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Ready, Steady, Evolve
Stront writes "New Scientist is reporting that plants and animals can 'bottle up' evolution until they need it. A certain protein 'hides away' mutated genes acting like a genetic valet, however in extreme environments, such as high temperature or noxious chemicals, the cleaning process breaks down and the mutations are released all at once. This goes some way to explaining examples that are considered to defy standard evolutionary theory, such as the Bombardier Beetle."
> This mechanism is so subtle, it is surely proof of an intelligent designer
OTOH, we are so dumb, this is surely a proof that there is no designer.
Furthermore, people are so dumb, that the universe must be a bad dream I'm having, and other people are just an imagination or representations of myself.
I must stop talking to myself.
"Between strong and weak, between rich and poor [...], it is freedom which oppresses and the law which sets free"
Natural selection doesn't work on genes, it works on phenotypes - the expression of those genes. If a bunch of mutations are "hidden" for a time, but then suddenly expressed in a time of "need" (i.e., rapidly changing environment), selection can then do its thing.
This finding in no way goes against natural selection.
and
Develop inhibitor in other tissues so as not to poison self
Did I miss anything? Oh yeah, anyone who thinks postulating God is a smaller step than postulating evolution is fooling themselves big time.
My copy of NS is back at home, so I can't comment on the new stuff, just the old rubbish about 'The bombadier beetle couldn't have evolved' <sigh>
Justin.
You're only jealous cos the little penguins are talking to me.
Well, since you don't want to (can't?) read the article linked to above before criticizing, I'll quote it for you.
Quinones are produced by epidermal cells for tanning the cuticle. This exists commonly in arthropods. [Dettner, 1987]
Some of the quinones don't get used up, but sit on the epidermis, making the arthropod distasteful. (Quinones are used as defensive secretions in a variety of modern arthropods, from beetles to millipedes. [Eisner, 1970])
Small invaginations develop in the epidermis between sclerites (plates of cuticle). By wiggling, the insect can squeeze more quinones onto its surface when they're needed.
The invaginations deepen. Muscles are moved around slightly, allowing them to help expel the quinones from some of them. (Many ants have glands similar to this near the end of their abdomen. [Holldobler & Wilson, 1990, pp. 233-237])
Some invaginations (now reservoirs) become so deep that the others are inconsequential by comparison. Those gradually revert to the original epidermis.
In various insects, different defensive chemicals besides quinones appear. (See Eisner, 1970, for a review.) This helps those insects defend against predators which have evolved resistance to quinones. One of the new defensive chemicals is hydroquinone.
Cells that secrete the hydroquinones develop in multiple layers over part of the reservoir, allowing more hydroquinones to be produced. Channels between cells allow hydroquinones from all layers to reach the reservoir.
The channels become a duct, specialized for transporting the chemicals. The secretory cells withdraw from the reservoir surface, ultimately becoming a separate organ.
This stage -- secretory glands connected by ducts to reservoirs -- exists in many beetles. The particular configuration of glands and reservoirs that bombardier beetles have is common to the other beetles in their suborder. [Forsyth, 1970]
Muscles adapt which close off the reservoir, thus preventing the chemicals from leaking out when they're not needed.
Hydrogen peroxide, which is a common by-product of cellular metabolism, becomes mixed with the hydroquinones. The two react slowly, so a mixture of quinones and hydroquinones gets used for defense.
Cells secreting a small amount of catalases and peroxidases appear along the output passage of the reservoir, outside the valve which closes it off from the outside. These ensure that more quinones appear in the defensive secretions. Catalases exist in almost all cells, and peroxidases are also common in plants, animals, and bacteria, so those chemicals needn't be developed from scratch but merely concentrated in one location.
More catalases and peroxidases are produced, so the discharge is warmer and is expelled faster by the oxygen generated by the reaction.
The walls of that part of the output passage become firmer, allowing them to better withstand the heat and pressure generated by the reaction.
Still more catalases and peroxidases are produced, and the walls toughen and shape into a reaction chamber. Gradually they become the mechanism of today's bombardier beetles.
The tip of the beetle's abdomen becomes somewhat elongated and more flexible, allowing the beetle to aim its discharge in various directions.
Why, that sounds like a series of random... oh, forget it. You'll probably ignore this too.
There's no great mystery; all of the chemicals are common, other beetles exist that excrete them separately; and the temperatures and pressures are not really that great (only just above boiling). So what?
-WolfWithoutAClause
"Gravity is only a theory, not a fact!"I particularly liked "Everything in evolution is supposed to make perfect sense and have a logical purpose" Says who? The whole freaking point of evolution is that it is a choatic process with an ordered outcome. I expect there were lots of little beetles blowing themselves up at some point. Guess what? Those beetles didn't produce any offspring, and thats why you don't see any. The ones that didn't blow themselves up produced offspring. Oh look, more beetles.
The fear of evolution is partly based on the idea that man is perfect, and then from that the fear that a perfect being could have evolved from chaos.
The flaw is believing that man is perfect.
You're confusing two different meanings of the word theory. One meaning is of hypothesis or conjecture, as in a suggested explanation yet to be proven right or wrong.
Another meaning is of governing principles as in "theory of operation". I have a book at home call "Loudspeakers: Theory and Design". The author does not offer hypotheses about how speakers work; he has no doubt as to whether they work and how they work. He's not writing conjecture - he's writing science and engineering - the general body of rules governing the operation of loudspeakers, which the author collectively refers to as their "theory of operation". This second sense of the word can be defied.
In the days of Darwin, the word "theory" in "Theory of Evolution" probably may have refered to the first sense of the word, as a hypothetical explanation of the origin of all species, including ours. But talk to a biologist or naturalist today and he'll tell you they have no doubt but that evolution is a fact; how it works, its principles of operation, is something they're still exploring and trying to explain.
This confusion between the meanings is something the Bible-thumbers love to exploit (I'm not lumping you in with them, though). They jump up and down and shout about how evolution is just a "theory" and that their half-baked Creation Science theories deserve equal consideration in the schools. Don't buy it. Evolution is a fact. We're sure of the big picture; it's just some of the details that we haven't worked out yet.
--Jim
however in extreme environments, such as day before the deadline, the manager process breaks down and all the kludges are released all at once.
And it's been a theory for a good twenty years at least in evolutionary biology. It explains why we find a lot of fossils of different species, but very few fossils that qualify as a "missing link" between species. This just gives a reasonable explanation for the mechanism which produces punctuated equilibrium.
Do not confuse duty with what other people expect of you; they are utterly different.Duty is a debt you owe to yourself.
Let me preface this by saying that I do believe in God (after thinking everything through and deciding for myself)
:) ). This was all because I felt a bond to my common man, not because I feared reprisal in the afterlife. How were my morals any less real than the morals of those who 'do right' because their God tells them to? Belief in God in no way equates or even implies morality or ethics. Look at the Sept. 11th hijackers. They most likely believed very strongly in God. You could argue that they didn't follow God's teachings, but the point is that they believed they were.
Just because evolution was taught as truth in high school and college, and it allows you to live your life any way that you want without concern for life after death or accountability to a higher power doesn't mean that you should buy it.
It upsets me that so many people who believe in God imply that simply because someone does not believe in God they cannot have any true morals or ethics. I did not believe in God through most of high school and college, yet (I believe) I was a very moral person. I did not drink, did not do drugs, worked hard, tried not to lie (though I was somewhat less successful in that regard
I realize that this is going to get modded down, but it frustrates me that so many people who pull this "I'm an intellectual therefore I believe in evolution not God" crap are actually simple drones of the left. Think for yourself, will ya?
(Note, I have moderator access, but I think responding is much better to this than modding down)
I am sure there are just as many drones on the right who simply believe in God because it is easier. Most Christians (the majority of religious people in America) have not read the Torah, Koran or Bhagavad Gita. Why is this? Is it because they know after reading the Bible that nothing else can possibly be correct? They may say that to themselves, but I doubt it is the truth. I find it much more likely that the Bible is what they were brought up with, and it is simply easier to follow what they already know as opposed to working to figure out what they can truly put their faith in.
I find it perplexing that many people take the time to diligently study the religion they were brought up to know, yet few take even scant moments to study the countless other religions in this world. Well, no, it doesn't really perplex me. It saddens me.
--David
I'm doing the traditional /. thing and not actually reading the article, but I assume it's the old news on heat-shock and chaperone proteins being shown to be a general case.
This isn't "saving up" mutations. This is a system for supressing aberrant mutations breaking down in stressful environments. The True Believers out there would like to phrase this to illustrate the cleverness of natural selection, but this is the failure of a beneficial system leading to a honking buttload of mutants appearing. Nothing more. Yes, throwing a bunch of random solutions at the problem may find an answer and allow a population to continue living in a stressful environment, but it's a bit assuming to try to say the system has evolved to break down in this manner (though it is a rather elegant failure mode).
As for the bombardier beetle...
Hydroquinone and hydrogen peroxide, when mixed, turn brown over the course of a couple minutes and won't taste very good. Various beetles besides the Bombardier Beetle use the chemicals, uncatalyzed, merely for the foul taste. Evolution can work in as many steps as it likes increasing the foulness of the taste without any delightful imagery of exploding beetles occurring to anyone.
Of course the page linked to is slow to abandon such delightful imagery so, while it is kind enough to mention that nothing very exciting happens unless you add a catalyst, it likes to give the impression that without that catalyst (or "anti-inhibitor", if you please) the beetles would die a horrible death in the manner of a piece of popcorn, though not quite as tasty.
Let me let you in on another "secret". There can be huge ranges of activity in classes of closely related proteins. This is especially true of the enzymes responsible for catalyzing naturally occuring reactions between simple chemicals. This is a bit of a problem for the Creationist because their idea of the beetles stumbling across a highly efficient enzyme and blowing themselves to bits for generations is very useful. Having them stumble across a weak version that merely made them taste a little worse than their competitors when an attacker mixed the chemicals together is hardly an exciting idea. Nor is it exciting for this weak enzyme to follow the same path of increasing the foulness of the taste that the parahydroxybenzene glands went through.
Of course, once this enzyme reaches a certain level it does get to be dangerous to the beetles. Chance encounters with learning predators that may have only have caused injury become fatal due to the beetles' own defense mechanism (though, because the added foulness of taste deters predation, this is still beneficial to the species, though not to the individual). Any solution is beneficial, as the alternative is death. The apparent winner is to excrete the chemicals, which isn't surprising as some of the other Brachinus species do this without the fun of superheating. Coevolution of improvements to the catalyst and to the ejection system gives us what we have today.
Unfortunately, answering one set of Creationists' call to provide an explanation is met with catcalls of "just-so-story!" from another set. It's really best to ignore them as a group... which, hey, is what I'll be doing.
Simple Machines in Higher Dimensions
Every so often, a biological/evolutionary/ecological topic comes up on Slashdot. Now, folks here are mostly engineers of one sort or another, not biologists, and it shows.
:-) As someone who has way more than dabbled in both fields, I can say that a hard engineering mindset does not lend itself to understanding the biological sciences in general, and ecology/evolution in particular.
I have an MS in ecology and population genetics, but have also made my living in the CS field for years (to pay the mortgage, you understand
Evolution (and I've taught college courses on the subject) is not engineering. To understand it, you need to understand ecology, genetics, biochemistry, lots of general biology, etc., etc. There are few topics with more misunderstandings, by people who think they understand it all, and don't. Including some people in the field, har har.
Finally, regarding the Creationists and the "irreducible complexity" thing. As the Theory of Evolution got traction in the intellectual world, the Creationists always pointed out something we didn't understand as proof of a Creator. As more and more became understood, they retreated to the next thing. This was called the "God of the gaps" approach - if we don't understand NOW what's going on, it must be GOD!
That's how I feel about "irreducible complexity". It will be found to be reducible. Well, maybe, mabye not. Where is it written that talking monkeys should necessarily come to understand the Cosmos in all its glory? That's what we are, boys and girls. For all our wonderful accumulated knowledge, there's an infinite ocean of subtlety out there... there's no guarantee that it's all accessible to our brand of cognition or any other computation either.
We return you now to your regularly scheduled trollfest...