Actually, I see the rise of life on earth as a predictable response to the enormous amounts of negentropy pouring in from the sun, negentropy being the opposite of entropy. In effect, the sun is bathing the earth in stupendous amounts of orderliness, and life intercepts and utilizes a tiny fraction of that orderliness. I once did a calculation of the percentage of incoming orderliness is harvested by the biosphere. It turned out to be a tiny, tiny number.
Environmental sifting may be a good way of describing natural selection, but "survival of the fittest" is not.
That dubious piece of phraseology did not emerge from Darwin, but social philosopher Herbert Spencer, even before publication of the Origin of Species.
Thanks Sam. I didn't know that.
Yeah, there are so many freaking misnomers in the way we speak about biological evolution. It goes all the way down to the use of the term Theory of Evolution. Biological evolution is not a theory. Biological evolution is an observed fact. Natural selection, punctuated equilibrium, and Lamarkian evolution (acquired characteristics) are theories that attempt to explain the observed fact of biological evolution. Those are theoretical models to explain how the system works.
It's this fuzzy wording that leads creationists to say stupid shit like "Evolution is only a theory." They're wrong on two fronts. First off, their usage of the word theory is completely screwed. They're pulling out one of their favorite fallacies, the equivocation fallacy. We wouldn't even get to that point, though, if it wasn't for the fuzzy use of words.
Of course they would come up with a dozen new ways to misrepresent evolutionary theory, so it won't really fix anything.
Like Sam said, one of the important bits about evolution that isn't usually explicitly spelled out is that the system of evolution, particularly within species that make use of sexual reproduction, is best defined as the shifting of gene frequency within a given population.
I'm confused by your statement that biological evolution is an observed fact. It's true that we have observed change in at least one species due to alteration of the environment in which the species lives (the citrate experiment with E. Coli). And it is most certainly true that we have observed the results of biological evolution in the natural world. What I'm unsure of is whether we have observed the actual process of biological evolution in the natural world.
My own preference is to label evolution as a theory -- that is, a collection of ideas about a physical process -- that has been been demonstrated to comport with reality in a large number of variations. The people who point out that it's "only" a theory fail to understand what a theory is. The entirety of physics is nothing more than a theory, but the victims of Hiroshima and Nagasaki can attest to the power of this "theory".
We've observed speciation in the lab, along with pretty much every detail that makes biological evolution what it is. The fact of biological evolution is data and observations incorporated into the theories used to explain the nuts and bolts of the process. The process itself has been observed to happen, at this point, and some of the ancient Greeks proposed a similar concept, a couple thousand years ago.
You're free to call evolution itself a theory, but it's not. You're wrong to do so, in all but the most colloquial phrasing. The prevailing theory is Natural Selection, not Evolution. The most you could say is that it's the prevailing theory/model for explaining the process of biological evolution.
I'll sometimes slip, myself, and call it the Theory of Evolution, but it's rare, and I try to catch myself and correct it, when I say that.
Well, first off, a word or phrase means what people intend when they use it, regardless of the complaints of pedants like me. I cringe whenever I hear somebody use arrogant to mean proud, or use try and instead of try to. But that's the way the linguistic ball rolls.
There seem to be two points of confusion here, concerning 1) the meaning of the word theory and 2) the applicability of the term evolution as opposed to natural selection.
On the first point, I'm quite confident in claiming that the distinction is between a theory and an observation; the use of the term fact gets us into some unnecessary semantic complications. There is also, of course, the problem that most of our observations have some theory built into them. For example, if you read a thermometer at 5ºC, you're actually observing the location of the edge of a red bar, but our physical theory tells us that this location is a reliable indicator of the temperature. In any case, this is a point too fine to expend much energy on.
On the second point, professionals have a variety of terms with specific meanings applying to specific aspects of the overall theory. I can't think of any single term that incorporates the whole shebang (descent with modification, natural and sexual selection, Mendelian genetics, punctuated equilibrium, DNA, speciation, and so on), other than evolution. For example, natural selection refers to the process leading to speciation.
The governing fact here is that most people -- including biologists -- use the term evolution to refer to the entirety of the theory. Look at the titles of textbooks: if that term weren't academically correct, there wouldn't be so many biology textbooks using the word that way.
Chris, another example of evolution observed in nature is the peppered moth. For example, see
I had known about the peppered moth example long ago, but then got confused by the brouhaha over creationist attacks on it. The Wikipedia article explains the case quite clearly.
Napoleon, Kindly translate this for me!
It may be that the term survival of the fittest did not originate with Darwin, but I still think it expresses an evolutionary idea, viz., if a mutation results in a species being more fit to survive in its environment I think that might count for survival of the fittest.