So: gradualism or punctuated equilibrium?

[JohnLocke]

Punctuated equilibrium for me :hi:

[EstimatedProphet]

1. I'll have the punctuated equilibrium too.

[mike6640]

2. PE

with a few cataclymic events thrown in to get 'em rolling...

[Justin54B20L]

3. Yep, punctuated equilibrium here too, complemented by

both Founder's and Bottleneck effects.

[Psephos]

4. My guess is they're both right, and both wrong

Not trying to be a smart-ass, either. Maybe I should say neither has been developed fully enough yet.

The problem is that the fossil records are disjoint, incomplete, and jumbled. It's amazing how much we've been able to figure out from such a dog's breakfast of bones and stones. Just as importantly, elucidating the way phenotype and genotype interact, especially at the population level, has been very complex. (Genotype = blueprints; phenotype = actual body that gets built after blueprints interact with environment.)

Peace.

[glitch]

6. Both right.

Depends on what's required when needed, and what succeeds.

[hunter]

15. The genotype=blueprints anology can be misleading.

Comparing genes to computer software can also be misleading.

A lot of the misconceptions expressed by creationists and "intelligent design" theorists can be traced back to these "blueprint" or "software" analogies. While using these analogies it is very natural to ask who the ultimate "designer" of life might be. But this question is utterly irrelevant to the actual biology.

Steven Jay Gould, an originator and proponent of "puncuated equillibrium," faced very similar problems when the creationists and ID theorists seized upon his elegant analogy for their own purposes. "Puncuated Equillibrium" does not in any way validate creationism or "intelligent design," but many dishonest and ignorant people have claimed it does, which detracts greatly from the usefulness of the analogy.

I rarely use the analogy of "genotype=blueprints" or use the term "puncuated equillibrium" in my own writing because these words have been corrupted in a very Orwellian fashion by the creationsts.

[Psephos]

18. Very good points

As Einstein said, we should simplify things as much as possible, but not more than possible.

The blueprints analogy starts to fall apart quickly when we consider that gene expression is a dynamic, not static, process and cannot be understood well in isolation from the living organism.

Good point also about the misappropriation of Gould's work by some whose motivation is less than scientific.

Peace.

[omega minimo]

20. There will be a future synthesis

of all the concepts in this fascinating dialogue, including the metaphysical or religious ones. We are the ants in the ant farm, arguing over whether our progress is due to the twist and turns in the tunnels, or to the force that provided sand to dig in.

"The blueprints analogy starts to fall apart quickly when we consider that gene expression is a dynamic, not static, process and cannot be understood well in isolation from the living organism."

This is a really profound and central idea that is overlooked in the argumenst b/w the two "sides" of science vs. faith. The Dynamic is the force that drives the process. It "cannot be understood well in isolation from the living organism." The mechanistic view vs. the Old Man In The Sky belief depends on pitting the dynamic force against the organic process. (Doesn't the New Physics help in integrating consciousness into the mix?)

This is the meaning of my other cryptic (and I hope not unwelcome) post. That Dynamic is the Mystery of Life. Out of the current arguments over creationism, intelligent design and evolution will come a recognition that there is a blind spot in the either/or approach.

That time will come about the time we find the Theory of Everything. :rofl:

:popcorn:

[BillZBubb]

5. PE

The genetic code allows for some pretty sudden and dramatic changes in structure. No reason to believe nature didn't use that.

[omega minimo]

7. I'll take Cognitive Dissonance for $500, Alex

I foresee a time when arguments of mutual exclusivity are obsolete.

[Maple]

8. Scotch

Neat, thanks.

3 fingers in fact. :eyes:

[omega minimo]

9. Trying to get your equilibrium punctuated?

[Maple]

11. No, anesthatized

[longship]

10. Not an either/or thing. But I like punk eek.

The scientific debate is not either/or, but the weighting of the roles played by punk eek and gradualism.

[wli]

12. Punctuated equilibrium

Gould got his evidence together, so there it is.

[greyl]

13. What the... Where is one exposed to gradualism and punct. eq?

Other than the Science Forum at Du, I mean... :)

Hmm?

But based on the words, and not doing any web searches I swear, I'd have to ask "with respect to what?" Puncuated Equilibrium sound more exciting, and seems like it may be an intimate relative of the idea that Dynamic advances need Static latches to prevent regression.

Or are those terms just describing tiptronic transmissions? ;)

(off to learn now...

[mainegreen]

14. Depends on what the environment is doing.

[Ediacara]

16. Both

Proponents of extremes don't listen to the opposite extremes. The pattern seen by punc-eq is real. Morphospecies stay roughly static over time, then rapidly change to something else. This is seen in fossils (which are generally astoundingly complete, contrary to popular opinion), and in lab and field experiments.

The difference of opinion is on the process that leads to that pattern. Punc-eq proponents point to founder events, bottle-necking, and peripatric (groups on the periphery of a large population that has lots of gene flow) speciation as the mechanisms of rapidity, and gene flow as the mechanism leading to stasis.

Gradualists point out that larger populations have a larger rate of mutation, so shouldn't actually appear to be static if gene flow is occuring. They point out that many morphological features are changed at thresholds, so the rate of genetic change is linnear, but morphological change looks jumpy.

So what it looks like is this: "traditional" punc-eq mechanisms seem to be dominant in small populations, like those experiencing founder events, and especially those speciating peripatrically. In large populations, step-wise, punctuated, non-speciation events are dominated by genetic threshold crossing events (which look punctuated, but are essentially gradual in nature).

For two really pretty cool books (although Levinton's is dry as toast), check out:

Macroevolution- Pattern and Process by Steven M. Stanley, and Genetics, Paleontology, and Macroevolution by Jeffrey S. Levinton.

[hunter]

17. Evolution is built into the kit, and not entirely "random."

The word "mutation" implies there is some pre-existing plan. But there really isn't a plan. God's not sitting at His computer terminal today designing DNA.

There are populations of organisms that have "evolved to evolve" when their environment changes, and populations of organisms that are more conservative.

Populations of organisms that are too conservative when their environment changes become extinct. Judging by the incredible diversity of life on earth, nature tends to favor organisms that evolve.

[slackmaster]

19. I believe both processes occur

A little of this, a little of that, an occasional disaster to stir things up.