Evolution is change in the gene pool from generation to generation.

Thanks for the answers so far

However I fear that some lose end are still somewhere here.

Evolution has indeed to do with genetics, there is, what I shall call "natural variation" (like brown, black, red or blonde hair) and there is mutations wich sometimes do and sometimes don't have an effect on the survival of an organism or species.

I've seen examples of all sorts of mutations and there are many types of mutations wich all have a different potentiallity for change. As there are various ways in wich they can be caused and (afterwards)selected.

I have seen many examples of mutations and variations and tests and all that and every bit I read or see proves another small or big part of the puzzle, but I sometimes appear to lose the big picture when focussing on the details.

You know what I mean?

The etymological roots of evolution come from evolvres, in Latin, meaning "to roll out". Today, it simply means change. Presumably, you are referring to biological evolution, also called organic evolution. Evolution in this sense refers to the change in frequency of genes down a lineage. Evolution is not concerned with ontogeny, the development of an individual organism. Organisms do not evolve by themselves. What is occuring is descent with modification, where the variations in any population have selective pressure against them, pressure which is dictated by the environment, which results in the alteration of gene frequencies through a lineage. In this regard, evolution is determinstic, in that the process is not guided by luck or chance.

Again, thanks for the answers and the link.

 This is a quote from ToO:

" "In the broadest sense, evolution is merely change, and so is all-pervasive; galaxies, languages, and political systems all evolve. Biological evolution ... is change in the properties of populations of organisms that transcend the lifetime of a single individual. The ontogeny of an individual is not considered evolution; individual organisms do not evolve. The changes in populations that are considered evolutionary are those that are inheritable via the genetic material from one generation to the next. Biological evolution may be slight or substantial; it embraces everything from slight changes in the proportion of different alleles within a population (such as those determining blood types) to the successive alterations that led from the earliest protoorganism to snails, bees, giraffes, and dandelions."

- Douglas J. Futuyma in Evolutionary Biology, Sinauer Associates 1986

It is important to note that biological evolution refers to populations and not to individuals and that the changes must be passed on to the next generation. In practice this means that,

Evolution is a process that results in heritable changes in a population spread over many generations. "

I think that the start, where political system evolution and biological evolution were seperated was one importaint one.

Using the word "evolution" when talking about political systems was indeed confusing, since political systems evolve under guidence and evaluation of (more or less) intelligent people, wich of cource, is not the same as random change.

There are, however, a few questions if you don't mind, for deludegod interpreds evolution to be (almost) determenistic and NOT the result of chance and luck (but probably excludes intelligent guidence also). Yet Yellow points out that there is no change in phenotype required.

The two of you may not be directly contradicting, but I do feel a little tention here, since if it is deterministic (the enviroment forces a species to evolve), how can an enviroment force (not cause, but really force) a genetic mutation if the result is that there is no change in the phenotype?

A semi-related question is, that following this line of thought, it may be suggested that the frequency and/or intensity (and maybe even the efficentcy) of mutations rises when a species is endangered?

It's clear to me that a species wich is challenged will SHOW more (beneficial) mutations, but it's hard to see more mutations being caused, but maybe this is just my poor understanding again

Well, sometimes I don't know if I know what I don't understand

 This sure helps, in the sence that this is what I read a lot.

But like I said in the first post: after this I get lost in the details, for than I start looking at wich (micro-biological) processes are involved in mutations and what do they actually do on the small scale.

The most commen seems to be the so-called "point-mutation" wich is basically nothing else, other than erasing, adding or changing a single gene (or allel) in a DNA-string.

Like a computerprogramm with 1's and 0's and than changing that 1 by one.

Often it's easy to see how what change was made and how it affected the phenotype (or not). But when I start working on the results of such point-mutations I see that most have no effect; no change what soever on the phenotype. Well, how than can natural selection take place?

Most of the other effects are harmfull and natural selection works against this mutation.

In very few cases this point mutation not only has an effect on the phenotype AND is beneficial. However, in most (if not all) cases the result on the phenotype may be beneficial, but on the microscale it may be that a (no longer usefull, or even stand-in-the-way) gene is made inoperable.

So is it my lack of immagination, am I completeley wrong informed or do other types of mutation occur wich do have the potential of increasing the amount of functional genes, or changes gene A in such a way that it can execute an other (new) function without losing it's previous function before the new function is operative (since if you "lose track" of a gene half-way, than natural selection will not be able to select).

I hope you understand what I'm asking for, I didn't really use scientific language here, but I've got the creepy feeling that when this is solved, the whole evolution-picture will be clearly visable in my mind

Again I'll begin with a thanks, the essay looks very informative and I'll be the first to check on it when I want to know something more about sex and genetics.

However the problem isn't in the fact that harmfull mutations happen, but in the nature of the usefull mutations themselves.

I think you are right pointing out that I mentally put mutations in a box as if in it exists in a vacuum, but that has two reasons.

First of all I'm sort of a control freak I wan't to be there every step on the way.

Secondly because I think that for some reason it does happen in a vacuum.

Let me explain what I mean: the genes mutate and often have some sort of effect on the phenotype (I'm talking explicitly about mutations, not about variation, for you first need something to make variations with). This is a one-directional road, going from genes to phenotype.

Turning the other way is impossible for multi-celled organisms (there is, as far as I know, some promesing research going on with bacteria, but that mechanism wouldn't work on other forms of life).

Conclusion, genes will have to "mutate themselves" and the only way I can see that happening is in a vacuum.

Yes, natural selection occurs, but only AFTER there has been a mutation. You can't select something that isn't there.

It's like looking at a monitor: I can see red, green and blue bars, very very small. Than all the sudden I look back and I see what the hack I'm doing.

The missing information is of cource how light works and how my eyes interprid the incoming light.

It's the same for me still I fear: I see the small mutations and I hear scientists who say that this leads to (is) evolution, but I can't connect the dots somehow. :S

Well, I am reading "unweaving the rainbow" at the moment... Though I'll probably have no choice but to read eighter of those books you mentioned, I do prefer books wich are written for scientists.

On an other post I read the following analogy, it's about taking one step forward each time and in the end climbing mnt. Everest.

However, given the nature of the beneficial mutations, I sometimes wonder if it's going in the right direction, given that so many, if not all, of the point-mutations destroy a no-longer usefull gene.

like the first mammels wouldn't have had white hair, yet the polar bear does have white hair. Just one small example I can think of right now, but that means that on the genetic level it lost the pigment-generating gene(s).

Beneficial? Halleluja! But also a loss. I've read several other examples also...

Oke, so "the" answer is time? Like give it a few million years and it ought to have happened?

That sounds a bit more reasonable, but can you show me (a book/website with) some calculations? That would really help