30 November 2011

Notes on Darwin's On the Origin of Species

Having completed the second chapter to On the Origin of Species (OOS), I have to admit, it is getting easier to understand. I've been jotting down what I feel to be key parts, along with paraphrasing certain ideas in order to follow with my own mind, what Darwin arrived upon. I've also noticed that my knowledge of basic biology is embarrassingly framed in cobwebs and matted by dust, stranded in the same position I originally left it during my high school freshman year.

In order to refresh my memory, I paid a quick visit to wikipedia's entry for Genus (or Genera). It was there that I found a very useful diagram for the hierarchy of biological organization. Darwin, speaks mostly on variation and variety in regards to species and genera in this chapter, aptly is it titled Variation Under Nature.

Of the ideas introduced in this chapter the very first that reached a hand out to me was that of range and dominance of a species and variety over a country or land.

...for, as varieties, in order to become in any degree permanent, necessarily have to struggle with the other inhabitants of the country, the species which are already dominant will be the most likely to yield offspring, which, though in some slight degree modified, still inherit those advantages that enabled their parents to become dominant over their compatriots.

The success of the species and genera can be said to lie in its varieties, according to Darwin, species of larger genera usually produce larger varieties within the species itself. Over an area as massive and varied as a country, a species found throughout this area will encounter variations in nature that select or favor certain complementary variations of the species. Darwin states that species are in essence, varieties of other species that have become distinct enough to permanently become separate from parent-species. And species are continually being manufactured through variations, so evolution is a phenomena without a goal, acting through variations on species, sometimes those variations are significant enough that they give birth to a whole new species.

With enough species contributing to an increase on genus, will a variety exist on genus and later family, order, class, etc.? Life had to begin as a species, or several varieties that eventually became a species.

And it may be said, that in larger genera, in which a number of varieties or incipient species greater than the average are now manufacturing, many of the species already manufactured still to a certain extent resemble varieties, for they differ from each other by a less than usual amount of difference.

We have, also, seen that it is the most flourishing or dominant species of the larger genera which on an average vary most; and varieties, as we shall hereafter see, tend to become converted into new and distinct species. The larger genera thus tend to become larger; and throughout nature the forms of life which are now dominant tend to become still more dominant by leaving many modified and dominant descendants. But by steps hereafter to be explained, the larger genera also tend to break up into smaller genera. And thus, the forms of life throughout the universe become divided into groups subordinate to groups.

The more I read Darwin's words and try to rephrase them, though understanding them better than before--I find that his wording was sufficient and pretty comprehensible when you realize that in these chapters, evolution is acting on variations. Variation on species of bacteria, plants, insect, and animal kingdoms alike. My confusion arose and still arises from the mistake of thinking in terms of only animals or creatures. And though, any species of life is just as good as any other for an example of evolution, I'm finding that once I exclude examples altogether, I'm better at understanding the specific principles at work in general life.

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