Plying the mind of Biplane

Bill,

Can you give me a laymans summation of punctuated equalibrium?

Thanks,

~ Fartin

I abstain. I understand most of what he says. Except when he does the badger dance.

I didn't vote because I do understand what he says... and I don't know what the badger dance is, though that's probably best.

Of course I understand Bill's every word but that doesn't mean I have to listen to his every word (Moms can do that) By the way the first reponse has a spelling error.

Puctuated equilibrium (in contrast to gradualism) is one view within the field of natural history. In essence, under a punctuated equilibrium continuum, life undergoes very little change for a very long time, and then there is an explosion of rapid change and niche radiation (such as the so-called "Cambrian explosion," wherein a great number of the known modern phyla began to appear over a few short million years). This is opposed by gradualism, where, as the name suggests, gradual but constant change occurs over a time period (such as what may have occurred during the Devonian Period).

Biplane's brain out.

*Grin*

Biplane out.

Translation: short bursts of rapid evolution. (I took classes in speaking Bill)

Ya got me Jamaican! I stand translated.

Biplane out.

Puctuated equilibrium (in contrast to gradualism) is one view within the field of natural history. In essence, under a punctuated equilibrium continuum, life undergoes very little change for a very long time, and then there is an explosion of rapid change and niche radiation (such as the so-called "Cambrian explosion," wherein a great number of the known modern phyla began to appear over a few short million years). This is opposed by gradualism, where, as the name suggests, gradual but constant change occurs over a time period (such as what may have occurred during the Devonian Period).

Biplane's brain out.

That's pretty much what I remembered on it. Who's theory was this? Gould? Also, is there agreement in the scientific community about which one is most likely to have occured based on the fossil record? Or is a little bit of this and a little bit of that the story?

~ M

Yep. Gould and Eldridge, back in the 70's. The gradualism/Punctuated Equilibrium question is under significant debate, and always has been since the theory was proposed, and likely always will be. Many parts of the fossil record point to very rapid (in a geologic sense) evolution in several periods of geologic time. In particular the Cambrian Period I alluded to previously, in which most of the phyla of Kingdom Animalia first began to appear in the fossil record in just (let me check this now) a 53 million year period. Seems like a long time, no? I mean when you consider that the pyramids are at most perhaps 5,000 years old...and that the first man (or woman) to build a house and plant a seed did so about 12,000 years ago? I mean, a million years is a long time, right?

Well...no.

Not geologically. If it helps to give some perspective, think of the history of time as a single hour. Animal life did not appear until the last ten minutes of this hour, and the whole of human history, everything we've ever known or done, encompasses all of 1/100th of a second of this hour.

For the vast amount of species that began to evolve during this period, 53 million years was extremely rapid. That's about...1/2 a minute on our clock of time.

So...the Cambrian explosion supports Gould's theory very much. Also Gould almost certainly was correct in his description of isolated populations undergoing speciation (which is to say, parts of brook trout populations, for example, that are separated from the rest of the brook trout began to slowly become...not brook trout). There are already a number of sub-species out there which are different from their conspecifics in certain ways, usually color or behavior. For example, the black morph of the gyrfalcon is very common in the Northwest Territories and Nunavut, in northern Canada. Subspecies of black bear (appalachian, western, pacific northwest), gray wolf (timber, arctic), amphibians (particularly salamanders around here), and of course Homo sapiens sapiens (Scandanavian, Asian, Germanic, Middle Eastern, Amerindian, African, etc.).

Really, I think he was spot on with speciation, and in some instances (like the Cambrian Explosion and the post-Mesozoic and post-Great-Dying time periods) there seems to be evidence for rapid evolution in a short period, but I personally say that Gould's theory isn't the whole story. I believe that there have been cases where gradual change has been the driving force in the emergence of new species.

Whew.

Biplane out.

Yeah... sorry about that. Little long. Got a little too excited about it.

Biplane out.

No prob, sounds like the good explanation I was expecting actually. Thanks.

~ M

So when can we expect your first professional publication?

Heh...professional publication...that'll be the day.

( the blue guy is bill)