Ready When Made

No, he doesn't have a good point. And nor do you. Essentially your argument relies on assuming rapid climatic changes frequently reversing beyond the point where they can be tracked by evolutionary processes. Well if you could provide evidence that this is that actual state of affairs then you would have an argument.
Of course, it obviously isn't the case so your point rests on an assumption that is clearly false.

Doesn't macroevolution take many tens of thousands of years on average? Well, the climate can reverse pretty fast. In several centuries you can get vast climatic variation such as the small ice ages we've had - I believe in the nineteenth century the Thames froze thick enough to hold a fair thereon - and the incredibly sweltering weather going on in Europe. But climatic variation is not the point of the argument. It was an example, referring to any change that takes place quickly (from a few seconds to a few hundred years) and requires new survival traits.

Hi defender,You're arguing something of a reductio fallacy here. At no time has a large scale climate change on the order you're using for an example ever occurred that quickly. The "mini ice age" that caused the extreme temperatures in England you refer to actually represented only severe variation of the "normal" climate for those regions effected. For those unaware - there was a short "cold period" from about the 15th to the 19th Centuries. There was another in the 5th Century - the one that allowed the Germanic tribes to invade the dying Roman Empire across the Rhine (the first probably and the second possibly caused by ENSO - "El Nino/Southern Oscillation" - events). However, although both had profound effects on human culture and civilization (wheat failures possibly contributing to the impact of the plague, death-knell of feudalism in England, etc in the former case, and of course the collapse of Rome in the latter), there is no evidence of significant faunal turnover during either period - all of the local critters were already adapted to cooler environments.Only when you deal with climatic effects on the time scale of Milankovitch cycles does evolution have any bearing. If a major environmental disruption occurs over the short time frame you're discussing - say a drought that leads to widespread persistent desertification (what happened in the Sahara, for instance) - then the local/regional populations of all organisms effected are quite likely to simply go extinct. If the species has other populations elsewhere, then the species will persist. If not, bye bye - something on the order of 98% of all species ever existing on the planet are gone. Gradual climate change, OTOH, can allow species to adapt over time.Hope this helps.[edited to fix spelling of Milankovitch. You'd think I'd get it right after all these years...][This message has been edited by Quetzal, 10-20-2003]

How long macroevoution takes depends on what time you are measuring and what you consider macroevolution.However it is quite clear that the changes you mention aren't sufficient - Ice Ages may (and only may!) be sufficiently extreme but are not frequent enough, while the other changes you list are not extreme enough.

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Say any species suddenly is faced with a challenge to survival that will require some new trait to keep it alive. Suppose we have some bears on an island. The climate gets colder. Natural selection kicks in, and soon we have only the bears with genetic information for long hair surviving to pass on their chromosomes. So the gene pool has narrowed down to long hair only.But then temperatures reverse to very hot. However, since natural selection has thinned the gene pool down to longhaired bears, there are no shorthaired bears to breed with to regain genetic information for short hair.

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There would still be variation within all of those long-haired bears. Some of the bears would have shorter long hair, and some would have longer long hair.It all depends upon how quickly the bears can reproduce compared to how quickly the environment changes.

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Obviously, these bears are going to need some macroevolution by random mutation to gain short hair again in order to remain cool.

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Since when did something like "shorter hair" become macroevolution?Anyway, your scenario is not how things happen. Remember, there is still variation within the popularion WRT coat length.Also, there are other ways that the environment might select for individuals in this situation. Bears with the behavioral tendency to move around more at night, or in the deeper woods, or in the water to stay cool would have a reproductive advantage regardless of coat length. Perhaps bears with large ears to radiate heat would be selected for, etc.

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But before the long time periods required by evolution pass, the bears have all perished in the heat.

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That would be an extinction event as predicted.

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Natural selection should have tipped the scales back to shorthaired bears again, only there weren't any after they all died out in the preceding ice age.

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I've explained how this is incorrect.The reason they might die out is not because of a lack of genetic information, but because the changes in environment were too rapid.

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This illustration shows how species diversify, losing genetic information through natural selection,

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This is not at all how species diversify.

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and may become extinct because they don't have time to develop a survival trait. Life on earth is clearly therefore deteriorating.

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I would agree with Rei that we are in a period of accelerated extinctions, mostly due to human encroachment into other species' environments, pollution, etc.However, we still observe, both in the lab and in the field, speciation occuring and new traits evolving in organisms that they didn't have before.Observed Instances of Speciation
http://www.talkorigins.org/faqs/speciation.html[This message has been edited by schrafinator, 10-20-2003]

How would you interpret the acquired ability of flavobacterium to digest nylon. This ability came about due to a frame shift mutation and allowed the bug to take over a niche that was previously devoid of life. This example, IMO, describes an increase in "genetic information" that is counter to the belief in deterioration.[This message has been edited by Loudmouth, 10-20-2003]

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Say any species suddenly is faced with a challenge to survival that will require some new trait to keep it alive. Suppose we have some bears on an island. The climate gets colder. Natural selection kicks in, and soon we have only the bears with genetic information for long hair surviving to pass on their chromosomes. So the gene pool has narrowed down to long hair only. But then temperatures reverse to very hot. However, since natural selection has thinned the gene pool down to longhaired bears, there are no shorthaired bears to breed with to regain genetic information for short hair

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1) I don't understand how you think that "developing longer hair" is even a remotely difficult task, mutation-wise. I wouldn't be surprised if it only took a few BP mutation at one of any of several places in the genome.2) You forget about atavisms. Most genes that dissapear aren't "lost", they just become inactive due to slight mutations, and can reactivate.------------------
"Illuminant light,
illuminate me."

Mutations are not good. Notice the word. It carries a very negative connotation, and there is a reason for that. Science has not proved that any mutation is beneficial to a species, just assumed that there is one, in order to support its theories. Also, the vast majority of mutations are not reproducible, meaning that they inhibit the reproductive system in some way. And some slightly off topic arguments- life does not come from non-life (check out Louis Pasteur's abiogenesis experiments) and the Second Law of Thermodynamics (I have heard this argued in a circle and concluded that backpedaling is a useful way to renege on an argument that you introduced) the lack of fossils is not an argument I use considering that very few creatures of any kind are actually fossilized, since it takes such special conditions. The otehr thing that contradicts Evolution is the existance of self-sacrifice. The ideas of love and humility (in people) and at least defending the young and weak in other animals simply cannot be explained by a natural selection or survival of the fittest, and these traits obviously exist.

You've raised a lot of points here, and while it's sufficient to say you're wrong and poorly informed about all of them, rebutting you is beyond the scope of this thread's topic. If you'd like to discuss these points, you could open new topics: The last is an especially puzzling objection. If you can't see the reproductive benefit of protecting your own offspring, then you're just not very knowledgable about biology. The evolutionary advantage of protecting juveniles should be obvious to the most casual thinker.

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Mutations are not good. Notice the word. It carries a very negative connotation, and there is a reason for that.

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The ability of evolution to occur even though the vast majority of mutations are harmful is demonstrated here. You need to show that *no* mutations are beneficial.

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Science has not proved that any mutation is beneficial to a species, just assumed that there is one, in order to support its theories.

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Ah, so this (as an example) isn't beneficial:Single mutation at the intersubunit interface confers extra efficiency to Cu,Zn superoxide dismutase - PubMedWant more? I'll give you as many as you want - there's an encylopedia's worth of observed examples of beneficial mutations out there.

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And some slightly off topic arguments- life does not come from non-life (check out Louis Pasteur's abiogenesis experiments)

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http://EvC Forum: Evolution has been Disproven

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and the Second Law of Thermodynamics

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http://EvC Forum: Irreducible complexity- the challenges have been rebutted (if not refuted)

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The otehr thing that contradicts Evolution is the existance of self-sacrifice. The ideas of love and humility (in people) and at least defending the young and weak in other animals simply cannot be explained by a natural selection or survival of the fittest, and these traits obviously exist.

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What are you talking about? Your offspring are the ones that carry your genes on - self-sacrifice for them is *utterly necessary* if you want your genes passed on to future generations. In social species, the success of the tribe/troop/flock/pride/whatever is necessary for the individuals in it to pass their genes on; otherwise, all will perish (they share much of the same genetics anyway). If you have a troop of chimpanzees that becomes severely weakened by a lack of unity, there's always another tribe of chimpanzees ready to sieze their territory and kill/injure them in the process.------------------
"Illuminant light,
illuminate me."

Whoops. We're at crosspurposes here. I completely agree with everything balyons said, except that no mutation can be beneficial. Mutations can be beneficial - depending on what criteria you're using - but they can't add information. This ties in nicely with Loudmouth's argument concerning nylon-digesting bacteria. Although that may have looked like new genetic information, or macroevolution, at first, it's more likely to have been a loss of information in that the enzyme catalysis processes became less specific. By a loss of information, the enzymes would be less effective but more general in what they digested, allowing the enzymes to remove any inbuilt inhibition they may have had against chewing up nylon. Proteins and nylon are digested in a very similar manner (which is why nylon is the first substance you'd notice being catalysed if these mutations began). Degeneration again - beneficial for the moment, mind you, depending on whether nylon is good for bacteria, but such losses of information would eventually create an enzyme that is permitted to digest a wide range of substances but is not good at it. Such bacteria would not survive when pitted against bacteria with substrate-specific very efficient enzymes.
But new evidence actually suggests plasmids may be responsible for the nylon digestion. Other bacteria have the same property and could have passed this information to the flavobacteria. See e.g. K. Kato, et al., ‘A plasmid encoding enzymes for nylon oligomer degradation: Nucleotide sequence analysis of pOAD2’, Microbiology (Reading) 141(10):2585—2590, 1995.

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Mutations are not good.

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I, personally, have a genetic mutation which prevented my lower wisdom teeth from forming.I have suffered no ill effects from this lack of teeth.Why should I consider this mutation "not good?"

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Notice the word. It carries a very negative connotation, and there is a reason for that.

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Um, I notice the word. The reason you think it carries a "very negative connotation" is because you don't know whaqt you are talking about. Sorry.

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Science has not proved that any mutation is beneficial to a species, just assumed that there is one, in order to support its theories.

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So, bacteria which couldn't digest nylon in past generations but were observed to mutate and then be able to digest nylon are just an "assumption", not an actual observation?

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Also, the vast majority of mutations are not reproducible, meaning that they inhibit the reproductive system in some way.

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Are you a clone of your parents?I'll let you think about the answer to this in light of what you just said.

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And some slightly off topic arguments- life does not come from non-life (check out Louis Pasteur's abiogenesis experiments)

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...which is irrelevant to if life has evolved.

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and the Second Law of Thermodynamics (I have heard this argued in a circle and concluded that backpedaling is a useful way to renege on an argument that you introduced)

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...which applies only to closed systems, which the Earth is not because our Sun pumps enormous amounts of energy into the system.

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the lack of fossils is not an argument I use considering that very few creatures of any kind are actually fossilized, since it takes such special conditions.

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Wow, you actually got something right!So, what does the fossil record indicate to you regarding the evolution of life on our planet?

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The otehr thing that contradicts Evolution is the existance of self-sacrifice. The ideas of love and humility (in people) and at least defending the young and weak in other animals simply cannot be explained by a natural selection or survival of the fittest, and these traits obviously exist.

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Wrong again!Remember, it's species which evolve, not indioviduals. In social groups, altruism serves the group, which is a survival advantage for the group. If you save your children from death while losing your own, you are saving your genes.

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Whoops. We're at crosspurposes here. I completely agree with everything balyons said,

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that's too bad, because most of what balyons said is very wrong.

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except that no mutation can be beneficial. Mutations can be beneficial - depending on what criteria you're using - but they can't add information.

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Why don't you specify which definition of "information" you are using?

Defender, a reply to message #50 in this tread would be appreciated.You have some pretty major misconceptions about how evolution works which I hope I have explained to you in that message. I'd like to know what you think.

One of my pet peeves ...The second law of thermodynamics applies to all systems. The statement "entropy never decreases" applies only to closed systems, but is not a valid statment of the second law because it's incomplete.