I am going to use the discussion points found on RichardDawkins.net as the basis of this feature.

Calilasseia is the author of the post and deserves many rich accolades for assembling so much useful information in one spot. This constitutes an open thread of sorts, please leave your opinions and observations in the comment section.


[24] Inheritance basics (and the canards destroyed thereby).

Getting back on topic with respect to evolution, there is a basic concept that needs to be deal with here, and which at a stroke deals with several creationist canards, such as the farcical “I’ve never seen a cat give birth to a dog” nonsense, which, if it ever happened without laboratory intervention involving IVF and implantation, would constitute a refutation of evolutionary theory.

That concept is, quite simply, inheritance. Inheritance is a process, that even the mythology creationists claim to adhere to, accepts as valid. Though given the hard evidence from approximately four thousand years of agriculture prior to said mythology being written, not to mention the evidence of inheritance in humans that must have been visible even to pre-scientific man, said mythology would look even more ridiculous if it tried to deny the validity of inheritance. Well, guess what? Here’s the simple point that every creationist fails to understand, and which lies at the root of many of the canards they give credence to, and to reinforce this point, I’ll make it stand out:

Evolution is based upon inheritance.

That’s right. Now this is so simple a notion, that many of the people writing about evolution have failed to reinforce this achingly simple fact, presumably on the basis that they assume that their readers understand this. The problem is, of course, that creationists manifestly don’t understand this. If they did, they wouldn’t erect some of the half-baked nonsense that they do. Where evolutionary theory differs from other ideas about the biosphere, is that it postulates that inheritance unifies the biosphere. Evolutionary theory postulates that ultimately, we and all the other living organisms on the planet are linked by inheritance. Which, as a corollary, leads to numerous testable ideas, ideas that have been tested, and which, as a result of passing those tests, have in turn given rise to a whole new scientific discipline called molecular phylogeny. This isn’t magic, because inheritance isn’t magic. Inheritance is a process that is so simple, it was amenable to systematic analysis by a monk. Which once again, demonstrates the utility value of paying attention to reality, and learning from empirical test, as Mendel did.

Now, since evolutionary theory postulates that inheritance is a key process in the development of the biosphere, this should deal at a stroke with the fatuous “I’ve never seen a cat give birth to a dog” drivel that creationists erect, because there is no way that a cat could pass on an entire, complete set of genes from an entirely different lineage to its offspring. An organism can only pass on whatever genes it dispenses in its gametes, and most of those it will have obtained from its parents, the odd mutation here or there contributing a small additional amount of variation. However, thanks to meiosis, which I briefly mentioned in [14] above, offspring are not exact copies of their parents (which would be hard to achieve anyway with a 50/50 split of genes inherited from each). Meiosis involves some interesting gene shuffling, so that different gametes contains different mixtures of the parental genetic material (for which, again, that nice Mendel fellow provided evidence in those pea plant crossing experiments). As a result, variation will be disseminated across generations. It is this variation that evolution works with. To reinforce this point, inheritance is a dynamic process across generations, and it is the outcome of that dynamic process that provides the raw material for evolutionary mechanisms to work upon.

Oh, and a video bonus!