Journal of Entomology and Zoology Studies 2017; 5(3): 06-12 E-ISSN: 2320-7078 P-ISSN: 2349-6800 JEZS 2017; 5(3): 06-12 Punctuated equilibrium theory represents shifting © 2017 JEZS balance theory (of macro and quantum evolution) Received: 02-03-2017 Accepted: 04-04-2017 and invalid Darwin’s theory Md. Abdul Ahad Department of Entomology, Faculty of Agriculture, Hajee Md. Abdul Ahad Mohammad Danesh Science & Technology University, DOI: https://doi.org/10.22271/j.ento.2017.v5.i3a.1778 Dinajpur-5200, Bangladesh Abstract The objectives of this article are that to prove punctuated equilibrium theory represents shifting balance theory and these two theories declared invalid Darwin’s theory and Neo-Darwinian theory and those are true fact: Because all features of both theories are same- i) Genetic drift play the key role of both theories. ii) Both theories advocated evolution progresses rapidly in a small and isolated population with rapid evolution after long period of stasis without the help of Darwin’s theory. iii) Both theories advocated allopatric speciation, macroevolution, quantum evolution and species selection. iv) Fossil is the only evidence of both theories. Additionally, those theories declared invalid Darwin’s theory and Neo-Darwinian theory. As a result, if anyone proves that genetic drift unable to produce new species or rejected shifting balance theory and fossil does not support macroevolution but support gradual evolution; then punctuated equilibrium theory even allopatric speciation theory would be invalid automatically. Keywords: Macroevolution and quantum evolution, abrupt change, small population, evolutionary biology 1. Introduction Evolution suggests that life arose by natural process from non-living materials and achieved its present diversity including man [1]. Darwin defines evolution as descent with modification [2] through natural selection from a few common ancestors . However, the entire evolutionary flowchart may be as follows: unicellular organism/bacterium → invertebrate→ lung fish→ amphibian→ reptile→ placental mammal→ higher mammal→ human [3, 4, and 5]. However, from time to time, various theories have been proposed to explain the mechanisms of evolution. These theories are: Lamarckism, Darwinism, mutation theory, shifting balance theory, synthetic theory/Neo-Darwinism, sociobiology and punctuated equilibrium [6]. [7] [8] Correspondence Fig 1: Adaptive landscape . Fig 2: Adaptive landscape . Md. Abdul Ahad Department of Entomology, Sewall Wright (an American geneticist; Professor, Chicago University) invented shifting Faculty of Agriculture, Hajee balance theory of macroevolution [9]. In 1932, Wright provided its diagram as ‘adaptive Mohammad Danesh Science & landscape model’ (Fig.1 and 2) [7]. In 1982, Wright again published an article entitled “Shifting Technology University, balance theory and macroevolution” and declared “From time to time, however, a species is Dinajpur-5200, Bangladesh represented with vacant niches. This precipitates evolutionary change of a different order of ~ 6 ~ Journal of Entomology and Zoology Studies magnitude, those that constitute macroevolution [10]. i) In fact, it is so weak that the change could easily be Nonetheless, the shifting balance theory of evolution is accomplished by genetic drift, even in large populations (the perhaps the most well-known of Wright’s contributions to smallest population size for which such change could occur evolutionary biology and also helped many biologists to think by drift at least 5% of the time is only 10,000) [15]. ii) about the evolutionary process in real populations [11]. This Evolutionary biologists must now take seriously the theory is regarded by many as a cornerstone of modern suggestion that many, if not most, changes in structural genes evolutionary thought [12]. This theory is a very complex drift to fixation in the neutral mode, do not affect phenotypes, systems model that was never developed beyond that of a and are therefore both unrelated and indistinguishable to metaphor of evolutionary biology [13]. However, the key force Darwinian processes [15]. and the evidences of this theory are not so clear and about its So, Gould and Eldredge used genetics drift as key force of literature are scanty. punctuated equilibrium theory. So, genetics drift as key force In 1972 and 1977 two American paleontologists, Stephen J. of both punctuated equilibrium theory and shifting balance Gould (Professor, Harvard University) and Niles Eldredge theory i.e. genetics drift represents punctuated equilibrium (Professor, Natural History Museum) developed the theory and the shifting balance theory. punctuated equilibrium theory [14, 15 and 16]. They declared that In addition, Gould and Eldredge exploited “Wright’s the punctuated equilibrium theory is a general theory, valid theory/Wright” 2 times in 1972 [14], “Wright’s rule/ Wright’s throughout the biological science [15]; even the 20th century is analogy/Wright’s grand analogy” 10 times in 1977 [15], for the punctuated equilibrium [17]. The punctuated “Wright break/Wright” 10 times in 1980 [16] to support their equilibrium has brought much excitement to modern theory punctuated equilibrium. For example (in Eldredge and evolutionary biology [18]. Gould and Eldredge frequently used Gould’s Languages): i) The species selection depend upon the the terms the “genetic drift” and “Wright’s rule”. But what validity of "Wright's rule"—the claim that speciation is they meant Wright’s rule? Are they mean it shifting balance essentially random with respect to the direction of a macro theory? What is the key element and evidences of their evolutionary trend [15]. ii) Test Wright's Rule as a precondition theory? Is there any relationship with genetic drift/ the for species selection [15]. iii) Wright's Rule also requires that shifting balance theory? Those are not so clear. So, to find out speciation be common in order to provide enough raw those are necessary. This article would be very helpful to the materials for species selection [15]. iv) “All movement from student of evolutionary biology and also who dealing with micro to macroevolution must be translated through the level evolution. So, to work on the objective is essential. of species by Wright's grand analogy, not merely extrapolated up in continuity” [15]. 2. Genetic drift plays the key role of both shifting balance Here Gould and Eldredge utilized the “shifting balance theory and punctuated equilibrium theory theory” as the “Wright’s rule”; Gould and Eldredge admitted The following statements proved that genetic drift plays the directly: key role of both shifting balance theory and punctuated “We choose Wright's name for our designation because he equilibrium theory: (1967, p. 121) explicitly suggested that speciation might by a) Wright exploited drift/drifting 8 times in 1931 [9]; 10 times truly stochastic with respect to the direction of evolutionary in 1982 [10] for the rapid evolution of new species in small and trends. But we wish to record our debt to Ernst Mayr who has isolated populations. For example (in Wright’s words): i) so forcefully and consistently supported the idea that Merely by chance one or the other of the allelomorphs may be speciation is the stuff of evolutionary change” [15]. expected to increase its frequency in a given generation and in The above statements of Gould and Eldredge confirmed that time the proportions may drift a long way from the original Gould and Eldredge used shifting balance theory as the values [9]. ii) The random drift from causes other than “Wright’s rule” in punctuated equilibrium, which again accidents of sampling (referred to in 1931) was treated proves that genetic drift represent shifting balance theory, the mathematically in 1948. The last phases of the shifting Wright’s rule, the punctuated equilibrium and vice-versa. balance process, the spreading of a favorable interaction [10]. Consequently, if one proves genetic drift unable to produce Moreover, in 1982, Wright wrote an article entitled ‘the new species or rejected shifting balance theory then the shifting balance theory and macroevolution’. In this article punctuated equilibrium would be invalid. Wright declared: “Because of persistent misunderstandings, the shifting balance theory, which was proposed half a 3. Both shifting balance theory and punctuated century ago (in 1931), primarily in connection with equilibrium advocated evolution progresses rapidly in a microevolution, is reviewed here at some length before small and isolated population: discussing its relation to macroevolution” [10]. The same a) Documents from Wright’s article about use of small opinion is also given by the editor of the journal “Annual and isolated populations for evolution progresses rapidly review of genetics” [10]. In 1931, Wright exploited isolation 14 times and also small This declaration of Wright and the editor confirmed that the population 14 times [9]; in 1982 he exploited small/small genetic drift means the shifting balance theory. Consequently, colonies 10 times for the macroevolution of new species in if one proves genetic drift unable to produce new species then small and isolated populations through genetic drift. For the shifting balance theory would be invalid. examples (in Wright’s words): i) Complete separation of the In addition, the shifting balance theory is based on the role of species into large subspecies should be followed by rather genetic drift [19]. Genetic drift plays a crucial role in the shift slow more or less closely