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Author Topic:   How is Natural selection a mechanism?
dwise1
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Posts: 3868
Joined: 05-02-2006
Member Rating: 3.3


Message 4 of 191 (522566)
09-04-2009 2:03 AM
Reply to: Message 1 by AndrewPD
09-03-2009 7:02 PM


I think this was mentioned before, that some creationist classes require its students to join forums and make a set number of posts "challenging" evolution. What was that number? 20?

Where are you attending and which class is this for?

Now, let's try something really bizaare and unexpected. How's about you actually try to learn what evolution is and what evolutionary theory says? That would really throw a wrinkle in your professor's plans, since his goal depends on keeping you ignorant of what evolution really is.

PS
OK, first you apparently revived Darwin's mistaken "pangene" ideas, which were based on his misunderstanding of heredity (since they didn't yet know about Mendel's work -- I'll post about that on that thread). Now you try to claim that mutation is all there is to evolution and natural selection has nothing to do with it -- which seems to harken back to the early 20th century when mutations were thought to be it, but then the Grand Synthesis circa 1940 united genetics with natural selection via the mathematical study of population genetics.

So far, all you're offerring is gross misconceptions which look an awful lot like a troll's flame-bait. Do you really have no idea what evolution is about? OK, it should be a given that a creationist has no idea what evolution really is. But are your opening posts really what you think evolution is?

If so, then you have a lot to learn. Are you here to learn? If you are, then a lot of members here will be more than happen to educate you. Including a lot of former creationists who learned the truth.

Edited by dwise1, : PS


This message is a reply to:
 Message 1 by AndrewPD, posted 09-03-2009 7:02 PM AndrewPD has not yet responded

  
dwise1
Member
Posts: 3868
Joined: 05-02-2006
Member Rating: 3.3


Message 5 of 191 (522567)
09-04-2009 2:47 AM
Reply to: Message 1 by AndrewPD
09-03-2009 7:02 PM


Aren't mutating genes the sole mechanism by which organisms are formed?

No. In the early 20th century, geneticists rejected Darwin, in large part because of his mistaken ideas about heredity, and they had discovered mutations. So they pursued the idea that evolution was all through mutation, an idea that has been perpetuated through popular media, such as the X-Men movies.

But then in the 1930's and 1940's, biologists realized that mutations were only one mechanism for increasing the variability of a population's gene pool, whereas it was natural selection that still drove evolution by working on that variability. Thus was the Grand Synthesis and thus was neo-Darwinism.

AndrewPD, we've known for more than 70 years that it's more than just mutations. Isn't it time that you came up to speed on what's what?

One of the products of that Grand Synthesis (or, more properly, part of what had brought about that Synthesis) was population genetics, the mathematical study of how genes spread through a population. Which is key to answering your other question about new traits getting "diluted" (which harkens back to Darwin's misunderstanding of heredity and which led to his mistaken theory of "pangenes").

May I suggest a book? Blueprints: Solving the Mystery of Evolution by Maitland A. Eddey and Donald C. Johanson, Penguin, 1989. It goes through the history of the development of the ideas about evolution. It even gets into the reasoning and the experiments behind the different ideas and discoveries. If your Christian college is at all honest, then you should be able to find it in your library. If it's not there, then look for it in a local state-run college or university's library.

Now for a really heretical thought: Truth is truth; facts are facts.

If your theology really embodies Truth, then why does it need to lie about the facts? Does the Truth ever need to depend on lies?

Now to get really heretical. Instead of using lies and deceptions to attack evolution, why don't you simply learn everything you can about evolution so that you can use evolution's real problems against it? Not the facile lies that creationists teach you, but rather evolution's real problems. But to learn what those are, you will need to actually learn what evolution actually is. And what the evidence actually is. Are you ready for that challenge?

A word of warning. No creationist has ever been able to do that. So far, every creationist who has actually done all that has, to my knowledge, ended up rejecting creationism for being an outrageous pack of lies and deceptions. And I know of none of them who has not left his religion because of it. Sure, some of them have been able to remain Christian, but not fundamentalist Christians. And many of them have followed the dictates of their fundamentalist training and have become atheists, but that's the fault of their religion, not of evolution.


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 Message 1 by AndrewPD, posted 09-03-2009 7:02 PM AndrewPD has not yet responded

  
dwise1
Member
Posts: 3868
Joined: 05-02-2006
Member Rating: 3.3


Message 11 of 191 (522773)
09-04-2009 7:27 PM
Reply to: Message 6 by AndrewPD
09-04-2009 7:01 AM


Rather than try to think of evolution as something abstract and arbitrary, take the time to observe life and how it works.

In a given area/region, there are populations of plants and animals. Within each population there are individuals who are capable of interbreeding. If we were to examine the collective genomes of a population, which we generally call its "gene pool", we would find a degree of variation between the genomes of the individuals. This we refer to as "genetic diversity" or simply as "variability". When individuals mate a produce offspring, their offspring will be very similar to the parents, yet a bit different. Depending on the species' biology, these differences would be largely due to the different possible combinations of genetic material from each parent (eg, in diploid sexual reproduction, such as humans employ, each parent has 23 pairs of chromosomes and it's a crap shoot which chromosome of each pair each parent contributed to the child). However, some of the genetic differences can also be due to genetic mutations (please note that the only mutations that matter in evolution are heritable ones). Thus, the genetic diversity of the gene pool has been increased.

OK, observor, what do you see happening? A lot of offspring are born, yet a lot also never get born. Not every seed germinates and not every fertilized egg comes to full term. But still, there a an awful lot of offspring out there ... at first. But we observe that in most species of animal that most of the offspring do not survive to sexual maturity; in many species, the vast majority do not make it. As we observe, we can see what some of the individual reasons are, even though we cannot observe them all. We can figure out some of the individual traits that enhance an individual's chances of survival, while others can be more challenging to figure out.

That part is what evolutionary theory deals with as natural selection. Natural selection per se produces nothing new, but rather it tends to filter out the existing traits that diminish one's chances for survival. But note that natural selection is not something that actually exists and exerts force, rather it is how we think about the effects of how individuals survive until they have a chance to reproduce or don't. That "don't" can also apply to sexual selection, which is whether the individual will be chosen to mate, something that is so important in some species that it has profound effects on the appearance and behavior of individuals.

Those offspring who do survive to sexual maturity and who get selected to mate then produce their own offspring. Who are very similar to their parents -- ie, whatever traits the parents had which had enhanced their survival, a number of the children should also have -- and yet are a bit different. And so the cycle starts again.

What we observe is an interplay between reproduction which increases variability and selection which diminishes variability. It takes both for evolution to work.

So then evolution is our description of how life works. Even if we had gotten parts of it wrong, life still works the same way it always has.


This message is a reply to:
 Message 6 by AndrewPD, posted 09-04-2009 7:01 AM AndrewPD has not yet responded

  
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