Classification, another kind of classification, and more classification (Chapter 13)

The technical title of this chapter is "Mutual Affinities of Organic Beings : Morphology : Embryology : Rudimentary Organs."

And that's exactly what it talks about. But first lets begins with the opening sentences of the chapter:

"From the first dawn of life, all organic beings are found to resemble each other in descending degrees, so that they can be classed in groups under groups. This classification is evidently not arbitrary like that grouping of the starts in constellations" (411).

Darwin poetically explains that all organisms of the earth can be classified and there is an order to the system, as opposed to the stars which we simply force into shapes (constellations) so that we can remember them. Then, throughout the chapter Darwin describes the different ways one can classify:

1. Similar/comparative anatomy (morphology)

2. Embryology

3. Rudimentary organs/vestigial structures

He also describes many many ways that we should not classify species. But why go into that if we just have to not do it, anyway?

Interestingly, the traits that many species have are more useful in classifying than the rare ones(418) . This concept seems very backwards to me, but I'll take the word of the scientist.

Another great Darwin moment:

"All the foregoing rules and aids and difficulties in classification are explained, if I do not greatly deceive myself, on the view that the natural system is founded on descent with modification; that the characters...gave been inherited from a common parent" (420) etc., etc. I think "greatly deceive myself" is an understatement. Maybe he should have said, "All the foregoing rules are explained as long as my entire theory is not wrong." But I suppose that language would not have sounded very confident.

There are two interesting metaphors in this chapter (which I, as an un-scientific, literary person picked out, of course). One is the "language metaphor". Darwin supports his idea of a genealogical arrangement of species (races, actually, is his word) by comparing today's races to a modern language: all of the modern languages come from past or extinct languages that slowly changed. Some old languages would have changed a lot and produced many languages, and some may have changed very little. In other words, the process would be viewed in a tree-like graph (as Darwin includes at the end of his book), because the languages change and branch out continuously.

The second metaphor is the "word metaphor". See how they both involve linguistics and not science? That's why I understand them! Darwin compares rudimentary, or useless organs to silent letters in words. They have no use now, but they indicate something about the word's past, about its roots. The same is true for vestigial structures - they may not be useful now, but they were once, and they can be used for classification.

And, of course, leave it to Darwin to shamelessly plug his main theory into all of his explanations (its not like that's the point of the book or anything)! On page 433, he explains why Natural Selection makes sense of classifications of organic beings. I was not going to quote it for you because its long and essentially summarizes most of his theory. But then I figured that sounds like a pretty useful quote to post! He says,

"We have seen that natural selection, which results from the struggle for existence, and which almost inevitably induces extinction and divergence of character in the many descendants from one dominant parent-species, explains that great and universal feature in the affinities of all organic beings, namely, their subordination in group under group" (433).

And, 'lo and behold, he does it again at the end of the chapter. And with this I'll leave you until our FINAL CHAPTER!

"Finally, the several classes of facts which have been considered in this chapter, seem to me to proclaim so plainly that the innumerable species, genera, and families of organic beings, with which this world is peopled, have all descended, each within its own class or group, from common parents, and have all been modified in the course of descent, that I should without hesitation adopt this view, even if it were unsupported by other facts or arguments" (458, bold my own).

Oh, Darwin, I'm so glad you believe your own theory. It's very encouraging.

Tune in for the last chapter!