Pack Rat Middens Give Unique View On Evolution And Climate Change In Past Million Years

Science Daily ^ | 10/31/03 | Cal Berkeley

[I Am Not A Mod]

Threads on related topics have been going better recently. Let's keep it that way.

[Just mythoughts]

"I Am Not A Mod" either but this article demonstrates how "evolution" as taught in classrooms from single cell to apes to "man" is not the case.

No matter how many years described a "vole" is still a "vole" and the only thing about the "vole" that is described in "evolving" is their teeth.

[Just mythoughts]

"I Am Not A Mod" either but this article demonstrates how "evolution" as taught in classrooms from single cell to apes to "man" is not the case.

No matter how many years described a "vole" is still a "vole" and the only thing about the "vole" that is described in "evolving" is their teeth.

[f.Christian]

[MEG33]

Think the word adaptation would take the sting out of the evolution word?

[Miss Marple]

I think everyone is missing the real point of this study, which is buried in the middle of the article:

"It's likely that speciation takes place over a longer time interval than extinction," Barnosky said. "So, climate changes like the global warming we are seeing today are probably happening too fast to cause anything but extinction."

There you have it. Global warming is a fact, and it is going to cause massive extinction. (And of course it's all George Bush's fault.)

[f.Christian]

" I'll believe in evolution when my desire alone for a whole lot of money is enough to be matched by an anonymous spontaneus billion dollar deposit in my checking account "

paraphase quote of gore3000 !

Isn't that liberalism ... money trees - magic ---- wishfull reality - thinking ?

[MEG33]

Global warming is a natural fact.That any thing we could have done or might do to slow it is unlikely and certainly not proven.

[Wonder Warthog]

"In light of the slow pace of speciation and today's rapid climate change, these findings hold a sobering lesson, Barnosky said."

One can't have a science article, it seems, without the "obligatory" propaganda about global warming.

[balrog666]

Fuzzy speciation - just as science predicts - ping.

[Ahban]

Because fossils of the sagebrush vole are not found before the species appears full blown in Porcupine Cave, Barnosky thinks that the sagebrush vole had only recently evolved.

So we've a sudden appereance of a type followed by such tiny amounts of change that it is impossible for the scientits to tell whether modern voles are a new species, or just a subtype of the voles of 1 million years ago.

This rate of change is woefully inadequate to explain the fossil record. There have probably been over one million new FAMILIES of creatures appear since the first wave of animals arrived in the Cambrian Explosion. That is one new FAMILY every 435 years. This article is another example of my contention that evolution, to the extent it happens, does not happen fast enough or cause change enough to explain the fossil record.

[Alamo-Girl]

Thanks for the heads up!

[CurlyDave]

In the last 10,000 years, however, the original vole has disappeared entirely...

Please note that this species, as well as 99.9% of other extinct species, disappeared without any influence of the National Rifle Association, urbanization, pollution, etc.

It is natural for species to die out and our attempts to prolong this process through environmental impact reports and other such nonsense only serves to breed a larger and more well-funded set of bureaucrats (evolution in action) who impose increasingly onerous regulation on the rest of the population.

[Physicist]

Together, these snapshots show very gradual change in the sagebrush vole, Lemmiscus curtatus, as the climate goes through one of many periodic cycles of glacial advance and retreat, with the original vole population coexisting and probably interbreeding with its evolving cousins.

However, a major climate alteration about 800,000 years ago dramatically shifted the population balance toward the evolving vole and away from the original vole population.

The original vole population still took about 800,000 years to die out, because it lived as recently as 9,500 years ago. Sediments of that age in a Nevada cave still contain the animals' fossilized teeth. In the last 10,000 years, however, the original vole has disappeared entirely, leaving the new variant that continues to evolve away from the original.

This science writer doesn't seem to have a very good idea of how evolution works. The two populations of voles will evolve at roughly the same rate; it's not true that one population will evolve while the other remains the same. At any given moment, the two populations will be (approximately) genetically equidistant from their last common ancestor.

What they mean is that one population specialized in such a way that their teeth became mophologically different from the parent stock, while the other population's teeth looked about the same as those of the parent stock.

[Dimensio]

No matter how many years described a "vole" is still a "vole" and the only thing about the "vole" that is described in "evolving" is their teeth.

This does not disprove evolution. Evolution does not predict that species will necessarily disappear over thsouands of years.

[VadeRetro]

So we've a sudden appereance of a type ...

Ten layers got studied. The oldest layer has some variation already. Are you assuming the oldest layer studied is a "sudden appearance?" Why?

I see no "sudden appearance" in this article.

This study seems to have been modeled on Gingerich's survey of Pelycodus, which also showed gradual change accumulating steadily.

[Ahban]

The words "sudden appearance" are not in the article, but this is....

"Because fossils of the sagebrush vole are not found before the species appears full blown in Porcupine Cave, Barnosky thinks that the sagebrush vole had only recently evolved. "

....that is the same thing, in so many words.

The timescale for divergence in your graph is also too great for those mechanisms to explain the great diversity in the fossil record, unless those mechanisms also operate much, much, much faster than in these two examples. Its what, 1.6 million years total, with 90% of the divergence showing up in the last half million? That is still a long time for such a small difference.

On an issue unrelated to our disagreement, I noticed something odd about your diagram. I find it intersting that the data breaks toward the right, until one branch snaps back to the left, with another branch veering even more sharply right. I wonder if that pattern is consistent in other examples?

That would be consistent with the idea of a changing environment pushing a species from one niche into another. Say a species is fit for its niche. It is not "pulled" in any direction sofar as morphological change goes. As they exploit the new niche (along with the old one) for generations they are "pulled" in two directions, trending towards fitness in the new niche.

Eventually, the "pulling" of fitness for two niches results in a split, with one group quicly returning to its orginal starting point, and going back to its old niche (if it still exists). The other group, better adapted now to the new niche than the old, accelerates over into its new niche, now that it is no longer being dragged back to the mean by the "pulling" effect of exploiting two niches.

[VadeRetro]

"Because fossils of the sagebrush vole are not found before the species appears full blown in Porcupine Cave, Barnosky thinks that the sagebrush vole had only recently evolved. "

My sloppiness; I didn't register that. I should mention that while Barnosky says the sagebrush vole was pretty new at its appearance in the cave (presumably because there are no older fossils known elsewhere either), this is because prior divergence happened at some distance from the cave at some site not excavated or maybe not even preserved by fossilization. (Some places have deposition, some places have erosion.)

Eventually, the "pulling" of fitness for two niches results in a split, with one group quicly returning to its orginal starting point, and going back to its old niche (if it still exists).

Sounds like you are discovering the sympatric model of speciation. That's thought to happen in some cases, although it's perhaps not the most important model. (The model most often described on these threads is the allopatric one with geographic separation between sub-populations.)

Modes of Speciation.

[Just mythoughts]

"Evolution" does not prove anything it is a theory.

Now it is written that "man in the flesh" will someday be extinct. So stay tuned and "time" not evolution will reveal what will happen.

[Just mythoughts]

"adaptation" versus "evolution" no sting in either word if they are defined in what they mean.

The "stretch" that some use to make each word cover what one believes has lost its elasticity. A "theory" is not scientific data, rather what some use to explain the data, their own interpretation.

Fact this "earth" is more than "six thousand" years old.