THE END OF EVOLUTION?

They understand the cell very well.What they may speculate on is the origin of it but that's still an open science. A lot of work has been put into the field of abiogenesis and there's no reason to believe that this one area of science will never be fully understood. No we are not. We are talking about one cell on Earth, whether or not it is the most complex structure in the universe seems a bit presumptuos and unverifiable.Are you willing to go out on a limb and say it is the "most complex structure in the entire universe"...? Really?The cell is complex, I will not doubt you that, it is complex to us. But we have nothing else to compare it to so it is complex in comparison to what? They are complex, to you they must seem so highly complex that their very existance is baffling to you, but I can assure you that to a cell biologist the cell is simply another organized structure found in nature, and it's origins are of natural order, as is everything elses found in nature.What reason do you have to doubt this, and what evidence are you using to support that reason?

---

"I smoke pot. If this bothers anyone, I suggest you look around at the world in which we live and shut your mouth."--Bill Hicks"I never knew there was another option other than to question everything"--Noam Chomsky

We do have people from 10000 years ago or 6000 years anyway, us, our cells have been copying themselves, just like the chimpanzees and the pandas, the wolves and any other kind of animal.

---

There no doubt exist natural laws, but once this fine reason of ours was corrupted, it corrupted everything. blz paskal

But not perfectly. That's where the E-word sneaks in, Lucy.

I assume by the E word you mean Entropy. Inescapable, sure, that's what makes the cell such a miraculous instrument, it has inbuilt knowledge of what it has to do.

---

There no doubt exist natural laws, but once this fine reason of ours was corrupted, it corrupted everything. blz paskal

I'm not sure in what way you're misunderstanding what I said, so let me say it again in a slightly different way. There is no one alive from 10000 years or 6000 years ago or even 200 years ago, so we cannot perform an actual fertility test where an actual sperm fertilizes an actual egg.That's why I said we'd have to rely on a less-than-conclusive genetic analysis. There's not really any reliable way to tell interfertility just by inspection of DNA that's already very similar.The E-word that Coragyps was referring to is evolution. Cells copy themselves imperfectly, and that is the source of the variation upon which selection operates. Combine the variation produced by descent with modification with selection and you've got evolution.But you're again forgetting the topic. While arguing that evolution isn't possible you made a number of confused claims about 2LOT, entropy and information. Was my explanation in Message 150 helpful?The bottom line is that reproduction is almost always imperfect. A child cell is almost never a perfect copy of its parent, and sexual species even less often produce children that are perfect copies of themselves. The issue for you isn't whether genetic changes (mutations) happen during reproduction, because there can be no doubt that they invariably do. Your problem is that there is nothing that could ever stop them from occurring and accumulating over the generations.--Percy

You need different mutations to accumulate in each population. Think of languages. If two populations continually spoke to each other then any changes to the language that occur in one population will quickly travel to the other. If the two populations do not speak to one another then different changes will occur to the language in each population. Over time these changes can add up to the point that the two populations are no longer able to understand one another. The same thing happens with DNA.

Percy said in post 143 that it is required that genes not intermingle. The salamanders at either end are interbreeding with other groups.You said that the two adjacent groups do not interbreed. Does that mean that they cannot interbreed?

That is exactly what Schneider modeled in his EV program. He looked at a DNA binding sequence and DNA binding protein as the sender and receiver. He then looked at the evolution of this system. He observed that the application of evolutionary mechanisms resulted in an increase of Shannon information.Schneider also discusses how this program produces Complex Specified Information (Dembski's CSI):http://www.ccrnp.ncifcrf.gov/~toms/paper/ev/dembski/

The point is that the genetic flow between the groups is restricted. Their ranges only overlap at the edges. This makes it difficult for a mutation on one side of the ring to make it to the other. Restricted gene flow is what produces divergent populations.

The gene flow from one end to the opposite end is likely exceedingly small. Beats me. That the salamanders in this ring species do not interbreed is sufficient to attest to speciation.

---

Religious belief does not constitute scientific evidence, nor does it convey scientific knowledge.

Hi Alaninnont,A diagram probably makes this easier to talk about. Here's a Google satellite image of the US with the geographical locations of a hypothetical set of closely related species arranged in a ring: A can breed only with B.B can breed with both A and C.C can breed with both B and D.Etc. until you end with I which can breed only with H.In other words, all species can interbreed with species adjacent geographically except for A and I.So gene intermingling occurs between A and B, but not A and I, at least not directly. It is possible for genetic information to be transmitted from A to I via all the intermediate species from B to H, but that would be a very, very slow process. This means there is a high degree of genetic isolation between A and I, and for all intents and purposes their genes do not intermingle.A and I are separate species because they cannot interbreed.A and B can interbreed and sometimes do, but they are not exactly the same species, nor are the they different species. This comes about because evolution is a gradual process. As species become more and more genetically different over time, the likelihood of individuals from the populations being interfertile declines.B can interbreed with both A and C, and again, it isn't exactly the same species as A, and not the same species as C, but nor is it exactly a different species.However, B is less able to breed with D, even less able to breed with E, and so forth. In other words, as the genetic differences increase, so does the degree of interfertility decrease.--Percy

Clearer. Thanks. Is there a situation where A to I are alive today or is this just speculation?I'm a little confused by "they are not exactly the same species, nor are the they different species." How do you define a species? Wouldn't that have to be unable to interbreed to make them different species?Getting back to my original point, I think homo sapiens are the end. We have had incredible opportunities to become a new species with the exponential population growth, competative pressure beyond any homo, environmental stresses that no other homo has been exposed to, mutanogenic substances galore, and still no new species. If it was going to happen, it should have by now.

There are a few, with the greenish warblers of Asia being among the better publicised:
Greenish warblersI can't find the statement anywhere that "the two Siberian species are NOT interfertile." They might be - but it seems a pretty reasonable position that if the birds themselves don't want to cross that mating line, the two can be regarded as distinct species.

Ring species are very real. It's because of their reality that they were introduced into the discussion. They are an illustration of a gradually changing species, with the changes distributed geographically in the here and now, rather than distributed across time in the past. Since all members of a ring species still exist, their living members can be studied extensively, something that isn't possible when all you have is a fossil (though some fossils do exhibit DNA remnants).I don't keep a list of ring species in my head, I have to look it up. Wikipedia has an article on Ring Species, and they provide several examples, and I found several more over at TalkOrigins:

• Larus gulls form a ring of species around the North Pole.
• Ensatina salamanders from a ring around the Central Valley in California.
• As Coragyps mentioned, the Greenish Warbler set of species forms a ring around the Himalayas.
• The deer mouse
• The American bee Hoplitis producta
• The subterranean mole rat, Spalax ehrenbergi
• The Great Tit, Parus major

Ring species were introduced into the discussion to help answer this very question. Sexual species are grouped into species by reproductive boundaries, but some reproductive boundaries are more distinct than others. A cat cannot under any circumstances breed with a dog. Even using artificial semination, cat sperm could never fertilize a dog ova, and dog sperm could never fertilize a cat ova. The reproductive boundary between cats and dogs is very firm.But a lion can breed with a tiger. They're called ligers and tigons. The offspring are almost always infertile and so populations of ligers and tigons can never spring up. So although lions and tigers are mutually interfertile, they are considered separate species because the offspring cannot produce a line of descendants.But the species that compromise a ring species and that are adjacent geographically are not so distinct reproductively. They can not only interbreed, their offspring are often fertile. Hence small hybrid populations are not uncommon at the limits of their ranges where the two species might come in contact with one another.So going back to my diagram, are A and B separate species? It's hard to say. Let's say the fertility of A mating with B is the same as when A mates with A, or when B mates with B. Should they be considered different species just because they have different ranges, behaviors and appearance? Biologists can, and I'm sure do at least occasionally, have long arguments about this.But now let's say that when A mates with C, which is more distant genetically from A than was B, that around 50% of the offspring are infertile. Are they the same species?And when A mates with D, even more distant genetically, lets say that around 10% of the offspring are fertile. Are they the same species?And when A mates with E, F, G, H or I, almost no offspring are ever fertile. They're definitely not the same species.What ring species with their indistinct boundaries illustrate is the gradual nature of evolution. New species do not emerge suddenly. New species are the product of very gradual change over long periods of time. As changes accumulate the emerging species becomes less and less capable of interbreeding with the original species, and at some point those responsible for classification decide that the various differences are sufficient to justify classification as a new species. After absorbing the above, do you still believe this?--Percy

A salamander is a salamander, not a bear. I didn't misunderstand what you said; I just disagree, life is continuous.You seem to make a claim that I don't understand 2Ltd. Edited by LucyTheApe, : No reason given.Edited by LucyTheApe, : No reason given.

---

There no doubt exist natural laws, but once this fine reason of ours was corrupted, it corrupted everything. blz paskal