Natural Selection Shrinks Herd of Kansas Darwinists

Gould and Eldridge's punctuated equilibrium has become a contestable theory, and it does seem to have gone thru the typical progression of being laughed away, rejected, and then finally supported such that people say its allways been true.

In effect, their idea takes Ernst Mayr's ideas on 'allopatric speciation' (mayr is also the one who came up with the biological species concept that I use above) and try to apply it to the fossil record. Mayr felt that you'd get a new species when a population of one species was phyiscally seperated, either by moving onto an island on into a different region, and then differences would accumulate, sometimes at an accelerated rate since there was a smaller population (and thus not as many 'normals' to 'wash out' the new unusual variation). Whats called "founder's effect' also comes into play there.
So Gould and Eldridge figured, what would this mean in the fossil record, and the result is punctuated equilibria. So lots of people have said that they're really not saying anything new. Also, like I try to explain above, every species is transitional, and all 'transitionals' are just regular species, not a thing that is struggling to finish 'evolving' into a stable and adaptive sort of species.

Gould and Eldridge's ideas are still pretty widely debated tho and from what I understand most evolutionists don't readily accept them, or even consider them to be particularly meaningful. Punctuated Equilibria is however recognized tobe a genuine phenomenon, and there are a few cases from the fossil record that fit it and confirm its existence.

So punctuated equilibria is still 'gradual', its just that 'gradual' in terms of the evolution of species can be too fast and on too small a scale to be preserved in the fossil record; punctuated equilibria doesn't involve any 'new' genetics or speciation mechanisms or anything like that. It's a 'new' idea because paleontologists were apparently behind population biologists in terms of their thinking about speciation. Paleontologists tended, appparenty, to think of speciation as being ploddingly slow, and expected that a full fossil record will allways show very slow, very gradual accumulation of changes within all members of a lineage (anagenesis or complete transformation), whereas geneticsts can population biolgists were theorizing that it occurs via the splitting of lineages.

But basically we don't have all the transitionals that we'd like because of the spottiness of the fossil record, which, interestingly, was Darwin's own explanation (however paleontology was woefully underdeveloped in his time and I doubt he'd be concerned about a lack of 'transitionals' if he saw the current record).