unworthyone

How does natural selection work? It seems to be the only valid theory out there that still exists from the original state but the problem I've been seeing is that it almost makes "macro-evolution" impossible.

Natural selection cannot produce new genes; it only selects among pre-existing characteristics.

Daniel Brooks, as quoted by Roger Lewin, “A Downward Slope to Greater Diversity,” Science, Vol. 217, 24 September 1982, p. 1240

If this is wrong I'd like to see how.

Thanks!

[ April 05, 2002: Message edited by: unworthyone ]</p>

RufusAtticus

Hi unworthyone. Welcome to the SecularWeb. To answer your first question, I will direct you to a few pages on evolution. I recommend that you read them and bring any questions back to us. You should be prepared to scrap whatever concepts you have of macroevolution, microevolution, and evolution and pay attention to their scientific descriptions.

<a href="http://www.talkorigins.org/faqs/evolution-fact.html" target="_blank">http://www.talkorigins.org/faqs/evolution-fact.html</a>
<a href="http://www.talkorigins.org/faqs/faq-intro-to-biology.html" target="_blank">http://www.talkorigins.org/faqs/faq-intro-to-biology.html</a>
<a href="http://www.talkorigins.org/faqs/macroevolution.html" target="_blank">http://www.talkorigins.org/faqs/macroevolution.html</a>
<a href="http://www.talkorigins.org/origins/postmonth/jul01.html" target="_blank">http://www.talkorigins.org/origins/postmonth/jul01.html</a>
<a href="http://www.talkorigins.org/faqs/punc-eq.html" target="_blank">http://www.talkorigins.org/faqs/punc-eq.html</a>

Hopefully, after reading the above links, you will understand that macroevolution is evolution and natural selection is the major mechanism responcible. If you do not, we can help clear things up for you.

Edited to add:
Speciation (in most scientific senses of the word) is the result of reproductive isolation. Reproductive isolation is usually attributed to some physical isolation like geographic or chronolgical. Scientifically, the issue is not settled on how whether selection is capable of changing a panmictic population into separate populations that are not physically separate. (Panmictic refers to a population that effectively reproduces without any constraints on mate choice.)

-RvFvS
BTW: My email, which you can find in my profile, is always open.

[ April 05, 2002: Message edited by: RufusAtticus ]</p>

RufusAtticus

Unworthyone,

I found your quote at the top of this page, among other sites.

<a href="http://www.creationscience.com/onlinebook/ReferencesandNotes6.html" target="_blank">http://www.creationscience.com/onlinebook/ReferencesandNotes6.html</a>

Here at Infidels, we do not appreciate the tatics of quote-mining creationists. I do not think you are to blame. You have just been mislead by professional liars. I recommend that you read the following webpage before you pass to us anymore quotes lifted from anti-evolution websites.

<a href="http://www.talkorigins.org/faqs/quotes/" target="_blank">http://www.talkorigins.org/faqs/quotes/</a>

Thanx, -RvFvS

Godless Dave

Unworthyone, you'll learn a lot if you follow the links given above. But here's the short answer:

Natural selection doesn't create new genes. Mutation does (and yes, mutations do introduce new genes, which could be thought of as "adding information", despite what you may have been told). Natural selection is the process where those mutations are "selected". That is, if a mutation confers a survival advantage, it will be passed on to offspring.

Speciation occurs gradually over time. Donkeys and horses are different species that evolved from a common ancestor.

This is a big oversimplification from a non-biologist. I'm trying to put it in layman's terms in case the barrage of TalkOrigins links is too overwhelming.

[ April 05, 2002: Message edited by: Godless Dave ]</p>

unworthyone

Well I'm no expert, hence the quotes, as I stated originally. And you are no God, so I can choose to quote whoever I want. Please refrain from the demeaning tones, otherwise I'll just leave. Disprove my thoughts as you will, but I can only know what I read, as many others.

Also the book of reference is not a creationists book.

[ April 05, 2002: Message edited by: unworthyone ]</p>

unworthyone

I appreciate this as I need it in laymans terms.

unworthyone

Now I didn't see any of those links providing an actual observation of genes combining to created a new species. Can someone show me?

Pomp

unworthyone,

I'm a complete layman, but I've seen that quote in the past (in context), so I'm going to take a shot at an answer.

The intent of the quote you provided, I believe, is to express the observed fact that natural selection actually acts as a brake on genetic change. I've read that the natural mutation rate would completely destroy most genomes in relatively short order if selection did not have the stabilizing effect of selecting against most mutations. Well, most mutations that have a measurable phenotypical effect, anyway.

In other words, mutation provides more than enough variety to account for speciation, and selection usually acts to stabilize populations, keeping their genomes from wandering to far afield.

Again, I'm a layman, so I'm sure the more informed denizens will have more detailed information and/or corrections.

Asha'man

Hi there unworthyone, and welcome.

You are quite correct, posting quotes is fine, and pretty much required for the layman. And you included a reference, which is considered good form as well. A direct link to the original source is especially appreciated, if possible.

However, we at the II have often run into a particular type of quote posting, the misquote. This is considered to be very similar to lying, and therefore not appropriate for polite conversation, which is what we are trying to have. Many of the quotes that we have seen from creationists are really misquotes, and I think Rufus was just trying to politely warn you away from them.

As for your question of observations of speciation, there are a few, but not many. Almost by definition, evolution is a slow process, and not likely to be directly observed during a human lifetime. For the most part, evolution is indirectly observed, so every species that exists (or ever existed) would be considered an example. There are some directly observed examples with species that reproduce quickly, however, and I hope someone here can provide a detailed reference.

Additionally, direct observation of DNA sequences is a very recent technology. This again makes it unlikely that we have a “before” and “after” map of the DNA where a speciation event has occurred. I think it may exist for a few carefully studied species, such as fruit flies, but would have to do some searching.

unworthyone

But if it is a theory you must definately have a hope that if will be shown to be true at some point. But then how can you have a theory without being able to test it? Maybe I'm wrong but how do you test a slow process that may take millions of years to occur? And then give it the name of a "theory" without it being falsifiable?

[ April 05, 2002: Message edited by: unworthyone ]</p>