Clades and Kinds

Everything you just said is completely true, but your understanding of it is completely false.A clade is any group of organisms such that no organism outside that group is more closely related to an organism inside that group than the members of the group are related to each other. For example, humans are a clade. Humans, chimps, and bonobos are a clade. Primates are a clade. Mammals are a clade. Tetrapods are a clade. Vertebrates are a clade. Animals are a clade. Life is a clade.From this definition it is evident that no evolutionary event can take place which shifts a lineage from one clade to another. Every lineage must, by definition of "clade", always remain in every clade that it's in. So, for example, evolution did not stop humans from being primates, or from being mammals, or from being tetrapods. And so long as you're still a vertebrate, the fact that you're descended from fish needn't trouble you.

But if they did, they'd still be the same "kind", right? Even though you have not explained how to quantify "information" one can easily prove that it is possible to gain information through mutation for any definition of the word "information" such that:* Two identical pieces of DNA contain the same amount of information.* The "null string" consisting of no DNA contains no information.* Some strings of DNA contain information.This is trivial. The fact that it is not obvious to creationists I attribute to their habit of not listening to what they're saying.

I am indeed familiar with the ludicrous posturing antics of that particular worthless charlatan. I have debunked his arrant hogwash here.Don't tell me you've fallen for that nonsense. That's just sad.

Well, yes and no. Clade is defined by lineage. But it turns out to be a powerful concept about the rest of biology. That's why it's such a good idea.Your comment is as though you said: "This is kinda odd, it seems as though the periodic table focuses only on proton number and not really chemical properties".Now, in a sense this is a true thing to say about the periodic table. But it rather misses the point. Because it so happens that we live in a universe where proton number is the key to chemistry. Sure, we can imagine a universe where this was not the case, and then ordering elements according to their proton number would be lame and silly. But as it happens we do not live in that universe. We live in one where the proton number is the crucial piece of information about an atom.In the same way, we can imagine a universe in which birds were descended from cows as well as from archosaurs. And if that was the case, then the concept of a clade might not be much use to biologists. But it so happens that we live in a universe where the concept is useful. It so happens that arranging species in clades does indeed provide us with insights into the biology of the species. And this is why it's a good idea.Edited by Dr Adequate, : No reason given.

That's one of those wrong-end-of-the-stick questions.It depends on whether you mean "cladistics" as a set of methods or as a body of results.