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Punctuated equilibrium

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Punctuated Equilibrium is a theory popularized by the late Stephen Jay Gould to explain the absence of transitional forms in the fossil record, which are predicted by Darwinian evolution, as well as "stasis" - the fact that species in the fossil record remain largely unchanged for long periods in the fossil record rather than showing transitions. It is a modern version of the saltation theory that was largely held by the evolutionists of Darwin's day. The punctuated equilibrium theory was first presented in Punctuated Equilibria: An Alternative to Phyletic Gradualism,[1] in an attempt to explain away the complete lack of evidence for macroevolution in the fossil record.

"Closely related (perhaps descendant) species that enter the rock column should appear suddenly and show no intergradation with the "ancestral" species in morphological features that act as inter-specific differentia. There should be no gradual divergence between the two species when both persist for some time to higher stratigraphic levels." (pp. 95-96)

Most organisms in the fossil record appear suddenly, then remain unchanged for long periods of time. The theory attempts to explain this observation by asserting that species can change instantaneously on geologic time scales (i.e thousands of years).[2] Rapid species evolution is believed to occur as a result of episodic changes in the environment, such as floods or droughts, which are then followed by long periods of stasis. Because of these sudden environmental changes, species must adapt rapidly (punctuated), but then remain unchanged afterwards for long periods of time (equilibrium).

In essence, the theory used the complete lack of evidence for macroevolution, and the evidence from the geologic record that gradualistic evolution does not occur, but rather sudden appearance of complexity indicative of instantanteous creation with minimal microevolution within parent species, to support a new theory supportive of evolutionary theory. Rather than following the logical conclusion that sudden appearance of complexity and microevolution indicates a Creator, Gould and Eldredge used the lack of evidence for macroevolution in the fossil record to propose that evolution just goes too rapidly in short bursts to be witnessed in the geologic record.

History

The theory was first proposed by paleontologists Niles Eldredge and Stephen Jay Gould in 1972 within a paper titled; Punctuated Equilibria: An Alternative to Phyletic Gradualism[3] who hoped it would expand on the theory of evolution far more than Charles Darwin could have ever imagined. The underlying current of the paper that interpretations gleaned when guided by theoretical determinations, rather then following the guidelines within the scientific method, is something which both authors found it quite necessary to display. It is the grasp of phyletic gradualism upon the search for true evidential observation within science that Eldredge and Gould attempt to alleviate through their alternative interpretation of the fossil record.

"Still, if evolution is gradual, there should be a fossilized record of small, incremental changes on the way to a new species. But in many cases, scientists have been unable to find most of these intermediate forms. Darwin himself was shaken by their absence. His conclusion was that the fossil record lacked these transitional stages, because it was so incomplete. That is certainly true in many cases, because the chances of each of those critical changing forms having been preserved as fossils are small. But in 1972, evolutionary scientists Stephen Jay Gould and Niles Eldredge proposed another explanation, which they called 'punctuated equilibrium.' That is, species are generally stable, changing little for millions of years. This leisurely pace is 'punctuated' by a rapid burst of change that results in a new species and that leaves few fossils behind."

-Prentice-Hall on PBS[4]

Gould likened his attempts as reinforcement of a three-legged stool that is evolution. Leg one being genealogical hierarchy, leg two constraints of systems such as natural selection and leg three being the environment of which Gould thought he gave a greater role then Darwin himself did.[5]

Unevidenced

The paper begins by arguing against Newtonian inductivism (pg. 84) and claims the proper approach is theory without "patient accumulation of facts", asserting the "cloven hoofprint of theory" is inevitable:

"Today, most philosophers and psychologists would brand the inductivist credo as naive and untenable on two counts:
(1) We do not encounter facts as 'data' (literally 'given') discovered objectively. All observation is colored by theory and expectation. (See Vernon, 1966, on the relation between expectation and perception. For a radical view, read Feyerabend's (1970) claim that theories act as 'party lines' to force observation in preset channels, unrecognized by adherents who think they observe an objective truth.
(2) Theory does not develop as a simple and logical extension of observation; it does not arise merely from the patient accumulation of facts. Rather, we observe in order to test hypotheses and examine their consequences. Thus, Hanson (1970, pp.20-23) writes: 'Much recent philosophy of science has been dedicated to disclosing that a 'given' or a 'pure' observation language is a myth-eaten fabric of philosophical fiction... In any observation statement the cloven hoofprint of theory can be readily detected.'" (pg. 85)

Gould and Eldredge then admit Darwinian gradualism has been incorrect, and that "an inadequate picture has been guiding our thoughts on speciation for 100 years... because paleontologists, in claiming that they see objectively, have not recognized its guiding sway". A particularly telling quote, revealing they just invented the theory to protect Darwinism rather than through factual examination, is "To extract ourselves from this dilemma, we must bring in a more adequate theory: it will not arise from facts collected in the old way":

"The inductivist view forces us into a vicious circle. A theory often compels us to see the world in its light and support. Yet, we think we see objectively and therefore interpret each new datum as an independent confirmation of our theory. Although our theory may be wrong, we cannot confute it. To extract ourselves from this dilemma, we must bring in a more adequate theory: it will not arise from facts collected in the old way...
This issue is central to the study of speciation in paleontology. We believe that an inadequate picture has been guiding our thoughts on speciation for 100 years. We hold that its influence has been all the more tenacious because paleontologists, in claiming that they see objectively, have not recognized its guiding sway. We contend that a notion developed elsewhere, the theory of allopatric speciation, supplies a more satisfactory picture for the ordering of paleontological data." (pg. 86)

Quotes from Punctuated Equilibria

The following are quotes from the Gould and Eldredge paper:

"Charles Darwin viewed the fossil record more as an embarrassment than as an aid to his theory. Why, he asked (1859, p. 310), do we not find the ‘infinitely numeral transitional links’ that would illustrate the slow and steady operation of natural selection? ‘Why then is not every geological formation and every stratum full of such intermediate links? Geology assuredly does not reveal any such finely graduated organic chain; and this, perhaps is the gravest objection which can be urged against my theory’ (1859, p. 280). Darwin resolved this dilemma by invoking the great inadequacy of surviving evidence (1859, p. 342): ‘The geological record is extremely imperfect and this fact will to a large extent explain why we do not find interminable varieties, connecting together all the extinct and existing forms of life by the finest graduated steps. He who rejects these views on the nature of the geological record, will rightly reject my whole theory.' Thus Darwin set the path for the new science of evolutionary paleontology: to demonstrate evolution, search the fossil record and extract the rare exemplars of Darwinian process—insensibly graded fossil series, spared somehow from the ravages of decomposition, non-deposition, metamorphism, and tectonism." (pg. 87)
"To Darwin, therefore, speciation entailed the same expectation as phyletic evolution: a long and insensibly graded chain of intermediate forms. Our present texts have not abandoned this view, although modern biology has." (pg. 89)
"Under the influence of phyletic gradualism, the rarity of transitional series remains as our persistent bugbear. From the reputable claims of a Cuvier or Agassiz to the jibes of modern cranks and fundamentalists, it has stood as the bulwark of anti-evolution arguments: 'For evolution to be true there had to be thousands, millions of transitional forms making an unbroken chain' (Anon., 1967-From a Jehovah's Witnesses pamphlet)." (pg. 90)
"After it is fully established, a descendant species is as unlikely to show gradual, progressive change as is the parental species. Thus, in the fossil record, we should not expect to find gradual divergence between two species in an ancestral-descendant relationship. Most evolutionary changes in morphology occur in a short period of time relative to the total duration of species. After the descendant is established as a full species, there will be little evolutionary change except when the two species become sympatric for the first time." (pg. 95)
"Closely related (perhaps descendant) species that enter the rock column should appear suddenly and show no intergradation with the "ancestral" species in morphological features that act as inter-specific differentia. There should be no gradual divergence between the two species when both persist for some time to higher stratigraphic levels." (pp. 95-96)

Darwinian Gradualism

Main Article: Gradualism

Sudden and overwhelming change then maintained special stasis for long periods of time can be supported by observation of organisms as fossils in the geological column. On the other hand Gradualism, a major tenet of Darwin, posits change in small step-wise fashion of which many intermediate fossils should be visible if true. The morphological discontinuity and the geologic time scales involved (i.e decades or hundreds of years instead of thousands or millions) puts Punctuated Equilibrium in direct contrast with Gradualism; essentially an acknowledgement that species appeared suddenly in advanced stages without the gradual transitions required for a common ancestor. The lack of transitional forms in the fossil record troubled Darwin himself, who tried to explain it through the then-incomplete knowledge of the fossil record.[6]

Within an evolutionary framework Punctuated Equilibrium demands radical, sudden change in the time required for a cohesive relationship to form, attributed to the natural selection of beneficial mutations in populations of organisms. With the necessity of extrapolation and reliance on deep time to claim molecules-to-man evolution, punctuated equilibrium leaves little room to insist it is the source of such evolution.

Similarly, supporters of ‘jerky’ evolution (saltationism and its relative, punctuated equilibria) point out that the fossil record does not show gradualism, and that the hypothetical transitional forms would be disadvantageous. But supporters of gradual evolution point out that sudden, large, information-increasing change is so improbable that one would need to invoke a secular ‘miracle.’ Creationists agree with both sides: punctuated evolution can’t happen, and gradual evolution can’t happen—in fact, particles-to-people evolution can’t happen at all![7]

Falsifiability

The Biotic Message: Evolution Versus Message Theory by Walter ReMine accuses Punctuated Equilibrium of being unfalsifiable, of simply creating an unsubstantiated hypothesis to explain away the growing body of evidence seen from the fossil record that evolution is not constant and gradual, and that transitional forms don't exist.

"So is punctuated equilibrium testable? Gould says that a series of fossils showing gradual development of an adaptation would refute punctuated equilibrium. ReMine points out the 'no lose' situation that Gould and company have created here: if the fossils show systematic gaps, then the punctuated equilibrium model of evolution is 'proven', but if the fossils show gradualism, then the standard neo-Darwinian model of evolution is proven. In other words, evolution itself is no longer falsifiable! Punctuated equilibrium and neoDarwinism are both now part of the evolutionists' grab-bag of conflicting theories as Gould and Eldredge now view punctuated equilibrium as an addition to evolutionary theory rather than an alternative."

-Don Batten, review of "The Biotic Message" in Creation[8]

Theoretical Mechanisms

Main Article: Speciation

Speciation is the natural process by which new species are formed. A species is generally defined as a naturally-occurring breeding group that is reproductively isolated from other such groups. The formation of a new species most often occurs when members of a population become separated, preventing mating or genetic flow between the groups. Organisms that were once capable of interbreeding will gradually develop barriers to reproduction when segregated and exposed to differential selective pressures. This process results in two or more genetically distinct groups of organisms that are no longer capable of interbreeding (species).[9]

References

  1. "Competing Hypotheses About the Pace of Evolution." Understanding Evolution. University of California Museum of Paleontology. 29 April 2012.
  2. "Competing Hypotheses About the Pace of Evolution." Understanding Evolution. University of California Museum of Paleontology. 29 April 2012.
  3. Punctuated Equilibria: An Alternative to Phyletic Gradualism. Eldredge, N. and Stephen J. Gould. 1972.
  4. Prentice-Hall Inc. "Punctuated Equilibrium."
  5. Structure of Evolutionary Theory by Stephen Jay Gould
  6. Prentice-Hall Inc. "Punctuated Equilibrium."
  7. Sarfati, Jonathan. Refuting Evolution 2. Greenforest AR: Master Books, 2002. (p66)
  8. Batten, Don (1997). "The Biotic Message: Evolution versus Message Theory." CenTech J. Vol. 3, No. 11, pp. 295-296.
  9. Species By Biology-Online.org

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