Is there a problem with Punctuated equilibrium?
Summary of problems with claim:
Explore Evolution claims punctuated equilibrium is a more accurate description of the fossil record, but species selection doesn't work as a mechanism so punctuated equilibrium can't explain the origin of new body plans or new structures. So punctuated equilibrium confirms that there are few transitional forms, but leaves no mechanism for explaining transitions.
On this page, Explore Evolution finally tackled punctuated equilibrium, a major evolutionary idea first proposed by Niles Eldredge and Stephen Jay Gould in 1972.
Explore Evolution says:
In the traditional view, the fossil record was always to blame for the missing pieces of the evolutionary puzzle Eldredge and Gould decided to take a different approach. Instead of blaming the fossil record, they accepted the fossil data at face value. They agreed that the fossil record really does show many groups of organisms appearing abruptly, continuing unchanged for millions of years, then going extinct.Explore Evolution, p. 32
Explore Evolution's tone in this quote is one of gloating: Here Darwin has been corrected by real scientists. If Darwin was wrong on one point, Explore Evolution suggests, Darwin might have been wrong on every point. This is, of course, false logic. Moreover, Explore Evolution fails to understand that science is replete with corrections and clarifications of existing theories; ongoing research and critical testing, far from being a sign of the weakness of the theory of evolution, is a sign of its strength.
This is one of the ways in which science is fundamentally different from other human endeavors. In science, no idea is unquestionable, no expert beyond criticism, no theory safe from new evidence. There are no authorities, no equivalent of a clergy to whom one can turn for infallible answers.
In a sidebar, Explore Evolution says:
The Vendian Fossils: Was the 'Cambrian Explosion' Really Explosive? Some scientists have suggested that those odd creatures may well be the fossilized intermediates that neo-Darwinists have been looking for.Explore Evolution, p. 32
The exact relationship of the Ediacarans to modern animals is very unclear. Some of the Ediacarans do not even appear to be animals, as they lack features such as mouths and anuses and digestive tracts. But if there is any phylogenetic relationship between the Ediacarans and modern phyla, then this means they probably weren't "intermediate," but rather first.
Explore Evolution says:
Many critics of the theory pointed out that punctuated equilibrium has never explained how the major changes recorded in the fossil record could have taken place in such a short time.Explore Evolution, p. 33
Eldredge & Gould's punctuated equilibrium concept is based on observations of the fossil record. The "how" or "why" of changes is not required to understand the "what" of the observations.
In fact, arguing that a concept must be wrong if it does not contain a ready explanation of how it occurs is an exercise in teleology. Teleology is concerned with design of things and their inherent purpose. This presupposes, however, that there is a design, that there is a purpose, and such an assumption is not part of science.
As an analogy, imagine that a teleologist argued against a quantum physicist about the structure of the proton. Sure, the teleologist might say, you can prove with your fancy machines that a proton is composed of two up-spinning quarks and one down-spinning quark, but if you cannot say why, then this invalids your observation. Such an argument would, of course, be absurd--yet this is precisely the argument Explore Evolution makes about punctuated equilibrium.
[Punctuated equilibrium] does not explain the origin of higher taxonomic groups (like phyla or classes). To describe how one species of trilobite evolved into another is not the same as explaining how trilobites arose in the first place.Explore Evolution, p. 33
Eldredge and Gould never claimed that punctuated equilibrium explained the origin of the phyla. It does, however, do a darn good job of explaining the changes in trilobites.
If the theory of Punctuated Equilibrium is right about the rate of evolutionary change then it has no mechanism that can produce new structures as rapidly as the fossil record shows.Explore Evolution, p. 33
Eldredge and Gould never claimed that punctuated equilibrium could explain the rate of new body structures. Punctuated equilibrium focuses on what we can see in the fossil record, leaving broader explanations for subsequent research.
Recent discoveries involving the Hox and Pax genes have, in fact, shown how major body plan changes can be made from relatively minor genetic variation. The Pax-6 gene, for example, is common to both invertebrates and vertebrates, and small changes determine whether and organism develops a compound eye (like a fly) or a eye with a cornea and lens (like a human eye) (Zuker, 1994).
It is hard to refute unnamed, anonymous "critics." This is like being accused of a crime, but being unable to question witness against you. If Explore Evolution were serious about this, each one of these three statements would have several examples from the peer-reviewed literature to back up each claim. A search of the peer-reviewed literature turns up, however, zero peer-reviewed papers showing "critics of both views" agreeing that there are fewer than "expected" transitional fossils.