A beginning

You seem to have a good grasp of the opening basics.The only suggestion I would have, and I'll admit it might be a bit nitpicky, is to stay away from the term "fittest."

---

Those who would sacrifice an essential liberty for a temporary security will lose both, and deserve neither. -- Benjamin FranklinWe see monsters where science shows us windmills. -- Phat

I guess part of what I was thinking of was to avoid slipping into the idea that there's some kind of absolute fitness, without taking into account that it must be viewed in terms of fitness for a particular environment. ogon clearly indicated in his summary that he understands that concept, which is why I acknowledged that it's a little nitpicky.

---

Those who would sacrifice an essential liberty for a temporary security will lose both, and deserve neither. -- Benjamin FranklinWe see monsters where science shows us windmills. -- Phat

Imagine a population of small animals with relatively little fur. In that population, there will naturally be some variation in the exact amount of fur that each animal has. If the climate begins to cool, you would expect to find that the average amount of fur on the animals will increase. This is not because the genes in those animals decide that the animals need more fur, it's because, across the population, those animals that have more fur will tend to survive to reproduce better than those with less fur. After many generations, there might be so much more fur that you might not even recognize it as the same animal.As we understand it, genes don't make any effort to produce the traits that organisms need in order to survive. Instead, the organisms that survive are those whose genes happen to produce the traits that tend to make the organisms more likely to successfully compete.You seem to be still quite comfortably astride your bike and learning the terrain.

---

Those who would sacrifice an essential liberty for a temporary security will lose both, and deserve neither. -- Benjamin FranklinWe see monsters where science shows us windmills. -- Phat

ogon, in the sense that the devolpment and evolution of a population of organisms is not directed, it is indeed "by chance." Also, in the sense that mutations occur in genes that take a part in evolution, and these mutations are not directed to any particular goal, it is "by chance." In this manner of speaking, the answer to your question is yes, it is by chance.However, as Dr. A points out, what happens to the population through time, and the manner in which the population tends to change, is not by chance and in some ways, but not all, it is rather predictable.Populations tend to change in response to the selective pressures that are acting on them at any point in time. As in the simple example I contrived earlier in this thread, as the climate gets colder, we expect to see those organisms that are better adapted to the cold thrive. Although this is a very simple example, it serves to illustrate a point. Often those who do not understand evolution focus at the "randomness" of mutations and the "randomness" of how genes combine in each successive generation to try to establish that the whole process is "random" and that evolution happens "by chance." If this misunderstanding of the process were in fact accurate, it would be remarkable indeed if any sort of order arose out of the process. However, there is a kind of sorting mechanism, natural selection, that weeds out less efficient organisms. The selective pressures found in nature tend to push a population of organisms in the direction that will tend to maximize their reproductive potential.Thus, while in one sense it is accurate to say that the creation of new species is "by chance," chance alone is completely insufficient to accomplish what mutation, genetic drift, sexual combination and natural selection accomplish when all operating at the same time.I think we're starting to get a bit more complicated now, but I get the feeling that you do have a good grasp of the basics.

---

Those who would sacrifice an essential liberty for a temporary security will lose both, and deserve neither. -- Benjamin FranklinWe see monsters where science shows us windmills. -- Phat