlike neo-Darwinism , neo-Lamarckism

4819-432: The power of acquiring new parts" in response to stimuli, with each round of "improvements" being inherited by successive generations. Charles Darwin 's On the Origin of Species proposed natural selection as the main mechanism for development of species, but (like Lamarck) gave credence to the idea of heritable effects of use and disuse as a supplementary mechanism. Darwin subsequently set out his concept of pangenesis in

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4898-644: The previous generation. However, the characterization of these findings as Lamarckism has been disputed. Epigenetic inheritance has been argued by scientists including Eva Jablonka and Marion J. Lamb to be Lamarckian. Epigenetics is based on hereditary elements other than genes that pass into the germ cells. These include methylation patterns in DNA and chromatin marks on histone proteins, both involved in gene regulation . These marks are responsive to environmental stimuli, differentially affect gene expression, and are adaptive, with phenotypic effects that persist for some generations. The mechanism may also enable

4977-532: The problem of the origin of species of the view that acquired characters were inherited and in showing that evolution could be inferred logically from the accepted biological hypotheses. He would doubtless have been greatly astonished to learn that a belief in the inheritance of acquired characters is now labeled "Lamarckian," although he would almost certainly have felt flattered if evolution itself had been so designated. Peter Medawar wrote regarding Lamarckism, "very few professional biologists believe that anything of

5056-688: The production and classes of ideas, and seeks to explain the causes and mechanisms of sleep, reverie, vertigo, and drunkenness. He then discusses anatomy, especially the operation of the circulatory system and various glands. Chapter 29, "The Retrograde Motions of the Absorbent Vessels," is Erasmus Darwin's translation of his late son Charles Darwin 's dissertation. These anatomical chapters are followed by four chapters on diseases, which draws on his classification of four types of motion to identify four types of diseases: those of irritation, of sensation, of volition, and of association. Two chapters, "Of

5135-480: The qualities or attributes that define an entity as an organism, has evolved socially as groups of simpler units (from cells upwards) came to cooperate without conflicts. They propose that cooperation should be used as the "defining trait" of an organism. This would treat many types of collaboration, including the fungus / alga partnership of different species in a lichen , or the permanent sexual partnership of an anglerfish , as an organism. The term "organism" (from

5214-406: The rapidly increasing evidence for natural selection, Lamarck has never ceased to have loyal followers.... There is indeed a strong emotional appeal in the thought that every little effort an animal puts forth is somehow transmitted to his progeny. According to Ernst Mayr, any Lamarckian theory involving the inheritance of acquired characters has been refuted as " DNA does not directly participate in

5293-477: The reality of evolution but doubted whether natural selection was the main evolutionary mechanism. Among the most popular alternatives were theories involving the inheritance of characteristics acquired during an organism's lifetime. Scientists who felt that such Lamarckian mechanisms were the key to evolution were called neo-Lamarckians. They included the British botanist George Henslow (1835–1925), who studied

5372-612: The same argument, or a criterion of high co-operation and low conflict, would include some mutualistic (e.g. lichens) and sexual partnerships (e.g. anglerfish ) as organisms. If group selection occurs, then a group could be viewed as a superorganism , optimized by group adaptation . Another view is that attributes like autonomy, genetic homogeneity and genetic uniqueness should be examined separately rather than demanding that an organism should have all of them; if so, there are multiple dimensions to biological individuality, resulting in several types of organism. A unicellular organism

5451-490: The same. Zirkle pointed out that stories involving the idea of inheritance of acquired characteristics appear numerous times in ancient mythology and the Bible and persisted through to Rudyard Kipling 's Just So Stories . The idea is mentioned in 18th century sources such as Diderot 's D'Alembert's Dream . Erasmus Darwin's Zoonomia (c. 1795) suggested that warm-blooded animals develop from "one living filament... with

5530-551: The sympathetic theory of fevers, to distinguish it from the mechanic theory of Boerhaave, the spasmodic theory of Hoffman and of Cullen, and the putrid theory of Pringle." He then provides a systematic listing of "materia medica", or "substances, which may contribute to the restoration of health." These substances are divided into seven classes of their own: nutrientia, incitantia, secernentia, sorbentia, invertentia, revertentia, and torpentia. The historian of science Stephen Jay Gould says that " Zoonomia owes its modern reputation to

5609-458: The tails off mice does not seem to meet the qualifications of disuse, but rather falls in a category of accidental misuse... Lamarck's hypothesis has never been proven experimentally and there is no known mechanism to support the idea that somatic change, however acquired, can in some way induce a change in the germplasm. On the other hand it is difficult to disprove Lamarck's idea experimentally, and it seems that Weismann's experiment fails to provide

5688-434: The term "pan-environmentalism" for his evolutionary theory which he saw as a fusion of Darwinism with neo-Lamarckism. He held that heterochrony is a main mechanism for evolutionary change and that novelty in evolution can be generated by genetic assimilation . His views were criticized by Arthur M. Shapiro for providing no solid evidence for his theory. Shapiro noted that "Matsuda himself accepts too much at face value and

5767-452: The theory that what is inherited derives from the whole body of the parent, whereas Aristotle thought it impossible; but that all the same, Aristotle implicitly agreed to the inheritance of acquired characteristics, giving the example of the inheritance of a scar, or of blindness, though noting that children do not always resemble their parents. Zirkle recorded that Pliny the Elder thought much

5846-408: The vegetable living filament was originally different from that of each tribe of animals above described? And that the productive living filament of each of those tribes was different originally from the other? Or, as the earth and ocean were probably peopled with vegetable productions long before the existence of animals...shall we conjecture that one and the same kind of living filament is and has been

5925-459: Was co-evolution of viruses and host cells. If host cells did not exist, viral evolution would be impossible. As for reproduction, viruses rely on hosts' machinery to replicate. The discovery of viruses with genes coding for energy metabolism and protein synthesis fuelled the debate about whether viruses are living organisms, but the genes have a cellular origin. Most likely, they were acquired through horizontal gene transfer from viral hosts. There

6004-424: Was necessary to cause variation in the hereditary material. The identification of Lamarckism with the inheritance of acquired characteristics is regarded by evolutionary biologists including Ghiselin as a falsified artifact of the subsequent history of evolutionary thought, repeated in textbooks without analysis, and wrongly contrasted with a falsified picture of Darwin's thinking. Ghiselin notes that "Darwin accepted

6083-580: Was neither the first nor the most distinguished biologist to believe in the inheritance of acquired characters. He merely endorsed a belief which had been generally accepted for at least 2,200 years before his time and used it to explain how evolution could have taken place. The inheritance of acquired characters had been accepted previously by Hippocrates , Aristotle , Galen , Roger Bacon , Jerome Cardan , Levinus Lemnius , John Ray , Michael Adanson , Jo. Fried. Blumenbach and Erasmus Darwin among others. Zirkle noted that Hippocrates described pangenesis ,

6162-462: Was similar to Lamarck's ideas on evolution . Darwin advocated a hypothesis of pangenesis in the third edition of Zoonomia . English Romantic poet William Wordsworth used Darwin's Zoonomia as a source for "Goody Blake and Harry Gill", a poem published in the Lyrical Ballads (1798). Zoonomia is the project name for a genomic sequence alignment effort, attempting to explore

6241-487: Was to argue that the acquired traits were heritable. He gave as an imagined illustration the idea that when giraffes stretch their necks to reach leaves high in trees, they would strengthen and gradually lengthen their necks. These giraffes would then have offspring with slightly longer necks. In the same way, he argued, a blacksmith , through his work, strengthens the muscles in his arms, and thus his sons would have similar muscular development when they mature. Lamarck stated

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