Eldredge, N. and Gould, S. (1972). Punctuated Equilibria: An Alternative to Phyletic Gradualism, chapter 5, pages 82--115. Freeman, Cooper and Co.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....exist to parallelize a genetic algorithm [2] However, most of these methods result only in a speed up of the algorithm without qualitative improvements to the problem solutions. To gain better problem solutions, we use the theory of punctuated equilibria to design a parallel genetic algorithm [7] [10]. A genetic algorithm with punctuated equilibria is a parallel genetic algorithm in which independent subpopulations of individuals with their own fitness functions evolve in isolation except for an exchange of individuals (migration) when a state of equilibrium throughout all the subpopulations ....

N. Eldredge and S. J. Gould, "Punctuated Equilibria: An Alternative to Phyletic Gradualism," Models of Paleobiology, T. J. M. Schopf, ed., San Francisco, CA: Freeman, Cooper and Co., pp. 82-115, 1972.

....the genetic algorithm produces solutions with equal or better routing characteristics than the previously best published results. Lienig (1997) presents a parallel genetic algorithm for the channel and switchblock routing problem. The problem is based on the theory of punctuated equilibria from [Eldrege and Gould (1972)] and [Cohoon et al. 1991) A genetic algorithm with punctuated equilibria is a parallel genetic algorithm in which independent subpopulations of individuals with their own tness functions evolve in isolation, except for an exchange of individuals (migration) when a state of equilibrium ....

Eldredge N. and Gould S.L. Punctuated equilibria: An Alternative to Phyletic Gradulism, Models of Paleobiology, Freeman, Cooper and Co., San Francisco, CA, 1997, pp. 82-115.

.... in which the population explores the current neutral layer alternating with rapid fitness increases when an individual discovers a transition point to a fitter neutral layer [11] This pattern of evolution reflects the phenomenon of punctuated equilibria observed in several biological populations [3]. The NK landscape model was initially developed to model the fitness landscapes resulting from systems with various levels of interaction between the components, for example a genotype with epistatic linkages between genes [8] By altering the level of epistatic interaction, it is possible to ....

Eldredge, N. & Gould, S. J., Punctuated equilibria: an alternative to phyletic gradualism. In T. J. M. Schopf (Ed.), Models in Paleobiology. pp. 82-115. San Francisco: Freeman, 1972.

....exist to parallelize a genetic algorithm [2] However, most of these methods result only in a speed up of the algorithm without qualitative improvements to the problem solutions. To gain better problem solutions, we use the theory of punctuated equilibria to design a parallel genetic algorithm [5] [9]. A genetic algorithm with punctuated equilibria is a parallel genetic algorithm in which independent subpopulations of individuals with their own fitness function evolve in isolation, except for an exchange of individuals (migration) when a state of equilibrium throughout all the subpopulations ....

N. Eldredge and S.J. Gould, "Punctuated Equilibria: An Alternative to Phyletic Gradualism", T.J.M. Schopf, ed., Models of Paleobiology, San Francisco, CA: Freeman, Cooper and Co.,

....a genetic algorithm [2] However, most of these methods result only in a speed up of the algorithm without qualitative improvements to the problem solutions. To gain better problem solutions, we designed a parallel genetic algorithm inspired by concepts from the theory of punctuated equilibria [7] [12]. A genetic algorithm with punctuated equilibria is a parallel genetic algorithm in which independent subpopulations of individuals with their own fitness functions evolve in isolation, except for an exchange of individuals (migration) when a state of equilibrium throughout all the subpopulations ....

.... gained in five independent runs (see right hand plot of Figure 7) Variable Epoch Lengths The ideas surrounding punctuated equilibria might be used to suggest: 1) a population in a constant environment will stabilize over time with little motivation for further development ( stasis [12]) and (2) bursts of rapid evolution are often caused by small sets of individuals migrating to a new environment ( allopatric speciation [12] We, however, are interested in evolutionary systems for optimization, so we have used these ideas to design a model in which the evolutionary system has ....

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N. Eldredge and S. J. Gould, "Punctuated Equilibria: An Alternative to Phyletic Gradualism," in Models of Paleobiology, T. J. M. Schopf, ed., San Francisco, CA: Freeman, Cooper and Co., 1972 pp. 82-115.

....between groups of individuals from di erent locations is controlled by some strategy and may depend on the distance or the relationship between the locations. Much work in spatial separation was inspired by the shifting balance theory (Wright, 1968) and the theory of punctuated equilibria (Eldredge Gould, 1972). One approach is to divide the population into a number of subpopulations. Each subpopulation evolves on its own island and individuals migrate between the islands at certain rate. In this way, the genetic material is exchanged within each of the subpopulations often while its ow to other ....

Eldredge, N., & Gould, S. (1972). Punctuated equilibria: an alternative to phyletic gradualism. San Francisco, CA: Freeman & Company.

....Kauffman and Walliser 1990) often followed by a burst of speciation. These observations are inconsistent with a purely gradualistic view, which would predict a more or less constant turnover of species. Punctuated equilibria Seeking to explain the evident stop start nature of the fossil record Eldredge and Gould (1972) proposed the theory of punctuated equilibria. According to this theory, species tend to remain stable for long periods of time. The equilibrium is punctuated by abrupt changes in which existing species are suddenly replaced. Many biologists have queried the theory, arguing that speciation could ....

Eldredge, N. and Gould, S.J. (1972). Punctuated equilibria: an alternative to phyletic gradualism. in T.M. Schopf (ed.) Models in Paleobiology. Freeman, Cooper, San Francisco.

....interactions among the components of the system changes the habilis. It can be asked why only the African Dryopithecines participated in the evolutionary line to Homo I believe that the origin of Australopithecines represented a unique evolutionary transformation such as it is postulated by Eldredge and Gould (1972) in their punctuated equilibria. It was likely therefore to be unique to a small isolated population. The reminder of the Dryopithecines went on to eventual extinction. Eccles, 1989 p. 12) 15 landscape from the K=O case where it is single peaked and smooth to the K = N 1 case where it ....

Eldredge N., Gould S. J (1972) Punctuated Equilibria: an Alternative to Phyletic Gradualism. In Schopf T. J. M. Ed.. Models in Paleobiology pp. 82-115 Freeman Cooper & Co, S. Francisco.

....models. However, it is in its approach to nonlinearity that Babbage s model departs most signi cantly from modern models. There is a super cial resemblance between the catastrophist debate of the 19th century and the more recent dispute over the theory of punctuated equilibria introduced by Eldridge and Gould (1973). Both arguments revolved around the signi cance of what appear to be abrupt changes at geological time scales. However, while Babbage s dispute centered on whether change could be explained by one continuously operating process or must involve two di erent mechanisms (the rst being geological ....

Eldridge, N., & Gould, S. J. (1973). Punctuated equilibria: An alternative to phyletic gradualism. In Schopf, T. J. M. (Ed.), Models in Paleobiology, pp. 82-115. Freeman, Cooper and Co, San Francisco.

....diversity, D B. In this way, the relations among D, W , and B clearly distinguish the quasi clonal and random agent populations. 3. 1 Punctuated Equilibria One of the most controversial topics in recent evolutionary biology has been the existence, cause, and implications of punctuated equilibria [13, 17, 10, 23, 26]. Artificial life systems might shed some new light on this controversy, since they often display punctuated equilibria in quantities like species concentration and average fitness (e.g, 19, 21, 28] Yet the causes of these punctuated dynamics remain uncertain. Ecological complications such as ....

N. Eldredge and S. J. Gould, 1972, "Punctuated Equilibria: An Alternative to Phyletic Gradualism," in T. J. M. Schopf, ed., Models in Paleobiology, Freeman, Cooper and Company, San Francisco.

....are correct, this must also be the case for natural evolution. In fact, hardly ever does one catch the latter doing other than routine maintenance and minor parameter tracking: the average duration of a species is a few million years, and during this time the phenotype hardly shows any changes (Eldredge and Gould 1972). As we saw in Section 3, if one were allowed to put into the tness function a sequence of incrementally graded intermediate goals ( If in state S 1 please evolve to S 2 ; if in S 2 , try to get to S 3 ; and so forth) or, equivalently, if one were allowed to use a variable tness function that ....

Eldredge, Niles, and Stephen Gould, \Punctuated equilibria: An alternative to phyletic gradualism", in T. Schopf (ed.), Models in Paleobiology, Freeman (1972), 82-115.

....of consistency are fundamentally reordered. Punctuated equilibrium has been proposed as an alternative perspective subsuming both traditional views on organizational change (Choi, 1995) The Punctuated Equilibrium View Punctuated equilibrium was first proposed in the field of paleontology by Eldridge and Gould (1972). In brief, the original punctuated equilibrium model proposed that species generally remain in stasis and that only infrequent transformations (i.e. punctuations) permit the generation of new species. More recently, Tushman and Romanelli (1985) Gersick (1991) and Romanelli and Tushman (1994) ....

Eldridge, N. and Gould, S. "Punctuated Equilibria: An Alternative to Phyletic Gradualism," In Models in Paleobiology, T. J. Schopf (Ed.), Greeman, Cooper &Co., San Francisco, CA, 1972, pp. 82-115.

....can decrease if both sexes benefit from the innovation) and a new species may emerge as it becomes reproductively isolated from other populations. The result could look like a period of rapid evolution concentrated around a speciation event, just as described by punctuated equilibrium theory (Eldredge Gould, 1972). Moreover, and more speculatively, it could be that if the new adaptive zone happens to be particularly large and fruitful, and the economic innovation proves particularly advantageous, then the event will appear as the establishment of a key evolutionary innovation, and may lead to the formation ....

Eldredge, N., & Gould, S. J. (1972). Punctuated equilibria: An alternative to phyletic gradualism. In T. J.

.... careful analysis of the fossil record; computer simulation may be more useful in determining whether this peak jumping mechanism is plausible (see Todd Miller, in preparation) This possibly rapid shift between fitness peaks resembles what Simpson (1944) called quantum evolution or what Eldredge and Gould (1972) called a punctuation . The quantum evolution term is apt because our theory suggests that populations capable of sexual dimorphism can do a kind of quantum tunneling between adaptive peaks: the normal economic costs that slow movement across low fitness valleys between peaks can be over ridden ....

....The lucky population will enter a new adaptive zone, rapidly climb the new peak, and may often become reproductively isolated from other populations. The result could look like a period of rapid evolution concentrated around a speciation event, just as described by punctuated equilibrium theory (Eldredge Gould, 1972). Moreover, if the new adaptive zone happens to be particularly large and fruitful, and the economic innovation proves particularly advantageous, then the event will look like the establishment of a key evolutionary innovation, and may lead to the formation of new higher taxa. 7 Speciation 7.1 ....

Eldredge, N., & Gould, S. J. (1972). Punctuated equilibria: An alternative to phyletic gradualism.

....size and migration rate are shown to have an effect. In real world genetics, the theories of shifting balance ( 16] in which small local populations can drift around the fitness landscape, exploring it more thoroughly than a single well mixed population) and punctuated equilibria ([4], where speciation develops in isolated groups, and the injection of new individuals produces a new period of rapid evolution) propose alternative explanations. 2.2.2 Implementation using MPI The limitation of exchange between demes renders the distributed GA ideally suited for coarse grain ....

N. Eldredge and S. J. Gould, `Punctuated Equilibria: An Alternative to Phyletic Gradualism ', In Models in Paleobiology, ed T. J. M. Schopf, 82--115, Freeman Cooper (1972).

....motion which allows us to find higher fitness sequences on landscapes with higher degrees of neutrality. Van Nimwegen et al. 10] have dubbed these periods of apparent stasis epochs . They also bear some similarity to the palaeontological punctuated equilibria described by Eldredge and Gould [23,24], although there are many other possible explanations for the periods of stasis seen in fossil evolution. To investigate the epochs in more detail, we have performed simulations of true populations evolving on our landscape. In these simulations we take a population of M sequences which at each ....

Eldredge, N. and Gould, S. J. 1972 Punctuated equilibria: an alternative to phyletic gradualism. In Models in Paleobiology, T. J. M. Schopf (Ed.), Freeman, San Francisco.

....subpopulations where each process followed the same procedure. Cohoon, Hedge, Martin and Richards investigated the effects on the evolution process of having a diversity of environmental characteristics across the populations [7] Here they are influenced by the theory of punctuated equilibria [14]. In short this theory holds that the emergence of new species can be associated with very rapid evolutionary development after a geographically separation. Thus they proposed a distributed genetic algorithm where each subpopulation evolves until it reaches equilibrium in a stable environment ....

N. Eldredge and S.J. Gould; `Punctuated Equilibria: an Alternative to Phyletic Grdualism'; In: Models of Paleobiology. 82-115, Freedom, T.J. Schopf, 1972.

....they shall be presented as a class of parallel GAs called coarse grained parallel GAs, in Subsection 2. 2, spatial separation, a basic principle of DGAs, is justified from a biological point of view through the Shifting Balance Theory of Evolution ( 58] and the Theory of Punctuated Equilibria ([15]) in Subsection 2.3, we describe the basic structure of DGAs, and finally in Subsection 2.4, we review the types of DGAs presented previously. 2.1 Parallel Genetic Algorithms The availability, over the last few years, of fast and cheap parallel hardware has favored research into possible ways ....

....Even if drift were to drive every local deme to fixation, each one of them would be fixed on a different genotype, thereby maintaining diversity in the population as a whole. Another biological theory adopted by people who do work on spatial separation is the theory of Punctuated Equilibria ([15]) This theory states that evolution is characterized by long periods of relative stasis, punctuated by periods of rapid change associated with specialization events. In [8] it is pointed out that GAs also tends towards stasis, or premature convergence and that isolated species could be formed by ....

N. Eldredge, S.J. Gould, Punctuated Equilibria: An Alternative to Phyletic Gradualism. In: Models of Paleobiology, T.J.M Schopf (Ed.) (San Francisco, CA: Freeman, Cooper, 1972), 82-115.

....A.1, they shall be presented as a class of parallel GAs called coarse grained parallel GAs, in Section A. 2, spatial separation, a basic principle of DGAs, is justified from a biological point of view through the Shifting Balance Theory of Evolution ( 71] and the Theory of Punctuated Equilibria ([17]) in Section A.3, we describe the basic structure of DGAs, in Section A.4, we review the types of DGAs presented previously and finally, in Section A.5, we tackle heterogeneous DGAs, reporting on the different approaches presented, and explaining the position of the GD RCGAs relative to these ....

....Even if drift were to drive every local deme to fixation, each one of them would be fixed on a different genotype, thereby maintaining diversity in the population as a whole. Another biological theory adopted by people who do work on spatial separation is the theory of Punctuated Equilibria ([17]) This theory states that evolution is characterized by long periods of relative stasis, punctuated by periods of rapid change associated with speciation events. In [10] it is pointed out that GAs also tends towards stasis, or premature convergence and that isolated species could be formed by ....

N. Eldredge, S.J. Gould, Punctuated Equilibria: An Alternative to Phyletic Gradualism. Models of Paleobiology, T.J.M Schopf (Ed.), (San Francisco, CA: Freeman, Cooper, 1972), 82-115.

....Figure 5: Short time evolutionary behavior. Parameters: soup size M = 10 5 , automata reaction with table 2, filter condition f 1 , soup seeded with M random strings. The phenomenon that long quasi stable periods are interrupted by rapid changes is often referred to as punctuated equilibrium [11]. It has been observed in natural as well as in artificial systems (e.g. DNA world [28] and multi agent systems [33] For a more detailed analysis of the organization structure the reaction table can be used. Figure 8 and 9 show a part of the reaction table of the 90 most frequent strings at ....

N. Eldridge and S. J. Gould. Punctuated equilibria: An alternative to phyletic gradualism. In T. M. Schopf, editor, Models in Paleobiology, pages 82--115. Freeman, Cooper a. Co, San Francisco, 1972.

No context found.

Eldredge, N. and Gould, S. (1972). Punctuated Equilibria: An Alternative to Phyletic Gradualism, chapter 5, pages 82--115. Freeman, Cooper and Co.

No context found.

Eldredge, N., & Gould, S.J. (1972). Punctuated equilibria: An alternative to phyletic gradualism. In T.L.M. Schopf (Ed.), Models in paleobiology (pp. 82115) . San Francisco: Freeman.

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Eldridge, N. & Gould, S. (1972), Punctuated Equilibria: An Alternative to Phyletic Gradualism, Models of Paleobiology, pp 82-115.

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N. Eldredge and S.J. Gould, Punctuated equilibria: an alternative to phyletic gradualism in Models in Paleobiology, Freeman, Cooper and Co., San Francisco (1972).

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ELDREDGE, N. and GOULD, S.J. (1972), "Punctuated Equilibria: An Alternative to Phyletic Gradualism", in: Models in Paleobiology, ed. T.J.M. Schopf, San Francisco, 82-115.

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