Question on how Evolution works to produce new characteristics

Pick one in particular, and we'll discuss it.Bear in mind that the term "living fossil" does not imply prolonged morphological stasis, which is what you actually want to talk about.

However, the fact is that the evidence shows that some types of organism have remained relatively unchanged (at least morphologically) over long periods of time without going extinct. And this means that there must, throughout that period, always have been some environment that was within their tolerance, otherwise they would have gone extinct, wouldn't they?Now that is logic. The fact that stromatolites (for example) have survived for hundreds of millions of years does in fact prove that for hundreds of millions of years there must have been, at any particular time in this interval, some place on Earth in which stromatolites could survive.So yes, I "honestly believe" that it is possible, because the evidence shows that it has actually happened; and things that happen are of course possible.Edited by Dr Adequate, : No reason given.

But if you are going to take that as a definition of living fossil then a lot of things that people call living fossils aren't living fossils, and you should bear this in mind when selecting your example. "The" cockroach? From WP: Edited by Dr Adequate, : No reason given.

And which is that, and how long was the duration?

I don't see the relation that any of that bears to what I actually posted. I explained that.If a species has survived for x million years, then it is necessarily the case that for x million years there has been some environmental niche in which that species could survive. Otherwise it would not have done so.Hence, while the environment of the species may have changed somewhat, it must always have been within the limits of what that species could survive without undergoing (significant, morphological) evolutionary change. Otherwise the species would be extinct.

I don't object to the definition. My point is that in that case you should be cautious about saying that something is a "living fossil", because people call a lot of things "living fossils" which do not fit that definition --- so although you read somewhere that something is a "living fossil", it probably isn't a "living fossil" by Yoshida's definition. No, not at all. My point is that cockroaches have in fact evolved. Proto-cockroaches evolved into cockroaches (and mantises); more modern cockroaches evolved into termites; some cockroaches still look fairly roachy, but they are not identical with Cretaceous species.I know of no cockroach species which would count as a "living fossil", and presumably nor do you or you'd have named one.

Au contraire --- it is evidence, but it isn't an explanation.By analogy, consider the fact that I am still alive at 36. This is compelling evidence that for the last 36 years no-one has ever killed me. It does not explain why no-one has done so. But it is certainly evidence that no-one actually has.In the same way, the fact that a species has not gone extinct is unarguable evidence that since it first arose there has always been some environment somewhere that it could live in. It does not, however, explain why this should have been so.Edited by Dr Adequate, : No reason given.

Yes it is. If you wish to produce a cockroach species as an example of a prolonged morphological stasis, then the question of how long it has stayed the same is very important --- it is important to the question of whether it is an example of prolonged morphological stasis. You're evading even asking the question. You say you want to talk about the roach species which has been stable for longest, but you won't say which one that is. First, there is no such thing as "the" cockroach. You might as well say that "the" mammal has been around for 200 million years.Secondly, as you would know if you'd bothered to read my post, the order Blattaria has not been around for that long. That's when the Blattopterans flourished --- a group which differed morphologically from all modern cockroaches.Edited by Dr Adequate, : No reason given.

This takes special pleading to a whole new level.If you're allowed that sort of excuse, then what constitutes evidence for anything?Is there, for example, any evidence for the existence of giraffes? Of course, we think we can see them, but this could be an illusion planted in our minds by the Babylonian god Marduk using his magic brainwashing ray.But I don't think that this sort of fantasy really deprives evidence of its evidential value. Nor, I think, do you.To quote Hume: Edited by Dr Adequate, : No reason given.

Quite so. And yet you seem to think that the fact that you can imagine it deprives the facts of their evidential value.Well, I'll ask you again --- according to that standard, what is there evidence for? Is there, for example, any evidence for the existence of giraffes? If so, what?