I hope this is not a stupid question because many people say that me being YEC fundamentalist Christian is actually not very bright. So perhaps somebody can help me out:
Does evolution happen by chance ?
You need to be considerably more specific about what exactly you mean with “by chance.” If you mean, for example, that somewhere a lizard suddenly grows a beak, some feathers and a pair of wings, and thus “by chance” turns into a bird, then that is a creationist straw man, and a very silly one at that. In fact, if such a thing were to be observed, it would refute evolution.
Strictly speaking, evolution is the study of gene and allele frequencies. This means that evolution concerns itself with how certain genes (or alleles) become abundant or scarce, and the factors that play a role.
Evolution has two main drivers. First, there is “a source of diverse raw genetic material” carried by the totality of organisms belonging to a particular species. Second, there is the collection of environmental factors that determine which of those organisms are more suited to their living conditions and are better able to produce offspring. The better-adapted ones will survive and procreate preferentially, and so their genes will become (relatively) more abundant, while the less successful ones will tend to become scarcer.
It should be noted that the process is statistical, not strictly deterministic: any one poorly adapted specimen could outlive and outbreed any one well-adapted one but, overall, the well-adapted ones will outlive and outbreed the less well-adapted ones. This part of evolution is what is called “natural selection.”
The “raw genetic material” mentioned earlier varies among all the individual organisms of a species. This variation has an element of chance (or randomness) to it insofar as specific genetic differences between individuals are for all intents and purposes unpredictable. The genetic makeup of a specific organism is largely determined by that of its progenitors (parental line) but not entirely. Copy errors and mutations are chance occurrences that keep feeding (and possibly extending) the range of genetic diversity, which the environment then filters for suitability.
Many such variations are largely neutral in terms of their effect on survivability. By pure chance, some genes will be more and some less abundant from generation to generation, just as you are unlikely to find exactly the same number of heads and tails in a long series of tosses of a fair coin. This accounts for so-called “genetic drift” where the genome of a population changes over time. However, sometimes a sudden change in the environment (which, again, for all practical purposes is a random event) can make one of these variants more successful than the others and so ensure its proliferation.
Therefore, the answer to the question is that, while evolution has some elements of chance to it, it does not produce haphazard results basically because less suitable variations are soon eliminated.
'Luthon64
To that excellent answer, I can only add this link: http://en.wikipedia.org/wiki/Weasel_program 
And maybe another short summary: Variation in genes is random, natural selection is not.
Depends what you define as “evolution”. I understand it to mean the transmutation of species.
There is no need to add to Luthon’s excellent description 
However, I would like to point out a discrepency between the title of this post and the description. The most simple answer to the question: “Does evolution happen by chance” is no, but it does not follow that it is “directed” either. There is no dichotomy there, not even a false one.
I agree with bluegray V, good answer 'Luthon64. I would like to suggest an alternative answer - No. 
This is what Richard Dawkins said in an interview -
Again it depends what concept you as signal sender is sending to me signal receiver using the symbol string ‘evolution’ - what protocol are you using.
Since the question is yours, what do you mean by evolution?
Using the simple definition you offered above, the answer is still “no”. Additionally, I can’t think of any variation or nuance of the definition of evolution in Biology that would change my contention that “by chance” and “directed” do not establish a dichotomy.
The definition of “directed” possibly could, but that is a seperate issue and would depend on why someone takes issue with it (I only picked up on it when I re-read my post, but I suspect Luthon would have called me on it if she were online) ;D.
Have you actually read my reply? It includes a definition of what evolution is. And the phrase “transmutation of species” is a dead giveaway. Speciation is, considered from the gene/allele frequency perspective, actually incidental, a mere by-product of the influence of the environment on genetic interactions. It is why Richard Dawkins wrote of The Selfish Gene.
You’re dodging the issue here, especially considering that you have given your understanding of evolution in the post immediately before the one cited above.
You’ve been here before using a slightly different name, haven’t you? And before? And before?
'Luthon64
Wikipedia:
In biology, evolution is change in the genetic material of a population of organisms from one generation to the next. Though the changes produced in any one generation are small, differences accumulate with each subsequent generation and can, over time, cause substantial changes in the organisms.
== rephrase ==
The concept that Gould had in 2002 with the word evolution is change in the genes of an organisms.
But Darwin didn’t know about genes, who is Gould interpreting, the wikipedia nr.1 reference doesn’t tell us. Who is this person that decided that “genes” must be associated with the word evolution ? Because theories are always formally defined.
The concept Darwin had with “evolution” was the unrolling of pre-fabricated beings by God , this is how a reader read OoS in 1859. Is this the same concept Gould had in 2002 and what is the relation to Genes, how did Darwin solve a problem he couldn’t define.
I am the old mentari but lost my user name and password.
And what of it? Isaac Newton didn’t know about spacetime manifolds or complex numbers or photons or quantum electrodynamics either. That hardly invalidates his observations on statics, dynamics, optics or gravity. And nor did Darwin’s ignorance of genetics invalidate his observations re descent with modification.
Why, he’s giving you a synopsis of things put forward by the people who put together the “modern evolutionary synthesis.”
That would be Julian Huxley, R. A. Fisher, Theodosius Dobzhansky, J.B.S. Haldane, Sewall Wright, E.B. Ford, Ernst Mayr, Bernhard Rensch, Sergei Chetverikov, George Gaylord Simpson, and G. Ledyard Stebbins among others, i.e. the people who put together the “modern evolutionary synthesis.”
Do you have any evidence in support of this rather remarkable contention? Any at all? Because your idea that Darwin’s concept had any “god” in it is, as far as I can tell, pure fabrication. Not only that. It also seems that none of your previous discussions here have disabused you of the ridiculous notion concerning “the unrolling of pre-fabricated beings” by your god (or anyone else, for that matter). But even if Darwin (or any 19th century reader of his work) had inserted a god into evolution, we have learned a few things since then, including about the superfluity of a god in evolution. Perhaps you’d care to join the rest of us here in the 21st century right after you first find out how science advances and how knowledge accumulates.
Ignoring the fallacious take on what Darwin (or a 19th century person) had in mind with evolution, the answer is still a resounding, “No!”
For the first part, read the link I provided earlier. Then you will realise that Darwin left unsolved the problem of heredity and the mechanisms by which it proceeds.
'Luthon64
I’m in no way as knowlegable on this topic as some of the other members of the forum, but I would like to add something that may shine some light on your post, mentari.
What you are referring to is the scientific method, also discused here.
The wonderful thing about this, as I see it, is that it allows advancement. Theories are also constantly tested. In other words, if research provides additional information, this will be incorporated in the theory, thereby expanding what we understand about the theory and perhaps even to fine-tune the definition.
It is almost unfathomable to think that modern research into genetics can once again prove a 150 year old theory like Evolution. The scientific method has proven itself once again.
So what if the definition of the theory “evolved” as well? It still does not change the original concept, as outlined by Darwin?
In any event, I would not define Evolution as per your quote from Wikipedia. That can perhaps be classified as a description of the theory. I would, in layman’s terms, define Evolution as the History of life. Scientists act as investigators, to determine this history.
In the past, they had fossil records to go by, but as science progressed, they found genetics as additional resource for their investigation. Darwin would have given anything to have had this to his disposal.
Sentinel
PS. Luthon posted something while I was typing, but I'll post this anyway
The only comment I can make in addition to Luthon’s post (that makes mine look as if it was done by a 3yr-old 
) is on the following:
I agree with everything that was said.
The only example that I know of, where Darwin, being a Christian at the time of his initial voyage, considered God in any of his research, can be found in the book, Saving Darwin - How to be a Christian and believe in Evolution.
I mentioned the following, in a recent post:
This does not mean that God forms part of Darwin’s Theory. It merely suggests that, being a Christian, he would have had some thoughts on the subject.
To avoid confusion, please use the links provided to get new login details. If you have any problems with that PM or email me and I’ll sort it out.
Strictly speaking, evolution is the study of gene and allele frequencies. This means that evolution concerns itself with how certain genes (or alleles) become abundant or scarce, and the factors that play a role.
Luthon, I don’t particularly like this definition because it confuses the process of evolution with the study of evolution (i.e. Biology).
Does evolution happen by chance?
What chance is will vary depending on your point of view.
If you are an objective observer of evolution, mutation will be random (non-directional, accidental) and natural selection will be a directional influence.
If you are a theistic observer of evolution, then I suspect neither mutation nor selection will happen by chance.
If you are an evolving species, both mutation and selection will be random.
If you are a collection of cellular organelles and molecules, mutation will be predetermined and unavoidable, and selection random.
Actually, I don’t think the idea of CHANCE makes much sense at all.
Mintaka
It was Halloy’s term from his paper in 1848. Halloy was a Catholic theist who believed in God. See http://groups.google.com/group/alt.talk.creationism/browse_thread/thread/d138b2c03c35d64f. Your concept with Descent with modification isn’t the same as Halloy: Why are you then using his term? - what is your concept.
In a recent essay in COMMENTARY, “Has Darwin Met His Match?” (December 2002), I discussed, evaluated, and criticized theories of intelligent design, which have presented the latest challenge to Darwin’s theory of evolution. In the course of the discussion I observed that the evolution of the mammalian eye has always seemed difficult to imagine. It is an issue that Darwin himself raised, and although he settled the matter to his own satisfaction, biologists have long wished for a direct demonstration that something like a functional eye could be formed in reasonable periods of time by means of the Darwinian principles of random variation and natural selection.
“…Darwinian principles of random variation and natural selection…”
Note how “random and directed” ,“random + non-random” or “motive + non-motive” is brought in with this sentence. Selection is the protocol string we use to transmit from signal sender to signal receiver the concept of directed, motive, intent and consciousness. “Selection” is not some sort of abstract entity it is a word - semantics, below pragmatics. Like a king is above his subjects pragmatics is above semantics.
The concept that anything is the result of either random or directed,motive,non-random has got nothing to do with “Darwinian principles”. It is a disguised truism reformulated in bogus undefined “Darwinian” terminology. It is sad that Berlinski and YEC,ID and EVO fails to notice the truistic nature of the sentence. We are dealing with an underlying myth of sea monsters being slain by Gods, followed by circular reasoning (nobody knows whether Tiktaalik had offspring), Truism - Wikipedia and Tautology Wiki | Fandom sealed with a web of incorrect grammar such as Dawkins “… if you add in selection…”. The word “selectus” can’t be added to anything like you would add sugar to coffee, in the same way that John can’t crank wooden cheese: it makes no sense.
Not really. The process of evolution is the resultant (or the emergent, if you wish) of variations in gene frequencies over successive generations, as determined by all of the factors affecting them. In this way, the definition cuts straight to the heart of the matter, both in terms of what evolution is and what needs to be studied in order to understand it.
Note also that “random” in the context of evolution is not to be taken as meaning “arbitrary” or “indiscriminate” or “chaotic.” As indicated in an earlier post, “random” in this context must be taken to mean that evolution is not goal-directed except perhaps in the same trivial way that a freefalling object can be said to be goal-directed, i.e. as governed by natural laws. This is actually what these discussions with religious nuts are all about: they reject the idea that their existence is effectively an accident because they can’t live without the reassurance that they were meant to be. When you scrape the surface a little, it soon becomes clear that it’s an ego thing, really.
Okay, so once again you’ve taken to your favourite tactic of flogging that tired old semantic goalpost-shifting hobbyhorse of yours, all the while bouncing around in a decidedly unproductive game of intellectual hopscotch. It is no doubt derived from the very wellspring Werner Gitt tapped for his farcical informatics absurdities.
Just like your above reply, then. Given the fact that evidently you never actually pay attention to what others tell you, that you never address the counterpoints made to your claims with anything besides the usual incoherent, inconsequent, irrelevant and frequently incomprehensible drivel, and that you post the same nonsense all over the Internet again and again, I’ll no longer engage with you. If you wish a rational discussion with me then I suggest that you abide by the usual rules for such. Those rules would include a modicum of respect for sticking to the topic and also, if nothing else, at least acknowledging counterpoints.
'Luthon64
Those rules would include a modicum of respect for sticking to the topic and also, if nothing else, at least acknowledging counterpoints
Amen to that!
As an example of how rational and polite discussion should play out, I have queried Luthon’s definition of evolution as a field of study in my previous post. She has not just skipped over my query in the hope that it will go away, but immediately offered a rational clarification. While I sort of :-\ see the point, I still think her definition will lead to unnecessary confusion. But I have at least been exposed to a fresh outlook on a topic I thought I knew quite well, and will give it some thought. This is the point of debate. Everyone is a winner if we can put ego aside.
Mintaka
Where was this formally established ?
Who says so ?
John S. Wilkins from scienceblogs.com says there is no such thing as a natural law. Nobody knows if gravity will be 10m/s.s 5mins from now, we are assuming it will be. Assumptions aren’t laws, laws are absolute certainties.
Quote from: Anacoluthon64 on Yesterday at 23:46:45 The process of evolution is the resultant (or the emergent, if you wish) of variations in gene frequencies over successive generationsWhere was this formally established ?
Molecular biology teaches us that genotype determines phenotype. So gradual phenotypic changes in subsequent generations must have its basis in genetic variation.
Quote from: Anacoluthon64 on Yesterday at 23:46:45 Note also that “random” in the context of evolution is not to be taken as meaning “arbitrary” or “indiscriminate” or “chaotic.”Who says so ?
You just did:
Like a king is above his subjects pragmatics is above semantics.
John S. Wilkins from scienceblogs.com says there is no such thing as a natural law.
Thats good to know. I will keep that in mind next time I walk through a wall.
Mintaka