“Evolution refers to the changes in heritable traits or gene frequencies populations; an individual organism cannot evolve.”

Your post’s Darmok are very clear and straightforward thank you.

I think this definition of evolution is a pretty good one. One I think with which I can work. Evolution refers to the changes in inheritable traits or gene frequencies in populations.

Now is THIS the evolutionary theory that you claimed earlier that is beyond dispute? Because if it is I can go with that. As a matter of fact I don’t think there are many people who would disagree with evolution defined as the change in inheritable traits or gene frequencies in populations.

However, in my experience most people blur this definition of evolution with the theory that Charles Darwin proposed. They don’t seem to realize that there is a difference between proof that organisms change through genetic and environmental circumstanstances and the inference that because of this therefore the diversity of all life is caused by this change.

It may not be an illogical inference, but it is not a direct cause and effect proof relationship.

I see it like this: A woman looks out her window and sees a child throwing a ball. She goes upstairs and comes back down stairs and her front window is broken. Of course, the first thought in her head is that the kid she saw broke the window. It’s not an illogical inference but neither is it logical proof that the kid broke the window. At best one can say the child did not not break the window.

In just the same way evolution, as we have agreed upon the definition, isn’t proof of darwins theory or one like it but just shows that it’s not incompatible. That’s the way I see it.

The purpose of the definition is precision. “Life change” is rather vague. For instance, I am a life-form and I have certainly changed over the years. I am taller than I was. My teeth are straighter. One of my bones has been broken and reset. However, I am not evolving. Evolution refers to the changes in heritable traits or gene frequencies populations; an individual organism cannot evolve.

The hair color to which you refer does represent a heritable trait (assuming neither of you have dyed your hair). However, the two of you are not enough to constitute a population. If we observed a population of humans, we might notice changes in the frequencies of different hair color over many generations. That would be an example of evolution. Over geologic time, we observe enormous changes, including organisms that differ so much that they are classified as separate species.

And you’re right: evolution, including the modern evolutionary synthesis (which includes mechanisms of evolution) is actually a pretty basic concept at its roots. Its simplicity is a big part of its elegance. In generic, basic form, we require A. (at least one) self-replicating entity, B. transmissible traits (with differential implications for survival), and C. imperfect transmission. The fundamental principles of evolution are quite basic and any entities meeting these criteria will tend to evolve.

Among Earth life-forms, genetic variation arises from several sources. Gene mutation is the classic one, especially when gene or chromosomal duplication has occurred and one copy is free to vary without adverse effect. Chromosomal abnormalities are another. Among sexually reproducing species, meiosis and sexual reproduction add enormously to genetic variety. Many unicellular organisms can exchange DNA in the form of plasmids. Also, many viruses incorporate themselves into host DNA; when they are excised for production of new viruses, they may take a piece of host DNA with them that then gets incorporate into subsequent hosts. Finally, the incorporation of primordial Rickettsia-like prokaryotes and of cyanobacteria-like prokaryotes as mitochondria and chloroplasts, respectively, are an example of a mechanism for major change. Taken together, these (and other mechanisms) provide for an enormous wealth of genetic diversity over geologic time.

Analyzing natural selection and the environment is complex, perhaps, but it’s not quite as complicated as you may think. The basic principle is simple: organisms who reproduce more will tend to have their genes become more predominant. In general, those that are the best-adapted to their environment will be the ones to survive.

Does that makes sense? It’s not my intention to confuse or obfuscate with specialized terminology, so let me know if I haven’t been clear.

Darmok, thanks for the response. Your definition of Evolution is quite understandable. However, there are a few things that are unclear to me.

“Observed change in inheritable traits or gene frequenceis in a population.”

Once again while this sounds “sophisticated” how does it differ from: “life change”. It certainly does not take a PhD in biology to observe that while I have brown hair my son has blond hair. It also does not require a degree to observe that certain population groups have certain tendencies.

Darmok wrote: “The mechanisms of evolution include gene mutation, natural selection, and genetic drift.”

I looked up each of these to make sure that I understood what you were saying. As I understand it gene mutation is a pretty “random” event. Natural selection is extremely difficult to predict because the environment plays a pivotal roll and the environment is constantly changing. Genetic drift is considered a statistical theory concerning the development of genetic traits.

So I want to make sure I am understanding you: Evolution, while sounding sophicated, isn’t much more than watching things change over time. The mechanism that drives this change is random chance (through genetic mutation and genetic drift), and environmental factors (which are too numerous to list here).

However, evolution does not explain the origin of life from nonliving matter. There are several plausible models for the origin of life on Earth, but they have nothing to do with evolution. Evolution requires an entity capable of reproduction and passing on (occasionally imperfectly copied) heritable traits. It does not explain the origin of such an entity (nor does it explain the formation of the Earth, quantum mechanics, or the photoelectric effect, and so on).

What a wonderful statment, I would like to know more about it.

When you say evolution I hope you mean more than “life change”- because that’s not a very “scientific” definition. I think the ancient Sumarians would have agreed that “life changes” It certainly doen’t take a PhD in biology to understand that life changes.

So what do you mean by “evolution”? Are you meaning the “theory” as posited by Charles Darwin? (I don’t think there are many individuals who believe a horse can have a baby with a longer neck because it stretched as an adult. In that case genetics’ disproves “Darwins theory”)

So what do you mean by “evolution”?
If I were to take my son out and show him a house and he asked me: “Dad how did this get here?” It would be extremely poor reasoning to say: “Well son lets take pictures out and look at this house when it was first built, then 15 years later then 50 years later and here poof there is the house.”
“Yes that’s the change of the house dad- but HOW did the house get here? What process happened so that there was NO house and then suddenly poof there IS a house.”

“Oh son, that’s easy, Men built it.”

Great: So how did life get here? Evolution. Great! but what is the mechanism that took nothing- and poof then there is life?

Since there is NO scientific debate concerning this topic it should be very easy to describe this process.

Anyway, I am ashamed at having let the conversation go so far afield. We were talking about evolutionary theory, which has nothing to do with the origins of life.
There is no credible scientific challenge to the theory of evolution. I don’t know if that can be said about the origins of life because I’m not as familiar with the current scientific position on that.

Sure, but they are still infinitely more probable than a supernatural omnipotent entity.”

Do I understand you to say that you agree life originating from inorganic matter faces high enough odds to be ruled impossible but you feel life from a creator is MORE impossible? Does that truly make sense?

Since either way it seems impossible, then why doesn’t the originated (or designed) thing itself count as evidence, just as a mansion on Mars would argue strongly for a builder, though unseen.

Mike said,

October 1, 2007 at 11:22 am

Actually I have a question: I was wondering how you all are dealing with Thomas Kuhns criticism of Evolution as a theory that is paradigmaticaly[sic] necessary to uphold a particular view of the universe; as opposed to being the definitative[sic] “truth” on the topic of life here.

Well, I haven’t heard it, and don’t understand what your sentence means.