I’m sorry, I just can’t understand this whole idea of “punctuated equillibrium”.
I need info. on this! Because, as I understand it…They are basicly trying to say that; once upon a time, an alligator layed an egg and a bird hatched.
If someone can explain it better…PLEASE DO!
Yes, Jedi, you ARE misunderstanding this. What “they” are saying is that the genetic isolation which is speciation most often occurs in peripheral populationa of a species. That is, groups at the fringe of the species normal range.
The edges of a species’ range have slightly different environments than the central part of the range. That is, obviously, why the species has reached its limit at that point; their adaptations which work well enough in the bulk of their range do not quite fit elsewhere.
Now, a small population can get seperated from the main population by any number of mechanisms. For simple matters, a river might change course or a patch of forest could get cut off from the main body. The population thus seperated will adapt to the slightly different environment, developing the characteristics which enable them to survive in an area which was only marginal for the main population.
When the new splinter group comes into contact with the original population, they may have developed in enough details to preclude interbreeding with the originals. They are then a new species, related to the parent stock but operating in a slightly different niche. Because they are now breeding seperately from the main population, selection pressures and simple genetic drift will tend to make them even more different than their parent stock.
Because we are looking at small populations adapting rather quickly (in geological time) the chances of us finding a fossil from the split off population are very slim. If the new species is viable, they will colonize their own range and when they build up a respectable population they may leave a few remains of individuals to be fossilized.
Large populations change slowly. This is what is referred to as “stasis” is the fossil record. Small populations change quickly, but are less likely to have any individuals die in the right circumstances to be preserved. The result of this is that new species appear “suddenly” in the fossil record, but only because the mechanisms of speciation are operating at a speed which usually causes them to fall between the resolution of the fossil record.
If you need any more clarification, don’t hesitate to ask.
Dr. Fidelius, Charlatan
Associate Curator Anomalous Paleontology, Miskatonic University
“You cannot reason a man out of a position he did not reach through reason.”
Mynd you, møøse bites Kan be pretty nasti…
Exceptionally good definition, Dr. F. You win the Gould Medal! 
Once again, I’m forced to wonder exactly where Jedi got his “science” education…
I vote for home schooling.
The ARG Institute of Advanced Learning?
Now there’s a contradiction in terms!
I don’t recall encountering Jedi-667 (across the Street from The Beast!) previously. This may be due to my inattention or to his posting on threads which have not caught my interest. Does anyone have a link to a thread that gives me a little insight on this person?
Thank you.
DrF, please give a big welcome to Jedi-667, who signed on this morning.
Jedi-667 lists his\her interests as “Any type of science (esp. Creation).”
This space for rent.
Wow… A Creation Scientist signed up… This ought to be fun…
:: getting popcorn ::
Yer pal,
Satan
DrF – the first message of his that I encountered was in the thread, “You’re not a good Christian” but I moved my response to “The Big Bang.” So you can see him there.
Although, considering your recent performance, I wouldn’t be surprised to find out that he is actually a regular trying to outdo you.
Okay, that explains it. I got bored with “You’re not a Good Christian” even before the jodih exchange. I realized that I am not a “good Christian” by anyone’s definition (the expectations are rather steep), so I’ll continue to try my best to be a “good man” and take it up with the Judge when it is my time.
Welcome, young Jedi. Don’t let attitudes bother you here, manny of our regulars tend to be a little cynical and snide. We all have our strengths and weaknesses but on the whole we try to give out accurate information. Usually. If we feel like it.
While not in contradiction of the previous explanation, I would like to offer the following additional expansion on the punctuated equilibrium theory of natural selection. DNA exchanges create natural mutation at a more or less stead rate, and those events cause species to exhibit characteristics not in common with other members of the species. The overwhelming majority of such mutations are either not inheritable (prevent subsequent fertilization, or selection of that specific chromosome during the creation of gametes) or so small a difference, that no specific change in the species is likely. Among the more dramatic differences, unfavorable changes are less likely to be saved, except in habitats so rich and comfortable that competition is very weak. The total number of variations comprising the entire genome of a species grows over time, until some event or series of events alters the characteristics of the habitat of the species being considered.
When that occurs, the characteristics of each individual member of the species undergoes a natural selection, this will occur far more rapidly than the normal accumulation of small changes. When temperatures drop by a half dozen degrees, the ability to digest less nutritious foods is not a minor variation, but a major survival benefit. Among the species as a whole, those specific individuals are much more likely to survive, and produce progeny. That is enough of a difference to change the genome of the entire species in some locations, to include only ancestors with one particular set of characteristics, and whatever other characteristics that population might have. That can occur in only a few generations, if the pressure on the environment is severe. Twenty years, two hundred years, two thousand years, and immediate are identical time periods, in geological terms.
<p align=“center”>Tris</p>
Return of the Jedi-667 wrote:
In the 4th grade, we read a kid’s book titled The Enormous Egg, in which a chicken laid an egg and a Triceratops hatched out of it. (Based on the incorrect theory that, since chickens evolved from dinosaurs, chickens must therefore be carrying the entire dinosaur genome within them.)
Does that count?
Oooooh! I remember that one, Tracer! IIRC, the kid who found the egg got to walk it around on a leash.
Come to think of it, I had a fried egg the other day that had scales in it. I thought it was just a really awful diner. But it just might have been the missing “chicken to aligator” link.
-andros-
Another great scientific discovery goes down the tubes!
Er, walk the dinosaur around on a leash, that is. 'Course he could have taken his egg for a drag, I guess.
>>>Because we are looking at small populations adapting rather quickly (in geological time) the chances of us finding a fossil from the split off population are very slim.<<<
So the evidence for this theory is that there is no evidence for this theory, right?
LONESOME POLECAT
+++++++++++++
When the pin is pulled,
Mr. Grenade is no longer
our friend.
Um, no Polecat. Not right.
That was great book! Did you read the sequel, where the same kid who owned the chicken goes to France on an archeological dig, and finds a living caveman?