Punctuated Equilibrium

[TheBeardedDude]

For the most part, any discussions on evolution on this and every other forum I read are centered around gradualism (the primary concept devised by Darwin and furthered primarily within evolutionary biology). In a gradualism scenario all populations are in perpetual transition from previous generations to future generations. That is evolution is a step by step process that occurs every generation very slowly that eventually results in what we would classify as a new species. This most certainly occurs in species that exist today and in the past but it is not the only possibility. There exists Eldredge and Gould's concept of Punctuated Equilibrium and Coordinated Stasis. (It should also be noted that in the case of gradualism, changes in allele frequency are the primary measure of change. This is not the case in paleontology, which is important to understand for punc eq).

In this scenario a species will exist for a geologically significant amount of time in stasis (that is with little or no morphologic change. Punc Eq can't take into account changes in allele frequency since that can't be measured from fossils). There may be some variation through time but the overall change is negligible (some variation about a mean. An example would be the average test scores in any given introductory class in college. Some years it will be higher and some years, lower. But the average is relatively constant). Good examples include some trilobites, bivalves, gastropods and numerous other invertebrates (I am more familiar with the invertebrates so I will stick with them). These periods of stasis are interrupted by some punctuation event. This event could be an increase in the rate of climate change (such as the formation of ice on Antarctica or the rapid release of large amounts of methane gas from the destabilization of methane clathrates). These events induce a rapid speciation event (rapid would still mean several generations that appears in the geologic record as nearly instantaneous). The reasons are fairly simple. 1) If you are well suited to your environment then there is no need for any major changes. This would mean that species would prefer stasis since it would be the most cost efficient method in terms of energy use in a relatively stable environment. 2) Any sufficiently large population would have such a large gene pool that shifting the population in any one direction under normal conditions would be nearly impossible (you can show that with allele frequencies if you fancy an example. It's why genetic diseases aren't selected out of a population entirely). In order to change a large population it needs to be reduced (an extinction event like a large bolide impact for example) or separated spatially (like being geographically separated by an ocean/mountain chain/river/etc...). Once the size of the population is reduced and the size of the gene pool is shrunk, change can occur more rapidly (I am a geologist so rapid for me is still a pretty dadgum long time).

I just want to see what you guys think or know about stasis and Punctuated Equilibrium.

 

[Loudmouth]

Languages may serve as a good analogy. We can imagine two similar ways that languages can change over time. First, a well established population speaks the same language over time and small differences enter in from one generation to the next. Second, there is a great diaspora and the population spreads quickly into new lands where they become isolated from one another. In this instance, we get a bunch of different changes in different populations which greatly increases the number and kinds of variations in that language. A more specific analogy could be the evolution of English within within Britian and the production of many different dialects as a result of British colonies spreading over the globe. Historically, we can see the same thing happening with Latin.

As to biology and evolution, I don't think you have to say that it is either gradualism or punk eek. Both mechanisms are going to be chugging away, it is just matter of which mechanism is most dominant in any given example. What I find most amusing is that some creationists think that punk eek and evolution are two different things. They aren't. Punk eek is just a mechanism within the theory of evolution.

 

[TheBeardedDude]

Languages may serve as a good analogy. We can imagine two similar ways that languages can change over time. First, a well established population speaks the same language over time and small differences enter in from one generation to the next. Second, there is a great diaspora and the population spreads quickly into new lands where they become isolated from one another. In this instance, we get a bunch of different changes in different populations which greatly increases the number and kinds of variations in that language. A more specific analogy could be the evolution of English within within Britian and the production of many different dialects as a result of British colonies spreading over the globe. Historically, we can see the same thing happening with Latin.

As to biology and evolution, I don't think you have to say that it is either gradualism or punk eek. Both mechanisms are going to be chugging away, it is just matter of which mechanism is most dominant in any given example. What I find most amusing is that some creationists think that punk eek and evolution are two different things. They aren't. Punk eek is just a mechanism within the theory of evolution.

 

[keith99]

Punctuated equilibrium makes sense to me.

With the caveat already mentioned that 'fast' is fast in geologic terms, which is pretty darn slow.

Also I see no reason why it should be considered one or the other. No reason why there wouldn't be increased adaption when there is an underlying change to the environment, even if that change is not especially fast.

One other interesting thought is that while there will be some events that impact all species there can also be events that impact only one or a few species. Introduce one new predator and the impact on existing predators it competes with and the prey in question will be far greater than most plants and many other animals.

 

[Loudmouth]

It is worth mentioning that even Darwin described punk eek as a possible mechanism:

"Only a small portion of the world has been geologically explored. Only organic beings of certain classes can be preserved in a fossil condition, at least in any great number. Widely ranging species vary most, and varieties are often at first local, -- both causes rendering the discovery of intermediate links less likely. Local varieties will not spread into other and distant regions until they are considerably modified and improved; and when they do spread, if discovered in a geological formation, they will appear as if suddenly created there, and will be simply classed as new species."--Origin of Species

 

[CabVet]

Problem is that many creationists (and a lot of people that don't understand science in general) think that punctuated equilibrium is the same as catastrophism, and they couldn't be more wrong.

 

[Coelo]

think that punctuated equilibrium is the same as catastrophism, and they couldn't be more wrong.

There is always a mass extinction before you have a population explosion. Although I suppose mass extinction is not considered to be catastrophic.

 

[sfs]

These periods of stasis are interrupted by some punctuation event. This event could be an increase in the rate of climate change (such as the formation of ice on Antarctica or the rapid release of large amounts of methane gas from the destabilization of methane clathrates). These events induce a rapid speciation event (rapid would still mean several generations that appears in the geologic record as nearly instantaneous).

I don't recall anything in Gould and Eldredge, at least in their original paper, about events changing the environment. Rather, their argument was that selective pressures would be different on the periphery of the main population, and therefore different traits would be adaptive there. Since the small population would be easy to miss in the fossil record, no trace would usually be preserved of the speciation process.

The reasons are fairly simple. 1) If you are well suited to your environment then there is no need for any major changes. This would mean that species would prefer stasis since it would be the most cost efficient method in terms of energy use in a relatively stable environment. 2) Any sufficiently large population would have such a large gene pool that shifting the population in any one direction under normal conditions would be nearly impossible (you can show that with allele frequencies if you fancy an example. It's why genetic diseases aren't selected out of a population entirely).

I don't understand the idea that large populations will respond so slowly to selective pressures that adaption will seldom happen there. (The idea appears in Punc Eq paper, too.) Yes, positively selected alleles will take longer to go to fixation in a large population, simply because it has farther to go, but the dependence is logarithmic with population size. Large populations also have more genetic diversity for selection to act on, both standing diversity and new mutations, however, which in many cases should more than offset the slightly longer fixation time, since the diversity is linear in population size.

I also don't understand your point about genetic diseases. Deleterious genetic diseases exist for three reasons: 1) Some deleterious alleles are recessive and not exposed to selection at low allele frequencies; 2) selection doesn't eliminate very rare deleterious alleles quickly, since genetic drift dominates for rare alleles; and 3) new deleterious mutations continue to arise to take the place of ones eliminated by selection (leading to mutations-selection balance). None of these effects is dependent on population size to any appreciable extent.

 

[sfs]

There is always a mass extinction before you have a population explosion.

No, there isn't.

 

[Coelo]

No, there isn't.

"[FONT=TitilliumRegular, Arial, Helvetica, sans-serif]this mass extinction made room for the Cambrian explosion"[/FONT] Top 10 Mass Extinctions - Listverse

 

[sfs]

"[FONT=TitilliumRegular, Arial, Helvetica, sans-serif]this mass extinction made room for the Cambrian explosion"[/FONT] Top 10 Mass Extinctions - Listverse

Mass extinctions leave many ecological niches open, meaning survivors can diversify rapidly to fill them; this is an example of an adaptive radiation. An adaptive radiation is not a "population explosion", which is what you called it; it's an increase in diversity for some clades, replacing lost diversity from other clades, not an increase in the total number of organisms. Nor is a mass extinction the only thing that can lead to an adaptive radiation (which your comment implied): when arthropods moved onto land, for example, they diversified greatly, but the diversification had nothing to do with a mass extinction.

 

[Coelo]

An adaptive radiation is not a "population explosion",

A radiation is an explosion. Just a different word for the exact same thing. It does not matter to me at all. If you want to use the word radiation, then use the word radiation.

 

[sfs]

A radiation is an explosion. Just a different word for the exact same thing.

No, "adaptive radiation" and "population explosion" are are different terms for different things. Just because you're not familiar with their meaning doesn't mean no one else is. (And since I just told you what the difference was, it's pretty, um, remarkable that you still think they're the same thing.)

It does not matter to me at all. If you want to use the word radiation, then use the word radiation.

Well, no, I don't suppose it does matter to you. It does matter to biologists, however, who get kind of confused when you try to use the wrong biological word.

 

[Coelo]

No, "adaptive radiation" and "population explosion" are are different terms for different things.

Yes a radiation and a explosion are different. Yet Wiki says: "The Cambrian explosion, or Cambrian radiation, was the relatively rapid appearance, around 542 million years ago, of most major animal phyla, as demonstrated in the fossil record" So when you see the word "OR" than they are BOTH valid choices as to what happened at that point in time. What happened was an explosion and a radiation.

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

 

[sfs]

Yes a radiation and a explosion are different. Yet Wiki says: "The Cambrian explosion, or Cambrian radiation, was the relatively rapid appearance, around 542 million years ago, of most major animal phyla, as demonstrated in the fossil record" So when you see the word "OR" than they are BOTH valid choices as to what happened at that point in time. What happened was an explosion and a radiation.

The Cambrian Explosion is the name of an adaptive radiation (or multiple adaptive radiations). The fact that it is named "explosion" does not mean it was a population explosion, which is the increase in size of a population.

 

[Prophet 2033]

stasis and Punctuated Equilibrium is what the Apostle Paul warned Christians about: "Science, falsely so-called."

God personally says in the book of Job, chapter 40, that the Sauropod Dinosaurs were created on the same day man was created. Look at the Sauropod family of dinosaurs (meaning "terrible lizards") and you will see that God details them as created, not evolve creatures, in Job 40.

The "Punctuated Equilibrium" theory by the Harvardite Evolutionist was formulated because the fossil record show dinosaurs and all other species showed up suddenly, instantly, not over millions and millions of years.

Stasis, gradual evolution over time, is just the opposite of what the fossil record shows.

 

[Cheeky Monkey]

stasis and Punctuated Equilibrium is what the Apostle Paul warned Christians about: "Science, falsely so-called."

God personally says in the book of Job, chapter 40, that the Sauropod Dinosaurs were created on the same day man was created. Look at the Sauropod family of dinosaurs (meaning "terrible lizards") and you will see that God details them as created, not evolve creatures, in Job 40.

I'm really not sure what a poem from around the 5th century BCE has to do with dinosaurs or evolution and I really really don't know why we should care.

The "Punctuated Equilibrium" theory by the Harvardite Evolutionist was formulated because the fossil record show dinosaurs and all other species showed up suddenly, instantly, not over millions and millions of years.

Presumably you are simply ignorant of the facts rather than lying. Suffice to say this story is not true.

Stasis, gradual evolution over time, is just the opposite of what the fossil record shows.

No it isn't, a review of the evidence seems to indicate that around 20% of speciation is puncuational in nature Large Punctuational Contribution of Speciation to Evolutionary Divergence at the Molecular Level

 

[Justatruthseeker]

For the most part, any discussions on evolution on this and every other forum I read are centered around gradualism (the primary concept devised by Darwin and furthered primarily within evolutionary biology). In a gradualism scenario all populations are in perpetual transition from previous generations to future generations. That is evolution is a step by step process that occurs every generation very slowly that eventually results in what we would classify as a new species. This most certainly occurs in species that exist today and in the past but it is not the only possibility. There exists Eldredge and Gould's concept of Punctuated Equilibrium and Coordinated Stasis. (It should also be noted that in the case of gradualism, changes in allele frequency are the primary measure of change. This is not the case in paleontology, which is important to understand for punc eq).

In this scenario a species will exist for a geologically significant amount of time in stasis (that is with little or no morphologic change. Punc Eq can't take into account changes in allele frequency since that can't be measured from fossils). There may be some variation through time but the overall change is negligible (some variation about a mean. An example would be the average test scores in any given introductory class in college. Some years it will be higher and some years, lower. But the average is relatively constant). Good examples include some trilobites, bivalves, gastropods and numerous other invertebrates (I am more familiar with the invertebrates so I will stick with them). These periods of stasis are interrupted by some punctuation event. This event could be an increase in the rate of climate change (such as the formation of ice on Antarctica or the rapid release of large amounts of methane gas from the destabilization of methane clathrates). These events induce a rapid speciation event (rapid would still mean several generations that appears in the geologic record as nearly instantaneous). The reasons are fairly simple. 1) If you are well suited to your environment then there is no need for any major changes. This would mean that species would prefer stasis since it would be the most cost efficient method in terms of energy use in a relatively stable environment. 2) Any sufficiently large population would have such a large gene pool that shifting the population in any one direction under normal conditions would be nearly impossible (you can show that with allele frequencies if you fancy an example. It's why genetic diseases aren't selected out of a population entirely). In order to change a large population it needs to be reduced (an extinction event like a large bolide impact for example) or separated spatially (like being geographically separated by an ocean/mountain chain/river/etc...). Once the size of the population is reduced and the size of the gene pool is shrunk, change can occur more rapidly (I am a geologist so rapid for me is still a pretty dadgum long time).

I just want to see what you guys think or know about stasis and Punctuated Equilibrium.

Agreed, a dynamically electrically active universe is indeed your best chance of ever explaining any sort of evolution. Chemical bonding is an electrostatic event. Great fluctuations of electric current would cause reforming of the chemical and genetic bonds. Plasma pinches - a naturally occurring phenomenon in plasma - not only produce electric voltage differentials capable of altering chemical compounds, but produce radiation from x-ray to gamma rays, also believed to be a cause of evolution.

Z-pinch - Wikipedia, the free encyclopedia
Pinch (plasma physics) - Wikipedia, the free encyclopedia

Pinches may also become unstable,http://en.wikipedia.org/wiki/Pinch_(plasma_physics)#cite_note-11 and generate radiation across the electromagnetic spectrum, including radio waves, x-rayshttp://en.wikipedia.org/wiki/Pinch_(plasma_physics)#cite_note-12 and gamma rays,http://en.wikipedia.org/wiki/Pinch_(plasma_physics)#cite_note-13 and also neutronshttp://en.wikipedia.org/wiki/Pinch_(plasma_physics)#cite_note-14 and synchrotron radiation.

It is unreasonable to assume our solar system has been stable for millions of years. Mankind himself has myths of what they termed gods being born (planets ejected from the Sun) and ruling in the sky for a time before they went away. One god ruling the sky till the next was born and overthrew him. From the birth of Uranus and his reign until the birth of Saturn. From Saturn's reign until the birth of Jupiter and his brothers, Neptune and Pluto. Then they too faded into the distance. But all caused war in the heavens with great bolts of fire and lightning being cast about the heavens and unto and between Earth, Mars and Venus. I believe actual witnessed events just described by a non-scientific minded society as gods.

This energy release brought about the rise of civilization, your final link from modern man to whichever you finally decide is the previous link. Large plasma events occurred, releasing more energy and radiation than your theories could ever account for by ignoring these events.

It really is your best bet. Would even explain the rise of religion.

Symbols of an Alien Sky | Official Movie - YouTube

 

[Split Rock]

stasis and Punctuated Equilibrium is what the Apostle Paul warned Christians about: "Science, falsely so-called."

Sounds more like creationism to me.

God personally says in the book of Job, chapter 40, that the Sauropod Dinosaurs were created on the same day man was created. Look at the Sauropod family of dinosaurs (meaning "terrible lizards") and you will see that God details them as created, not evolve creatures, in Job 40.

I don't see any "Sauropod Dinosaurs" mentioned in Job 40. You're not adding to scripture... are you?

The "Punctuated Equilibrium" theory by the Harvardite Evolutionist was formulated because the fossil record show dinosaurs and all other species showed up suddenly, instantly, not over millions and millions of years.

Instantly in geological terms, and in some cases, yes.

Stasis, gradual evolution over time, is just the opposite of what the fossil record shows.

No, the fossil record shows both.

 

[Coelo]

The "Punctuated Equilibrium" theory by the Harvardite Evolutionist was formulated because the fossil record show dinosaurs and all other species showed up suddenly, instantly, not over millions and millions of years.

The first (carnivore) dinosaur was around 250 million years ago. The Cambrian began around 550 million years ago where we see the beginning of hard shells that show up in the fossil record. Trilobite fossils for example are very common. Actually the dinosaur bones are very common also. They have places where they have already found over 100,000 of them. If you study the different events that have taken place at different points in time, there does seem to be a pattern emerge.