Natural selection/Talk

HomePage | Recent changes | View source | Discuss this page | Page history | Log in |

Printable version | Privacy policy

What does this mean:

the best explanation of speciation

If speciation is the instance of a new species coming into being, then natural selection is not a mechanism of speciation. It is rather the process that determines whether and how long the species population survives. --Ed Poor

So what is missing from the wikipedia entries on Darwin's theory of evolution is (a) identification of the process(es) by which an instance of a new species initially comes into being and also (b) distinction between this(these) cause(s) -- controversial -- and how well they survive -- not so controversial.

I'd also like to see a more clear separation between (a) Darwin's philosophical arguments and (b) the science. -- Ed Poor

Someone authoritative, like a scientist, please tell me whether Natural Selection (NS) is only (A) a weeding out process whereby AFTER a new species comes into being it survives or perishes or only (B) a process whereby new species originate; or if A causes B, or if NS = A + B. I'm not trying to be cute some of the articles imply one thing, some another, and I can't write Intelligent Design objectively unless I know precisely where it differs from accepted scientific theory. Ed Poor

Seems I recall someone telling me in early Dec 2001 that the following (which appears in the first paragraph) is not true:

Natural Selection indicate how new species come into being, how they survive, change or perish.

Shouldn't it be rather:

Natural Selection does not indicate how new species come into being, but how they survive, change or perish.

The change I propose (if LDC and other scientists agree) allows Natural Selection to be compatible with Intelligent Design while the existing sentence is causes difficulty. -- Ed Poor

I would say that the term "Natural Selection," per se, only implies that some natural force is selecting certain individuals in a species, and is to be contrasted with artificial selection, where humans either on purpose or by accident select for certain traits. However, the modern Theory of Evolution is not just natural selection. it is natural selection plus random change by genetic mutation. Of course, that's a wild oversimplification, but I think it generally gives you what you want here. --Alex Kennedy

I'm sure "Natural Selection indicates ... how they change" would mean to eventually change in to a new species? -- sodium

If I understand you correctly (and if LDC agrees), then it not Natural Selection per se but rather the theory of evolution which "indicates how new species come into being, how they survive, change or perish". The theory of evolution includes natural selection as the mechanism whereby after new species come into being or change they "survive or perish". Is this right, LDC, and may I change the evolution, theory of evolution, and natural selection articles to reflect this distinction? --[Ed Poor]]

That's generally right, but it's not quite that simple. Let me work on those articles and see if I can clarify them better. --LDC

The prose in "Natural selection" was a bit sloppy, so I tightened it up a bit. The other articles, though, Evolution and Theory of evolution, seem fine to me. They don't go out of their way to make a distinction between the "mechanism" of natural selection as narrowly construed, and the modern overall theory of natural selection which includes mutation, etc.; but then scientists don't often go out of their way to make that distinction, because it's not usually important. The Natural selection article probably should, and does; but the more general ones should remain general. Making the fine distinctions is something that only seems important to you (and perhaps other ID folks), and my understanding of the issue is only mine, so I don't think either one belongs in the major articles. --LDC

I removed this:

Perhaps the most radical claim of Darwin's theory of evolution through natural selection is that a set of random processes (including genetic mutation and natural disasters) can produce order. It is this fundamental claim that has inspired some of Darwin's most ardents supporters -- and that has provoked the most profound opporition. Some groups prefer to believe in divine intervention or guidance of the process; this is the "Intelligent design" school of thought.

We've already had this discussion: calling natural selection "random" is not only false, it is the 180-degree opposite of the truth, and has no place here. Mutation is random, selection is totally 100% deterministic. Every single one of your ancestors, without exception, was fertile, survived into pucerty, and chose to reproduce. Nothing random about that at all. --LDC

I rewrote the passage and re-inserted it. I did not originally write that "natural selection" is random, just that it involves random processes. Indeed, the original text refers to "non-deterministic" forces. In any event I trust that the current form is less controversial.

"Determinism" has been used in so many different ways I would hesitate to call even natural-selection "totally 100% deterministic." I'll grant that one can take natural selection as deterministic, but Darwin is clear that it is deterministic only in an immediate and local sense.

Please note too that I did not write the last sentence ("Some groups prefer..."); indeed, my contribution was meant to frame this sentence.

The bigger issue is that NOT every single one of my ancestors "chose" to reproduce, at least not in the same sense that you and I have chosen to discuss natural selection. If Darwin is right you and I share a one-celled organism as an ancestor that was not conscious (at least the way we are) and did not make choices (at least in our sense of the term. And I think this is what is at stake in the debate between Darwinists and Intelligent Design advocates -- whether the existence of consciousness today required a conscious creator (or designer). So I think it is important to recognize that Darwin's theory does not require such a principle. If someone else can find a more effective and accurate way to convey this I look forward to reading the next revision. -- SR

"Deterministic" is probably not the right word. Of course Darwin does not posit that 100% of your ancestors chose to reproduce, but he does posit that 100% of them did, in fact, reproduce; and that this feature distinugishes them from the 99.99% of all organisms throughout history that did not. Anything that's "100%" is not, by definition, random. Selection is immediate, precise, an brutal. And the reasons one animal reproduces and another does not are not entirely random--there are genuine differences, and those differences change the odds.

Your version is much better. "Random" is a fighting word.  :-). --LDC