Question: "What is the theory of punctuated equilibrium?"
Answer: “Punctuated equilibrium” refers to a concept in evolutionary biology that is both controversial and widely misunderstood. Both punctuated equilibrium and its alternatives have significant drawbacks, either in plausibility or evidence. Punctuated equilibrium seeks to reconcile the idea of natural evolution with the missing links in the fossil record. The debate within science over the validity of punctuated equilibrium demonstrates many of the problems with evolutionary theory in general.
Punctuated equilibrium attempts to answer a major problem with the fossil record. For almost a century, naturalistic science assumed that the gaps in the fossil record would eventually be filled, and there would be a semi-complete record of so-called “transitional forms” between the various species. In fact, the opposite happened, and the gaps became even more pronounced. The actual fossil record indicates species seemingly appearing from nowhere, and without the long, slow, gradual changes expected by classical evolutionary theory. Punctuated equilibrium seeks to answer this problem by supposing that evolution doesn’t occur steadily, but sporadically.
In 1972, Stephen Gould and Niles Eldredge published a landmark paper on punctuated equilibrium. Their contention was that the gaps in the fossil record were best explained by gaps in evolution. That is, that most species did not change much over time, but occasionally experienced major changes in brief periods of time. “Classic” Darwinian evolution is presumed to take place very gradually, with a steady and slow change of organisms over time. Punctuated equilibrium replaces this slow change with long periods lacking any change at all, mixed with relatively short periods of rapid change.
Another way of looking at this is to say that, according to punctuated equilibrium, species are normally not evolving, and when they do evolve, it is relatively quick and dramatic. At times, this has become a source of controversy within the scientific community. Depending on whom you ask, punctuated equilibrium is either a refutation of gradual evolution, or just a specific form of it. This is one of the major disagreements over the theory – whether it replaces or enhances the classical notion of naturalistic evolution.
Despite a better agreement with available evidence, there are many scientific problems with punctuated equilibrium itself. The mechanism for punctuated equilibrium is assumed to be small groups of a particular organism separated in some way from the main population. This would accelerate the transmission of mutated genes through the population, and much more quickly produce a new species. However, multiple studies have found that inbreeding such as this produces extremely negative effects, which run counter to the idea of rapid advancement. The fossil record also calls into question the plausibility of this notion. The so-called “Cambrian Explosion,” for instance, is the sudden emergence of almost every biological type known to man, in a geological blink of an eye. This seems to contradict the idea of broad genetic stability intermixed with localized change.
There are also several points of irony related to punctuated equilibrium that have little to do with the science, and a great deal to do with the assumptions of the scientists. Gould was criticized for being heavy on rhetoric and light on scientific substance by the “old guard” of evolutionary theory. This same criticism has been applied by theists to atheistic naturalism in general. Gould and Eldredge predicted resistance to their ideas, stating that the scientific community was too devoted to theories and not facts. That is, they expected to be resisted for no other reason than what they proposed didn’t follow the preferred assumptions. More than 30 years later, this is still one of the major obstacles to open, honest dialogue about science.
Punctuated equilibrium represents an odd combination of traits. It closes some holes in evolutionary theory, but opens up others. It supposedly makes evolutionary theory more evidence-based, and therefore more scientific, but it also makes the “naturalism of the gaps” attitude easier to take. That is, punctuated equilibrium makes it easier to explain away the lack of transitional forms as though it was evidence that actually supports evolution.
When all is said and done, punctuated equilibrium is an attempt to reconcile available evidence with the idea of naturalistic evolution. It is, in many ways, another example of re-interpreting facts in order to fit an ideology. Still, any willingness to modify evolutionary theory in light of evidence is good, since this can only lead closer and closer to the idea of a Creator God. Pursuit of these ideas might help close the philosophical gaps between atheistic naturalism and intelligent design – which might be the very reason punctuated equilibrium is so highly resisted in some academic circles.