Punctuated equilibrium

[The Seeker]

I've heard a lot about both punk eek, but only in passing, I understand gradualism quite well, as it's taught at high school level, but I don't really know from punk eek. Can sombody furnish me with a bit of info please?

N.b. I'm not interested in creationist rants about how punk eek says that dogs give birth to cats.

 

[NamesAreHardToPick]

The Structure of Evolutionary Theory by Steven Jay Gould. Great source for it.

 

[mark kennedy]

In neodarwinian thought gradualism is an unbroken line of successive slight modification accumulated over time. Goldshmidt was a brilliant scientist who was thought to be misguided when he suggested that it was plausable that a macroevolutionary change could happen in one generation. Gould thinks this idea not only has merit but that it allways has been, in fact he predicts that puncuated equilibrium will be completly vindicated in our day. Here is his discussion on the subject and punctuated equilibrium is considered a modern perspective on evolutionary thought.

"Many evolutionists view strict continuity between micro- and macroevolution as an essential ingredient of Darwinism and a necessary corollary of natural selection. Yet, as I argue in ["The Episodic Nature of Evolutionary Change"], Thomas Henry Huxley divided the two issues of natural selection and gradualism and warned Darwin that his strict and unwarranted adherence to gradualism might undermine his entire system. The fossil record with its abrupt transitions offers no support for gradual change, and the principle of natural selection does not require it—selection can operate rapidly. Yet the unnecessary link that Darwin forged became a central tenet of the synthetic theory.
Goldschmidt raised no objection to the standard accounts of microevolution; he devoted the first half of his major work, The Material Basis of Evolution (Yale University Press, 1940), to gradual and continuous change within species. He broke sharply with the synthetic theory, however in arguing that new species arise abruptly by discontinuous variation, or macromutation. He admitted that the vast majority of macromutations could only be viewed as disastrou—these he called "monsters."

http://www.evolutionary.tripod.com/gould_nh_86_22-30.html

In case someone wanders in here interested in a Creationist perspective Bert Thompson has written an essay on the subject.

http://www.markehrlich.com/authors/BThmepee.html

 

[aggo]

Essentially, Punctuated Equilibrium are long periods of "microevolution" or perhaps, no evolution, followed by a rapid changes in populations [of organisms] which may arrive from natural disasters.

 

[Hydra009]

http://en.wikipedia.org/wiki/Punctuated_equilibrium

 

[Oncedeceived]

I've heard a lot about both punk eek, but only in passing, I understand gradualism quite well, as it's taught at high school level, but I don't really know from punk eek. Can sombody furnish me with a bit of info please?

N.b. I'm not interested in creationist rants about how punk eek says that dogs give birth to cats.

What is this..evolution 101 day?

 

[Arikay]

Punk Eek also suggests that a split off group will find a seperate area or niche to evolve in then eventually take over the entire area. This causes the appearance of a jump in the fossil record. The jump can be smoothed out if you can find the small area that they split off to. I believe this has been supported by finds that show it happening.

 

[kingreaper]

In neodarwinian thought gradualism is an unbroken line of successive slight modification accumulated over time. Goldshmidt was a brilliant scientist who was thought to be misguided when he suggested that it was plausable that a macroevolutionary change could happen in one generation. Gould thinks this idea not only has merit but that it allways has been, in fact he predicts that puncuated equilibrium will be completly vindicated in our day.

This is incorrect, punctuated equilibrium doesn't work on a single generation level, it isn't (as it is often charecterised) saltationism




The rest is thereofre irrelevant



Punctuated equilibrium is basically the concept that evolutionary change will sometimes occur slowly and sometimes faster



Mechanisms for this generally involve geographic isolation encouraging faster evolution, IMO this is because geographically isolated populations can be more easily sent into high frequency lopw bottomed population density wave (where there population reaches its uppermost and lowermost limits within only a few generations, and has a low bottom limit) resuloting in repeated bottlenecks and repeated radiations, which I'd expect to be a recipe for faster evolution

 

[Anjinsan]

Simplest way I can think of:

Periods of greater selective pressure will result in periods of greater evolutionary rate of change.

 

[gluadys]

In neodarwinian thought gradualism is an unbroken line of successive slight modification accumulated over time. Goldshmidt was a brilliant scientist who was thought to be misguided when he suggested that it was plausable that a macroevolutionary change could happen in one generation. Gould thinks this idea not only has merit but that it allways has been, in fact he predicts that puncuated equilibrium will be completly vindicated in our day. Here is his discussion on the subject and punctuated equilibrium is considered a modern perspective on evolutionary thought.

No, Mark. You are confusing punctuated equilibrium with saltationism. Read the Wikipedia article to see the difference. Gould never abandoned the idea that evolution could only proceed in small steps. He just said the small steps needn't be slow ones.