Might just be earlier maturation/breeding due to less competition for food, but obviously early sexual maturation would be favored by this disease and any genetic variation that promotes such will have differential reproductive success.
Posted on 07/23/2008 6:57:31 AM PDT by Soliton
Here we go again in Kansas, haggling about evolution. In the mean time evolution keeps on happening and in unexpected ways. For example, you may be familiar with the infectious cancer that is threatening the Tasmanian Devil (AKA Taz) with extinction. This cancer is spread when the Devils bite each other's faces during mating leading to spread of cancer cells from animal to animal.
The infectious cancer cells are genetically identical and their spread is believed to be made possible because inbreeding has led to a loss of genetic diversity so that the animal's immune systems are not able to recognize the foreign cancer cells.
See this link for background.
In an interesting twist, natural selection seems to be operating, at least in the short run, to favor precocious sexual activity and breeding. According to the research published in the Proceedings of the National Academy of Sciences, this is the first time where an infectious disease has been shown to bring about these sorts of life history changes in mammals.
(Excerpt) Read more at 2.ljworld.com ...
yawnnnnnnn, more propaganda.....bring it on...someone will believe it....
Might just be earlier maturation/breeding due to less competition for food, but obviously early sexual maturation would be favored by this disease and any genetic variation that promotes such will have differential reproductive success.
Correlation is not cause.
So the offspring of the sexually precocious Tasmanian devils are a new species, and are not Tasmanian devils anymore?
This is not species to species evolution, its adaptation.
Adaptation or genetic mutation does not prove species to species Evolution. That kind of evolution requires a gain of genetic information previously unknown to the organism. A GAIN of genetic information would prove evolution.
Its getting old the articles being trotted out by 'evolutionists' supposedly proving evolution using adaptation as the 'proof' and citing genetic LOSS instead of GAIN.
Show me an organism that has gained genetic information out of nowhere if you want to prove evolution, but please don't give me mutation or adaptations resulting from genetic loss as 'proof' of any kind of species to species evolution.
In the lab a strain on non-citrate digesting e.coli was seen to develop over thousands of generations, the ability to digest citrate, giving them a survival advantage over non citrate digesting bacteria in the flask.
So how is either of these not a gain of information?
Not every genetic change leads to speciation, but any change in allele frequency in a population due to selective pressure is evolution, by definition.
A definition chosen so that evolution can be considered an incontrovertible fact.
If a red haired woman has triplets, all with red-hair, then the frequency of the gene for red-hair has increased in the population. Voila! A woman gives birth, and we see evolution in action.
Weak, pointless definition.
Most likely there’s some sort of methylation involved that is turning on some gene sequences and turning off others. (NOTE: See Larmackism ~ it’s back. It’s called “Epigenetics” these days.)
Darwin used the term before the science of genetics (and therefore the genetic phenomenon of allele frequencies) was discovered.
Obviously we don't gain genes or lose genes to any significant degree, but we do seem to add a little variation to genes, and that doesn't seem to make all that big a difference. The same old proteins get produced and we all continue to have the same organs the first mammals on Earth had. We even have some of the same organs that modern reptiles and birds have!
So, what makes things different from critter to critter? The new field of epigenetics is finding that it's a process called methylation. Here a methyl~ is added to the DNA where the gene is located, and it may turn that section on, or turn it off, or bypass it, or create other apparant changes. Since this is an entirely new science with a new vocabulary, and totally new concepts, you, too, can get in on the ground floor.
The opportunity for contamination in that lab must be enormous unless he's got every one of his 21,000 test jars totally isolated at all times in all ways with virus proof filtering.
Darwin proposed that natural selection would be a driver for evolution. The Tasmanian Devil article is about natural selection in progress. It supports Darwins theory. The article is only indirectly related to speciation.
Disputable. All it shows is yet more adaptation. The adaptation of bacteria to feeding on nylon waste
The this metabolic pathway was seen to evolve from existing e.coli genes and not contamination would you then admit it was evolution or would you have other objections?
How about the nylon digesting bacteria? Was that from “contamination” as well? Contamination with what exactly?
That's odd.
The title says "Evolution In Action" and not "A 'Driver' For Evolution In Action."
I guess accuracy is less dramatic.
Yes, they “adapted” an enzyme capable of digesting an ester through mutation and natural selection until it was “adapted” to digest nylon. This gain of information “adapted” it to live off a new synthetic food source as it has evolved to be a nylon digesting bacteria.
Yes I've just begun to read up on methylation. And the more I read the more I see intelligent design in the process, not evolution. This on/off sequence must occur in the exact right sequence more indicative of design than by chance. JMO. Thanks for the input.
We only have the word of the project leader concerning the level of filtration. Before anyone buys off on that guys study too much we need to have it replicated by a disinterested party.
Bacteria are very adaptable. They swap genes with each other ~ across species ~ if they have species!
And the nylon digesting bacteria? Do you think this was also due to contamination? And contamination with what exactly? There was no survival advantage to having a gene for digesting nylon until humans invented nylon and began to produce it. Obviously something “gained” information, and by tracking it back we find that it gained this information by modifying an esterase enzyme through a two base substitution.
Thinking of another one ~ when did life originate? Obviously it's a pretty old idea and probably pre-dates our particular universe. Got to thinking of this yesterday when I watched an industrial movie about making copper roofing materials. Turns out copper is so toxic to all sorts of critters they just disappear as the copper oxidizes over many years into a nice shade of green.
So, life (as we know it) obviously arose in an environment where there were no toxic metals like copper, or, maybe in a universe that didn't yet have copper, or, that couldn't support heavier elements.
Lot of choices there.
We know there was no copper until the formation of large red giant stars that blew up as super novas, so that takes us back to earlier than the 1st billion years of this universe.
You didn't read the article I posted. The idea there was a 'gain' of information is disputed. There happens to be another viewpoint that the information to 'digest' nylon was inherent already in the plasmids and was thus not 'new' information. Point #1 & #5 stated the following:
"1. There are five transposable elements on the pOAD2 plasmid. When activated, transposase enzymes coded therein cause genetic recombination. Externally imposed stress such as high temperature, exposure to a poison, or starvation can activate transposases. The presence of the transposases in such numbers on the plasmid suggests that the plasmid is designed to adapt when the bacterium is under stress..." 5. .....The rapidity of this adaptation suggests a special mechanism for such adaptation, not something as haphazard as random mutations and selection. ...."
So how is this not a gain of information?
All DNA is “designed to adapt” when under selective pressure; that is why it is subject to evolution.
The primary definition of evolution being a change in allele frequency is used because it is useful. How else would one describe an experiment in the power of natural selection of starvation resistance in fruit flies that made a population capable of 90% survival of a stress that would kill 90% of non starvation adapted population? This was not due to any “new” allele rising in the population, although there is always a chance of that, it was from a change in the frequency of alleles due to natural selection that led to a new trait.
The definition is neither weak or pointless, and as you pointed out, change in allele frequency in response to selective pressure leading to new traits in a species is “an incontrovertible fact”.
There was a short while ~ maybe less than 4 decades ~ where biology held to a belief that the only information in your genome is what our parents gave you, or what arose as a result of a mutation in that genome you inherited. Now we know that methylation exists and has a very powerful influence at both the molecular level and at the macro level. Now that we know about the vast world of free genes in the world ocean (and wherever critters live) the more pressing questions concern how those genes or parts of genes get passed around epigenetically.
Simply acknowledging that the function of the genome can be changed by outside factors we necessarily slip back into a pre-darwinia past when it comes to the language we need to use to 'splain stuff, and boy do we have some stuff here.
Wasn't it Crick himself who upon discovering DNA said "ah, so that's how they did it"? ~ and he wasn't referring to his parents either.
Let me put it this way, if I pull out the old Holly carb in my V8 Chevy Van and replace it with a Fuel Injection system (to do a little street racing, or maybe improve MPG) I am certainly changing the information in that Chevy Van ~ but it's still a Chevy Van, and my adding new parts didn't make Chevy Vans, as a class, "evolve".
If, on the other hand, I came out there some morning and the Holly carb had disappeared and in its place was a Rochester carb, would it be acceptable for me to start hollering "My van evolved"?
Obviously not. There are linkages here. Add one thing, it changes. Deduct another thing, it changes. But, natural selection had nothing to do with it! Rather, as far as Chevy vans go all of the revisions were "epigenetic" in nature!
You have to do something more than to try to grab holt on the word "change" and run about the countryside proclaiming yourself to be the candidate of "change", and the "answer to everything". You've gotta' show us the policies, and the linkages, and maybe even tidy your report up with some references to Van Der Wals force or something equally significant.
Only in your viewpoint. I see a designer if its 'designed' to adapt.
The article is correct, it shows evolution through natural selection. You are confusing evolution in general from speciation
DNA is an exceedingly complex chemical. You can produce double helix molecules thusly: http://www.rsc.org/publishing/journals/CE/article.asp?doi=b508701e
What I don't see is an “Incompetent Designer” who needs to intervene because his design is not capable of effecting the necessary change and so he must utilize miraculous powers to push things the way the Incompetent Designer wants.
So yes, all DNA is potentially subject to selective pressure, and when this pressure results in a change in a trait (such as increased frequency of first year breeding in Tasmanian Devils), that is known as “Biological Evolution through Natural Selection”.
A little contamination here and there, and you've got genetic material that might do almost anything.
So, literally, created from the dust of the Earth (in a manner of speaking).
BTW, I think the term "self assembly" is much more understandable than "natural selection". We can measure it, give numbers to it, evaluate energy flows ~ all sorts of scientific things.
While there is selective pressure for early breeding, this may not be responsible for the rapid change in the timing of breeding. So then these immediate changes are not direct evidence that real evolution of the Devil's life history characteristics is happening here, hence my wish for follow up studies to try to sort the nature of the Devil's response out.
Following Occam's Razor, I think the commenter has the simpler explanation for the observations.
Arguments on CREVO usually go something like this.
C: Evolution is impossible. No gain of information is possible. All evolution is a loss of information.
E: Loss of information is certainly easier and a more common example of evolution, but we see gain of information in citrate+ evolving e.coli and nylon digesting bacteria.
C: That isn't speciation! It is still a bacteria. Speciation has never been observed.
E: No, we see evidence of speciation in ring species. Speciation, even according to the “hard” definition of perfect reproductive isolation, has been observed both in nature and the lab.
C: Species can change according to their “kind”. But that doesn't show that there is common descent.
E: ERV sequences and homology in phylogenetic studies show common descent.
C: This doesn’t show how you got life in the first place!
E: Evolution through natural selection isn't about how life came about, only how life can change due to natural selection of genetic variation.
C: Why do Evolutionists keep changing their arguments?!?!
It may well be a mix of the two factors.
Circumstances may have led to more Devils being able to breed earlier due to less competition for food and mates.
There also quite well may be selective pressure on any and all alleles that lead to faster maturation, size gain, sexual maturation, etc. This type of change has been seen in thousands of studies on selective pressure and it would be no surprise to see that it is happening among the Devils.
Thus allele frequency may be responding to selective pressure leading to the evolution of a ‘first year breeder’ population of Devils.
What is needed is a good analysis of the genetics of the Devils before and after this disease to see what alleles changed frequency and what effect this allelic change would have on the sexual maturation of the Devils.
Same with flowering plants. You find a nice gene in a little periwinkle. You breed it with another plant, and then another plant, and so on, for hundreds of generations, and you can move that nice gene all the way into a giant sequoia.
So, what's the species? What's the individual? How come flowering plants are like a large, multisegmented, complex machine for building starch and protein?
Species don't always fit into a nice category as if things were separated by a designer from the beginning or for the intellectual convenience of humans who like to categorize things as separate unique and distinct and then give them a name; what we see in nature is more as if what worked persists and what didn't work was discarded and we are all related by common ancestry.
Thus a hybrid species of high mountain sage and valley sage may be a mix of both species, a cross between the two different species, or a true breeding strain from two hybrids.
Like walking from a forest down to a swamp. There is no clear line where the forest ends and the swamp begins. Things just keep getting swampier and swampier until you are no longer in a forest, but in a swamp.
No doubt flowering plants, taken as a whole, are a single machine.
INTREP
The only definition I can find for this is intelligence report. What do you mean?
Fact is we haven't got a clue.
How is adaptation not evolution through natural selection, or sexual selection?
How do we know that they haven’t shared a common ancestor in a long time? Phylogenetic analysis. I say we have quite a few “clues”; many thousands of papers on phylogenetic analysis say that YOU may well not have a clue, but Biology has a pretty good idea.
It doesn't produce an entirely NEW species...........
“How is adaptation not evolution through natural selection, or sexual selection?
It doesn’t produce an entirely NEW species...........”
“The various Ensatina salamanders of the Pacific coast all descended from a common ancestral population. As the species spread southward from Oregon and Washington, subpopulations adapted to their local environments on either side of the San Joaquin Valley. From one population to the next, in a circular pattern, these salamanders are still able to interbreed successfully. However, where the circle closes — in the black zone on the map in Southern California — the salamanders no longer interbreed successfully. The variation within a single species has produced differences as large as those between two separate species.”
If you were simply to remove the population in the middle, you would have two distinct, non-interbreeding species. Two species evolving from one through adaptation over time and geography through natural and/or sexual selection just as Darwin had proposed.
http://www.pbs.org/wgbh/evolution/library/05/2/l_052_05.html
That's an incredibly long period of time. All of them have the same nutritional requirement ~ you can buy hydroponics mixes that purport to provide the exact needs of every flowering plant on Earth (depending on plant age since that will adjust needs). Presumably the very first flowering plants had the same requirements.
Like the 28,000 (or so) genes in mammals, the nutritional requirements of flowering plants are stable over geologic time scales.
To maintain structural integrity over such a long period of time something must be at work very much like a "field". Else, "change" would have led the plants and the critters into wild paroxysms of variation. So, where is the "field" ~ is it in one of he tiny wrapped-up extra dimensions perhaps?
They’ll still all have the same genes ~ 1 to 1 correspondence in fact.
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.