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Don Batten
Translation: Evgeny Galchenko, ed. Alexey Kalko ()
Translated with permission from creation.com

Comparative characteristics of phyletic gradualism and punctuated equilibrium: punctuated equilibrium is achieved due to rapid and abrupt changes in morphology.

The article discusses the concept of punctuated equilibrium (PE). The development of the idea since its proposal by Stephen Gould and Nils Eldridge, as well as some contradictions, is traced. PR consists of two aspects:

1. observations - that the fossil record is characterized by

• (a) the sudden appearance of species, and
• (b) stasis, or the absence of significant change throughout the diversity of species in the fossil record; and also

Gould and Eldridge stated that the sudden appearance of species could be explained by the fact that transitions occurred quickly (in a geological sense), in small isolated populations, and thus the chances of preserving the remains of transitional species were very small. They stated that this theory follows from biology, but there is no empirical biological basis for such speciation events. It seems that this "mechanism" was accepted because it "explained" their observations of fossils (both scientists are paleontologists). Gould gave rise to the development of ideas of macromutational changes to explain large transitions and the idea that rapid speciation of PR is a type of evolution called “promising monsters.” Although Gould and Eldridge denied that they meant it.

The PR debate has brought attention to the fact that stasis is a major problem for the theory of evolution (how can one believe in evolution or change when fossil evidence shows stasis and no change?). Recognizing the reality of sudden emergence and stasis confirms what creationists have been saying since Darwin - that the facts are consistent with special creation combined with the effects of a global Flood. Wise's idea of ​​“punctuated equilibrium, creationist style” will also be considered in this context.

The concept of punctuated equilibrium

Niels Eldridge (currently curator of invertebrates at the American Museum of Natural History in New York) and Stephen Jay Gould (professor of geology at the Museum of Comparative Zoology at Harvard University) originated the idea of ​​“punctuated equilibrium” at a symposium on paleontological models in 1970 at the University of Chicago. The study was published in 1972. The idea was born from their recognition of stasis (lack of gradual change) in fossil remains. In other words, species remained apparently stable throughout their “life history,” showing no significant change from the time they appeared in the fossil record to the time they went extinct. Eldredge, in particular, spent considerable effort searching for evidence of gradual evolutionary changes linking trilobite species in the Devonian layer of the United States and Canada, but without success. For example, according to neo-Darwinian theory, the number of lenses in the eye should gradually change from one species of trilobite to another, but this is not observed. Little change occurred over long periods of time, and "species" seemed to simply come and go.

Eldridge and Gould, as paleontologists, recognized that this pattern of little change over time (according to the evolutionist interpretation of fossils), and the lack of evidence for gradual transformation from one species to another, was generally characteristic of the fossil record. This was not a unique feature of Devonian trilobites. New species “appear” in rock layers without any evidence of gradual transitions from other forms. The fossil record is characterized by long periods of stasis, or equilibrium, in which species are clearly identified and remain stable, and these periods are interrupted by the occasional sudden, or “rapid,” appearance of new species. Hence the name: “punctuated equilibrium.”

Paleontologists usually justified gaps in the fossil record (lack of evidence of gradual changes and phylogeny) by insufficient knowledge of it, as Darwin also said. Eldridge and Gould recognized the fact that gaps are typical in the fossil record. Also, paleontologists ignored stasis, considering it a “lack of data” of no interest. Gould and Eldridge recognized that "stasis is data." Gould and Eldredge considered species to be discrete units, with a definable beginning (that is, the emergence of a species) and an end (extinction), which contradicts the neo-Darwinian idea of ​​constantly transforming species without clear boundaries. Eldridge and Gould spoke of species as "distinct entities." “Speciation” is to species what mutation is to individuals. Speciation is perceived as something random, just like mutation for an individual. New species are subject to natural selection, which eliminates those that are not viable. The original publication begins with a philosophical address about the reluctance of most evolutionists to acknowledge the lack of fossil evidence for gradualism. That is, the predominance of theory over “facts”. Eldridge and Gould admit, as do other commentators on the scientific method, that facts "speak" only when they fit the theory; otherwise, arguments are sought to ignore them. They said they were proposing a new theory that would reconcile the evidence of stasis and sudden emergence of species in the fossil record with an evolutionary (i.e., naturalistic) paradigm. Previously, stasis was ignored, and gaps were explained by incomplete knowledge.

On the one hand, punctuated equilibrium (PE) is simply a description of the fossil record (assuming a geological time scale, of course). On the other hand, this is an evolutionary process, which, according to Eldridge and Gould, can explain the situation with fossil remains. They stated that significant changes occurred in small isolated populations distant from the main populations (allopatric speciation by peripheral isolation). And that these changes occurred quite quickly (in a geological sense). This is a proposed mechanism to explain stasis and gaps in the fossil record. They wrote:

"Because speciation occurs rapidly in small populations occupying small areas far from the center of their ancestral range, finding such an event in the fossil record should be rare."

Another proponent of PR, Stephen Stanley, stated that

“Gradual evolutionary change through natural selection acts so slowly within established species that it cannot explain the main features of evolution”

agreeing, therefore, that the changes giving rise to new species occurred relatively quickly.

Punctuated equilibria or punctuated equilibrium

In their 1972 publication, Eldridge and Gould used the term “punctuated equilibria” to refer to their concept. Eldredge used the term in his writings, while Gould spoke of "punctuated equilibrium" (compare, for example, the article titles in footnotes 9 and 28). Their updated 1993 publication uses the term punctuated equilibrium, so apparently that's what the term has become.

Origin of the idea of ​​punctuated equilibrium

Other researchers also recognized that the fossil record showed no evidence of gradual transition between taxa. For example, in 1940, Richard Goldschmidt argued that transitions had to happen quickly, in jumps, which is why transitional forms could not fossilize, since they never existed. Goldschmidt's ideas were ridiculed by most evolutionists in the 1940s and 1950s, since paleontologists still believed that fossils of transitional forms would be found in future research. Moreover, there was no biological basis for understanding how new species could arise as quickly as Goldschmidt assumed.

The basic "mechanism" of speciation proposed by Eldridge and Gould was borrowed from other scientists. The concept of allopatric (geographic) speciation has previously been recognized as a mechanism of evolutionary change, albeit acting gradually. In particular, this idea was developed by Mayr. Eldredge recognized that the history of the idea of ​​allopatric speciation can be traced back to pre-Darwinian biology. Eldridge and Gould made one controversial statement, namely that:

"Most evolutionary changes in morphology occur over a short period of time relative to the overall lifespan of the species"

and argued that this is a logical conclusion from the theory of allopatric speciation in peripherally isolated populations. Although they admitted that

“No new theory of evolutionary mechanisms can be developed on the basis of paleontological data,”

one might suspect that the idea of ​​rapid speciation arose from their reading of the fossil record rather than from any new understanding of allopathic speciation. Even the idea of ​​rapid speciation was not so new. In addition to Goldschmidt, in the 1960s, Soviet specialists proposed that change is usually concentrated in rapid speciation events, and that species apparently remain stable after their formation.

Punctuated equilibrium, creationist style

Curt Wise, a *creation paleontologist, has proposed an alternative explanation for the sudden emergence of species and stasis that characterizes the fossil record. Gould and Eldredge relied on the generally accepted interpretation of the stratigraphic column, which holds that it is the result of long-term sedimentation of rocks, with each layer containing examples of life forms on earth that existed at that time. In this case, the fossil evidence resembles a frame-by-frame replay of a newsreel about life on earth (albeit with varying periods between frames). Wise showed that if most of the stratigraphic record is the result of a single catastrophe such as the Great Flood and its aftermath, then this could explain the situation of sudden appearance of species and stasis in the fossil record. A sample of each species would be instantly imprinted by such an event, and thus the species would exhibit static properties. Rare exceptions to stasis, namely successive vertical gradients of change, such as increasing size as one moves upward (a common observation called Cope's Law), can be explained by sorting processes. Also, some patterns may reflect initial geographic or altitudinal gradients in morphology. In addition, vertical gradients in shape could be the result of actual transitions during the catastrophe, but this could only happen with species that were resistant to the conditions of the catastrophe and with a lifespan of one generation significantly shorter than the duration of the catastrophe itself (one year of the Flood). Wise suggested that the exception to stasis could be marine organisms with short generation times. The best example of an exception to stasis known to Wise was the Permian foraminifera, a marine organism with a short lifespan of one generation, consistent with the catastrophic Flood model.

Wise wrote:

“The rarity of exceptions to punctuated equilibrium sensu stricto[i.e., stasis and sudden emergence of species] indicates that the model of catastrophic sedimentation of the earth's rocks can be considered a mechanism for explaining paleontological observations of the theory of punctuated equilibrium."

Gould was particularly irritated by creationists exploiting his admissions about the lack of fossil evidence for phylogeny and his sympathy for speciation through Goldschmidt's "promising monsters." Creationists have widely cited statements Gould made in the 1970s. Judging by a recent publication, Gould appears to be "back to square one." He abandoned his earlier position that there were no clear examples of transitional fossil sequences, be they interspecies transitions or transitions between the basic principles of the structure of organisms, and turned to the story of the “walking whale” as evidence of the transformation of one species into another. The evidence for this transition is weak, but Gould accepts the dreamy description of Ambulocetus without critical reflection Ambulocetus natans who walked and swam, presented by Thewissen etc. In the 1970s, other scientists put forward a number of examples of gradualistic changes in fossils to refute the PR theory (that is, in favor of gradualism). Gould and Eldridge denied these claims, arguing

“that practically none of the examples presented to refute our model can be a confirmation of phyletic gradualism.”

Proposed examples of sequences of transitions and intermediate forms met with sharp criticism from Gould in the 1970s, but he now describes a rather inconclusive history of whale evolution as

"the most beautiful series of transitional fossil forms that an evolutionist could dream of finding."

One need only read Gould's work to see how uncritically he accepts this whole story. Also visible in the work is Gould's almost obsessive preoccupation with opposing creationist claims that the fossil record does not demonstrate evolution and that there are no indisputable transitional forms - a claim that Gould himself made repeatedly in the 1970s, when he promoted stasis and rapid change. and when, apparently, creationists didn't bother him so much.

In 1982, Gould distanced himself from the "promising monsters":

“Punctuated equilibrium is not a theory of macromutation, it is not a theory about any genetic process.”

Gould admits that he supported

"certain forms of macromutation theory... but not in the context of punctuated equilibrium."

"This book is my version of the history of punctuated equilibria" ... (emphasis added),

indicating his desire to distance himself from other versions. Regarding the lack of gradual change in the fossil record, Eldridge was less dogmatic than Gould was in the 1970s. Eldridge wrote:

“gradualistic changes remain theoretically possible” and “... some gradualistic changes exist... But, in fact, it does not tell us about the emergence of something truly new. It doesn’t actually take us anywhere.”

He noted the importance of allopatric (geographic) speciation in explaining gaps in the fossil record. That is, Eldredge believed that major changes occur somewhere away from the main population, in small isolated populations, and therefore they do not (usually) persist, especially in the habitat of the parent species. He emphasized the theory of peripatric speciation (a version of allopatric speciation with peripheral isolation).

Eldredge objected to the association of PR with the idea of ​​"promising monsters":

"The claim that punctuated equilibria represent the resurrection of Goldschmidt's 'macromutations' and 'promising monsters' remains the most serious and unfortunate misinterpretation of our ideas."

He also wrote that

“The most common misconception about “punctuated equilibria” is that Gould and I have proposed a saltationist model of change occurring instantaneously, supposedly as a result of sudden mutations with large-scale consequences (macromutations à la Richard Goldschmidt)….”

Eldridge said:

“The changes chosen are usually rapid. But fast in context millions years". (emphasis added).

Twenty-one years later, while reviewing their theory of PR, Gould and Eldredge had lost ground to the point of proposing PR as an “addendum to phyletic gradualism.” This is quite a concession compared to the boldness of their statements in 1972, and especially Gould's statements in 1980, as Levinton noted in his response to the review.

Is evolution by punctuated equilibrium a biological absurdity?

Gould and Eldridge write:

"Stasis, being obvious and observable in almost all cases (while rapid transitions are usually, though not always, elusive), becomes the main empirical basis for the study of punctuated equilibrium"

“...stasis, inevitably interpreted as the absence of evolution, has always been perceived as something insignificant. However, it is very strange to define the most common of all paleontological phenomena as something not worthy of interest or attention!

What are Gould and Eldredge essentially saying? What is PR? In fact, PR is the supposed way of evolution. What is evolution? Isn't it change? PR should be a way for change to flow, but its confirmation is stasis. But what is “stasis”? Isn't this no change? In this case, the absence of changes (stasis) is confirmation of changes (evolution through PR)!

Ironically, the tautological nature of "survival of the fittest" as the definition of natural selection in neo-Darwinian evolution is perfectly preserved in Gould and Eldridge's extrapolation of this concept to species:

"The geological record records episodes of high mortality during which groups prone to extinction are likely to disappear, while groups resistant to extinction inherit life."

However, PR is less accepted among evolutionary biologists or geneticists. For example, Maynard Smith's general attitude is that

“...we can forget about new paradigms and the death of neo-Darwinism.”

About species selection He said:

"The idea never made much sense anyway."

Apparently even opponents of PR have accepted the concept of stasis and even short periods of rapid change, but they reject the anti-Neo-Darwinian idea of ​​non-adaptive random emergence of new species and species selection as a means of macroevolution. John Maynard Smith, for example, said:

“However, it is quite possible to accept the claim that the typical pattern of change is long periods of stasis interrupted by short periods of rapid change without accepting the ideas of non-adaptive change, species selection and the separation of macro- and microevolution. This question must be addressed by paleontologists.”

Interestingly, in their 1993 review paper, Gould and Eldredge define macroevolution as the "culling of species" and argue, somewhat blandly, that

"Darwinian extrapolation cannot fully explain large-scale changes in the history of life."

But what explains the massive changes? They again state that

“punctuated equilibrium was never a saltationist theory [a macromutation theory].”

They do not offer a biological basis for large-scale changes. Really,

“endless discontent, this time justified, has focused on claims that speciation causes significant morphological changes, for no evidence for this has been found”

The punctuated equilibrium hypothesis was presented in four key publications (Eldredge and Gould, 1972; Gould and Eldredge, 1977; Stanley, 1975, 1979*). This hypothesis contains the following main provisions: 1) since the time of Darwin, most evolutionists, including supporters of the synthetic theory, consider evolution as a state of slow and uniform change, as a case of “phyletic gradualism”; 2) true macroevolutionary changes are bursty in nature, so that long periods of constancy (or “stagnation”) alternate with short episodes of rapid change; 3) episodes of significant change coincide with speciation events. This thesis has been formulated for the first time.

The concept of punctuated equilibrium caused great controversy immediately after its first publications in the seventies. When critically examining this problem, two approaches are possible. One can simply accept the punctuated equilibrium model and discuss the pros and cons, as many authors do, or one can examine it historically and scientifically to see how original it is. We will take this second approach here (for more detailed criticism see Grant, 1982, 1983; Simpson, 1983; Gingerich, 1984; Brown, 1987*).

Despite the fact that the views of Eldredge and Gould, on the one hand, and Stanley, on the other, converge on the main theoretical points, their works differ markedly in scientific style and will be considered separately. Stanley's (1979*) major work on punctuated equilibrium is well documented in both the evidence and the evolutionary literature and deserves serious attention.

Eldredge and Gould (1972; Gould and Eldredge, 1977*), in contrast, have been remarkably consistent in ignoring the foundational literature on the subject at hand. Their 1972 paper was written under the influence of Mayr and Darwin. The literature on which Based on their 1977 work, it is somewhat more complete, but still woefully insufficient.

The first result of this inadequate literature review is a straw man, phyletic gradualism. None of the major evolutionists of recent years has advocated phyletic gradualism in its pure form. In contrast, the synthetic theory of evolution constantly discusses the idea of ​​occasional episodes of rapid and abrupt evolutionary change. This idea was considered before 1972 by Wright (1931, 1949, 1960*), Simpson (1944, 1953*), Rensch (1947, 1960*), Mayr (1954, 1963, 1970* ), Carson (1959, 1971*), Lewis (1962*), Grant (1963, 1971*) and other authors. None of this early work, with the exception of the contribution of Mayr, Eldredge and Gould, was given due attention in their papers in 1972 and 1977, and many were simply neglected.

Simpson's concept of quantum evolution is not mentioned at all in the 1972 paper, but is mentioned in passing in the 1977 paper. Gould (1982a*) later justified this omission on the grounds that quantum evolution is a mode of phyletic evolution, whereas punctuated equilibrium is the result of speciation. To support his statement, Gould quotes from Simpson (1953*). He does not, however, mention Simpson's statement on the same page that quantum evolution can also occur through speciation.

Although Simpson accepted a connection between speciation and quantum evolution, he did not explore this connection. However, this was done by me a few years later (Grant, 1963*) in a paper that Eldredge and Gould also ignored.

Here I have focused on numerous and serious literary omissions in Eldredge and Gould's papers published in 1972 and 1977. It should be noted that these omissions were not adequately addressed in later articles by these authors (Gould, Eldredge, 1986*).

So what's new about the punctuated equilibrium hypothesis? Nothing. There are no new ideas in this hypothesis that were not expressed in a clear and distinct form in the evolutionary literature published before 1972.

Indeed, the punctuated equilibrium model is not as good as the earlier interpretation of this problem. This model is scholastic in nature. She tries to reduce all or almost all paleontological series to two opposite states: stagnation and intermittent shifts. But in fact, the evolutionary history of real groups shows a wide range of evolutionary rates or mixtures of anagenetic and cladogenetic modes. The quantum evolution model is an open structure that can accommodate all the diversity of truly existing macroevolutionary processes.

Punctuated-Equilibrium Theory

In this theoretical approach, the process policymaking is seen as an incremental process in which major policy changes occur very rarely, but in short periods of time. The approach was developed by Baumgartner and Jones (1993), and its main idea was based on the theory of evolutionary biology by Eldridge and S.D. Gould. The idea was that most of the time species change little, remaining in a state of so-called “stasis,” and evolutionary changes usually occur quickly (relative to the period of this state). PET in political science uses this idea and argues that the process policymaking most of the time it proceeds smoothly, but sometimes significant shifts occur. Respectively, PET tries to find an answer to such a research question: why a political system, characterized by the same set of institutions and an identical organizational structure, changes very slowly at some points in time, and in some cases is subject to radical shifts. (Sabatier 2006, p.156). In this regard, another question arises: what causes these shifts against the background of long-term incremental changes?

The focus of this theoretical approach is on political institutions and bounded rationality in decision making. Therefore, the incremental nature of the process is explained by the influence of interests entrenched through routines, a special institutional structure and the bounded rationality of actors who are unable to appreciate the fullness and complexity of a political issue at a particular moment in time (Baumgartner and Jones 1993).

If periods of stability (or “stasis”) are explained by categories familiar to political science such as institutions, then how does this theory reveal the causes of change? In this regard, the concept of bounded rationality and the role of information in the process are very important. policymaking. Jones argues that changes in decision making do not arise from random changes in preferences or inherent irrationality in humans, but from attentional shifts(Jones 1994). This approach uses findings from psychological research: according to the work of G. Simon, human senses can perceive information in parallel to each other, but a person’s attention can only be focused on one or two things at a particular moment in time (Simon 1977, 1983). Reality can be complex, changeable and multifaceted, but it is impossible to reconcile competing concepts and points of view into a single picture of the world: the human brain needs to fix attention on one. Changing the object of attention, in turn, can lead to changing set of preferences. In other words, changes in preferences are not random, but are the result of a shift in attention.

Organizations can also be considered from the point of view of this theory, because they are architecturally similar to human thought, being created as a result of its work (Jones 2001). Therefore, these arguments can also be applied to political organizations to explain the process policymaking. Jones writes about the importance of information in politics: “Information is viewed as inherently ambiguous, so that there is a very important role for leadership and policy entrepreneurship in the framing of issues. . . . The manipulation of information plays a key role in forcing governmental attention to problems.” (Jones 1994, p. 23).

The theory places the greatest emphasis on two interrelated elements of the political process: the definition of political issues ( issue definition) and agenda setting ( agenda-setting). According to the authors of the theory, it is the identification of political issues and their placement on the agenda that plays a key role in revising the political course. “Punctuated dynamics may be a direct consequence of disproportionate information processing, in which people and organizations they inhabit struggle to prioritize informational signals from the environment within a particular institutional frame or structure” (Jones and Baumgartner 2005). In other words, the approach argues that the process of abrupt changes in decision-making observed in political systems may be the result of the system's inability to prioritize different dimensions of the same problem. Because of this, the emergence of a new dimension on the agenda may change the structure of preferences of decision makers: “When a policy shifts to the macropolitical institutions for serial processing, it generally does so in an environment of changing issue definitions and heightened attentiveness by the media and broader publics” (Jones 1994, p. 185).

Related to this is the question of how political issues are distributed within decision-making institutions. The theory links the distribution of information within institutions with the so-called “parallel processing of political issues.” This concept refers to a situation where, within the same decision-making body (for example, parliament), different bureaucratic organizations, such as committees, consider the same issue, but from different perspectives. These positions will be determined by the specifics of the work of these bodies and their history. Therefore, due to the existence of the phenomenon of bounded rationality, the decision-making body will be forced to consider a political problem from only one side (Sabatier, p. 157). Reframing an issue by one of the rivals can change the preferences of the decision-making body without changing the priorities in positioning the given issue, resulting in a sharp change in political course.

Here are a couple of works in which this theoretical approach was used, the following can be highlighted: Sheingate used PET to analyze the agricultural policy process in the European Union (Sheingate 2000). The approach has been used to explain long-term changes in US federal government budgets (Jones, Baumgartner and True 1998). In addition, the theory has attracted the attention of researchers of historical institutionalism.

PICUTTEN EQUILIBRIUM PICUTTEN EQUILIBRIUM

an evolutionary concept directed against the idea of ​​the slow and continuous nature of speciation and the principle of the unity of the mechanisms of micro- and macroevolution. Proposed by S. Gould and N. Eldridge in 1972. Proponents of the concept believe that the process of species formation occurs in short geological periods. time and is replaced by long, stabilization phases. As possible mechanisms of speciation, supporters of P. r. are called mutations of regulatory genes leading to, therefore, phenotypic. effect due to ontogenetic shifts. processes, genetic drift and rapid genetic transformations. structures of peripheral isolates. Speciation is essentially viewed as a non-adaptive process. The selection of randomly occurring species is considered to be specific. factor of macroevolution. Argumentation of supporters of the concept of P. r. based on ch. arr. based on paleontological data. chronicle that does not reflect the details of the gradual speciation. Long periods of stabilization of taxa can be explained by the action of stabilizing selection, preserving highly adaptive forms and characters. Therefore, many scientists who do not accept the concept of P. r. emphasize that paleontology. data on high morphological stability. signs are insufficient to conclude that the species has stabilized.

.(Source: “Biological Encyclopedic Dictionary.” Editor-in-chief M. S. Gilyarov; Editorial Board: A. A. Babaev, G. G. Vinberg, G. A. Zavarzin and others - 2nd ed., corrected . - M.: Sov. Encyclopedia, 1986.)

See what “Punctuated Equilibrium” is in other dictionaries:

Punctuated equilibrium- * intermittent evolution * punctuated equilibrium concept of evolutionary development (), based on the postulate of alternating stages of rapid development of forms and almost complete conservatism, when there are no smooth transitions between these stages.… … Genetics. Encyclopedic Dictionary

Punctuated equilibria “punctuated equilibrium”. An evolutionary concept based on the postulate of alternating stages of rapid development of forms and almost complete conservatism (in the absence of smooth transitions between these stages);... ... Molecular biology and genetics. Explanatory dictionary.

Punctuated equilibrium- - in biology, the position is that evolution can be considered as periods of relative stability, sometimes interrupted by the spasmodic appearance of new biological species. See Darwinism, Creationism... Encyclopedic Dictionary of Psychology and Pedagogy

PICUTTEN EQUILIBRIUM- A model of evolution according to which new species develop quite quickly (in geological terms), rather than gradually, as described in the standard Darwinian model. This term means that evolution can be viewed as periods of relative... Explanatory dictionary of psychology

- (also modern evolutionary synthesis) modern evolutionary theory, which is a synthesis of various disciplines, primarily genetics and Darwinism. STE also relies on paleontology, systematics, molecular biology and others.... ... Wikipedia

Synthetic theory of evolution (STE) is a modern evolutionary theory, which is a synthesis of various disciplines, primarily genetics and Darwinism. STE also relies on paleontology, systematics, molecular biology and others. Contents... Wikipedia

EVOLUTION, BIOLOGICAL, the theory according to which a species undergoes a series of successive changes in order to survive and produce offspring under complex and frequently changing conditions, with a new species being the result of development and change... ... Scientific and technical encyclopedic dictionary

Comparative characteristics of the theories of phyletic gradualism (above) with the theory of punctuated equilibrium (below): punctuated equilibrium is achieved due to rapid changes in morphology ... Wikipedia

It originates in ancient philosophical systems, the ideas of which, in turn, were rooted in cosmological myths. The impetus for the recognition of evolution by the scientific community was the publication of Charles Darwin’s book “The Origin of Species by Natural Means... ... Wikipedia

Comparative characteristics of the theories of phyletic gradualism (above) with the theory of punctuated equilibrium (below): punctuated equilibrium is achieved due to rapid changes in morphology The theory of punctuated equilibrium is a theory in the field of ... ... Wikipedia

Any theories and hypotheses in biology receive a logical conclusion only when they interact with the basic principles of the theory of evolution. However, the ways they interact are very complex and have many facets. Sometimes they take the form of specific principles.

In Charles Darwin's theory, three principles can be distinguished.

Variability is an integral property of living things.

There is an internal contradiction in living nature: on the one hand, all types of organisms tend to reproduce exponentially, on the other hand, a small part of the offspring become mature individuals.

The principle of natural selection is the central core of Darwin's theory.

All subsequent evolutionary theories that recognize the principle of “natural selection” are called “neo-Darwinian”.

Synthetic theory of evolution

One of the directions in the development of Darwinism is the synthetic theory of evolution, created in the 30-40s. XX century (E. Mayr calls the creation of the synthetic theory 1936-1947). it combines modern biological concepts on the basis of Darwinism: genetic-ecological study of population structure, results of experimental and theoretical genetics, models of the struggle for existence and natural selection. Sometimes the synthetic theory is called the result of the fusion of Mendelism and Darwinism. The origins of the creation of synthetic theory are S.S. Chetverikov, R. Fisher, S. Wright, J. Haldane.

The synthetic theory of evolution serves as the basis of the entire system of modern evolutionary biology. The synthesis of genetics and evolutionary teaching became a qualitative leap in the development of both genetics and evolutionary theory. It marked the creation of a qualitatively new core of the system of biological cognition, and became evidence of the transition of biology from the classical to the modern, non-classical level of development.

The immediate prerequisites for the synthesis of genetics and the theory of evolution were: the chromosomal theory of heredity, biometric and mathematical approaches to the analysis of evolution, the Hardy-Weiberg law for an ideal population (which states that such a population strives to maintain the balance of gene concentration in the absence of factors changing it), the results of empirical studies of variability in natural populations, etc.

This theory is based on the idea that the elementary “cell” of evolution is not an organism or a species, but a population. It is the population that is the real integral system of interconnection of organisms that has all the conditions for self-development, primarily the ability of hereditary change in the succession of biological generations. The elementary unit of heredity is a gene (a section of a deoxyribonucleic acid molecule - DNA, responsible for the development of certain characteristics of the body). A hereditary change in a population in any particular direction is carried out under the influence of a number of evolutionary factors (changing the genotypic composition of the population): mutation process (supplying elementary evolutionary material), population waves (fluctuations in the population size in one direction or another from the average number of individuals included in it) , isolation, natural selection - a process that determines the likelihood of individuals reaching reproductive age. Natural selection is the leading evolutionary factor directing the evolutionary process.

The formation of the synthetic theory of evolution marked the transition to a population concept that replaced the organism-centric one, the beginning of overcoming the opposition between historical and structurally invariant “cuts” in the study of living things, the integration of biology based on Darwinism (in Russia - N.I. Vavilov, I.I. Shmalgauzen, A. N. Severtsov, who developed the doctrine of the main directions of the biological process - aromophosis and idioadaptation, etc.). this opened a qualitatively new stage in the development of biology - the transition to the creation of a unified system of biological knowledge that reproduces the laws of development and functioning of the organic world as a whole.

Punctuated equilibrium theory

The theory of punctuated equilibrium was developed by paleontologists N. Eldrege and S. Gould. In the process of speciation, they identified phases of prolonged stagnation, alternating with rapid, spasmodic periods of morphogenesis. The idea of ​​uneven rates of evolution itself is by no means new. Darwin also expressed thoughts about the relative short duration of the stage of transition from one species to another and the relatively long existence of “established species.”

The theory of nomogenesis was developed by L.S. Berg (1876 -1950). In the 20s XX century he put forward a number of objections to Charles Darwin's theory of evolution. his own theory of evolution is based on its original purposiveness. The main law of this theory is “autonomous orthogenesis”, acting centripetally and independently of the external environment. All living things, Berg believed, are valuable and are called upon to implement the idea of ​​good. He argued that science, philosophy and art are three equal aspects of human spiritual activity.

Other theories of evolution include the following.

Orthogenesis is a change in organisms in a given direction, forced by some internal force.

Inheritance of acquired characteristics is a process in which changes that occur in individual organisms become heritable and lead to permanent changes in their descendants.

Saltationism is the sudden emergence of new species as a result of large mutations. The concept has an anti-Darwinian orientation, created in 1860-1870. A. Sues and A. Kelliker. according to saltationism, the entire plan for the future development of life arose at the moment of its appearance, and all evolutionary events occur as a result of abrupt changes (saltation [Saltation is a leap, a spontaneous qualitative change in a system (for example, genes).]) of embryogenesis.

For concepts of evolution based on the idea that all development in the world is the implementation of predetermined goals, there is a common name teleogenesis [Teleology (in biology) is an idealistic doctrine according to which living organisms are purposefully created by a higher power, God.].

One can also note the approach of A.A. Lyubishchev (1890-1972), who comprehensively studied the triad of problems “system-evolution-form”. He considered the form (of an organism) to be a simple adaptation to environmental conditions, determined by the need to perform a specific function. As for systematics in evolution, its goal is to build a “natural system of organisms.” Lyubishchev proceeded from the fact that the position of an organism in such a system determines all its essential characteristics.