Darwin’s Principles: Natural Selection

For the record, the two previous posts, this one, and probably a few more are works in progress. I will be jumping around and updating them as I have time to write and as inspiration carries me.  Again, I am discussing this ultimately to discuss the “multiple idea-streams” discussed in the Core Principles post of November 3.

In this post, I will eventually include some text from The Origin, but I know the topic well enough to write some important things immediately.

Background (In BRIEF)

As a bit of background, “Evolution” was not Darwin’s idea. Aristotle proposed a form of evolutionary theory, as did the Q’uran. Erasmus Darwin, Darwin’s grandfather, assumed some evolutionary principles in a poem. Darwin was aware of all of these (perhaps not the Q’uran). Evolution is the hypothesis that organisms did not exist in their present form since their first appearance on Earth. There are a lot of ways that you could interpret this. Some early evolutionists believed that there were a large number of first creations, and that those “types” changed over time. Hence, perhaps God created a primitive form of elephant, and although that elephant does not exist in the world today, and modern elephants did not exist in the world in the past, the primitive elephant changed over time into the modern day elephant.

This is contrary to Darwin’s notion of “common ancestry,” which is distinct but compatible to natural selection. Common ancestry holds that all organisms, from bacteria to mushrooms, oak trees and grasshoppers, cobras and humans, all ultimately had the same ancestor, which was some clump of proteins that could not even be considered a cell by today’s common standards. In fact, it could barely be called living.

Natural Selection is Darwin’s most important contribution. It does not state that organisms change, but how they change. It is a mechanism, describing the well-known and accepted conditions of nature, and then showing how those conditions necessarily leads us to the more radical and controversial natural selection. In itself, natural selection does not prove common ancestry, although it provides a way for common ancestry to exist (Darwin’s Origin is a massive and wide ranging book. After he establishes Natural Selection, he goes through a vast array of other topics to argue that natural selection is not only an existing mechanism, but one with truly wide-ranging implications). I will explain how natural selection works below.

Natural Selection was not the first mechanism, either. Famously, Jean-Baptiste Lamarck had already proposed a mechanism, which was “willing.” An organism is capable of slightly changing its form through the power of will, and those changes are then adopted by the offspring. The paradigmatic example is that of the giraffe. Fossil records show that more primitive giraffes had much shorter necks and legs that modern giraffes. In order to get leaves from tall trees, a primitive, short-necked giraffe would strive to stretch its neck and legs. As a result, the offspring would have slightly longer legs and neck.

Darwin thought this was a silly idea. Plants, for example, do not will. And neither Darwin or Lamarck were animists (the belief that all things have a will).

How Natural Selection Works

The three most important notions of Natural Selection are things that are completely ordinary and non-controversial.

1. Given a number of offspring that were born of the same parents, there will be some variation amongst the traits of those offspring (in simpler terms, you are biologically different from your brothers and sisters).

2. Traits, both physical and instinctual, are passed from parent to child. (You acquire your traits from the traits of your parents).

3. Far more offspring will be born than will survive to maturity and have children (people sometimes forget that this is a very true statement: in our contemporary culture, most children who are born survive to child-bearing age, and it is considered a travesty when they do not. But our contemporary culture presents a relatively new and isolated phenomenon. In nature, and in much of the present, human world, the vast majority of organisms die before they have children).

Following added November 5, 10:35pm CST:

On top of these three simple facts, there is also an very important conceptual shift that needs to be considered. It is close to the third condition, but less mathematical and more severe. In short, Nature is not about chipmunks and song birds playing amongst the calm birch tree and moss. Rather, it is a place of eternal struggle and strife:

“In looking at Nature, it is most necessary to keep the foregoing considerations always in mind–never to forget that every single organic being around us may be said to be striving to the utmost to increase in numbers; that each lives by a struggle at some period of its life; that heavy destruction inevitably falls either on the young or old, during each generation or at recurrent intervals. Lighten any check, mitigate the destruction ever so little, and the number of the species will almost instantaneously increase to any amount. The face of Nature may be compared to a yielding surface, with ten thousand sharp wedges packed close together and driven inwards by incessant blows, sometimes one wedge being struck, and then another with greater force.” (Origin of Species, Chapter III: The Struggle for Life)