My alternate view on evolution
Post Reply
 
Thread Rating:
  • 0 Votes - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
30-12-2010, 10:21 AM
RE: My alternate view on evolution
(30-12-2010 10:09 AM)latvianxave8 Wrote:  If DNA mutations are equally important to evolution than natural selection, then how is evolution not random, if DNA mutations are by definition random?

Because random DNA mutations are only one ingredient in the evolution recipe. The next ingredient is natural selection. Basically nature decides which of those random mutations are beneficial. Those mutations are then passed on to future generations. It's kind of like adding an ingredient to make things less random.

Look at it this way: just because you add sugar to a recipe, doesn't mean it's going to be sweet if there's other things in the recipe to offset the sweetness. In the recipe for evolution, there's random ingredients, but the outcome isn't totally random because theres other factors that temper that randomness.

Make sense?

Just visiting.

-SR
Find all posts by this user
Like Post Quote this message in a reply
30-12-2010, 10:23 AM
RE: My alternate view on evolution
I suppose.

Fight the system,

~~~but don't mute the opposition!~~~
Find all posts by this user
Like Post Quote this message in a reply
30-12-2010, 10:29 AM
RE: My alternate view on evolution
....buuuut.....?

Don't be shy. I'm happy to discuss it, and be challenged. Heck, maybe I'm missing something in your explaination that could help me understand evolution better.

Just visiting.

-SR
Find all posts by this user
Like Post Quote this message in a reply
30-12-2010, 11:12 AM
RE: My alternate view on evolution
Well, I'll stick with your analogy.

Having something in the ingrediants to counter out the sweetness of the sugar, doesn't take away from the fact that the extra sugar could be bad for you. Just like in evolution, having another factor that isn't random doesn't take away from the fact that one of the factors is random.

Fight the system,

~~~but don't mute the opposition!~~~
Find all posts by this user
Like Post Quote this message in a reply
30-12-2010, 12:08 PM
 
RE: My alternate view on evolution
I'm not following this analogy anymore and so I will not stick to it.

To state that DNA mutations are more important than natural selection is to apply a value to each one. Since applying a quantitative value to each one is foolish and quite frankly impossible, we must go with a qualitative evaluation. How exactly do you determine that one is more important than the other? By what methodology?

Natural selection cannot occur without mutations. And mutations cannot cause evolution, or expand beyond the scale of an individual organism without natural selection. So, I say they are equally important.

Evolution is not random. Mutations are random, yes. So, at an individual level, changes are random. However, evolution occurs at the scale of a population of organisms. A population of organisms is a localized group of organisms of the same species (they can breed with each other).

Natural selection is the mechanism through which mutations that occur at an individual level are transferred to the population. Up until this point, everything has been random. For the purpose of explanation, let us assume that the current generation of organisms in our population was spontaneously created, and thus inherited no naturally selected for mutations.

Let us also say that the initial genome of every organism within the population is identical, so the each organism, is at the outset equally suited to its environment. Now, throughout the course of the organisms' lifetimes, each one will receive random mutations.

Some of these mutations are beneficial. They increase that organism's ability to survive within its environment. The organism becomes more fit. Fitness is defined as the organism's ability to produce fertile offspring.

Some of these mutations are neutral. They occur in parts of the genome which scientists refer to as "junk." These sequences of DNA have no known role. Or perhaps mutations occur that alter entirely superficial things within the organism. All in all, these mutations have no effect on the organism's fitness.

Some of these mutations are harmful. Perhaps they make the organism infertile, or reduce its lifespan, or make it easier to be seen by predators.

So, after a few years of maturation, our batch of organisms is mutation-infested. For the purpose of explanation, let's say that 50 % of organisms developed beneficial mutations, 25 % developed harmful mutations, and 25 % developed mutations that have no effect on the organism. It is now time for them to breed. Organisms that have mutations that are beneficial will produce more offspring. Organisms that have mutations that are harmful will produce less, or they will produce offspring that are less likely to survive and produce offspring of their own.

So now we have a 2nd generation. The frequency of neutral mutations will stay roughly the same. The frequency of the beneficial mutation or allele will increase, since more offspring with that mutations have been produced. The frequency of harmful mutations will decrease, since less offspring that contain it have been produced, or have survived.

After successive generations, one will find that that the harmful mutation will become almost negligible within the gene pool, since organisms who receive it either die before being able to mate, or produce less offspring, or produce offspring that shortly die. This is natural selection. Without it, evolution cannot occur.

The population has experienced "evolution." There has been a change in the frequency of certain alleles within the gene pool. This evolution was not random. The population now is overall better suited to its environment than when it was spontaneously created. It did not change in a random direction, but in a direction that would make it more fit. The only random part would be the superficial mutations upon which there is no selection since they do not affect the organism. Over time, this may account for genetic drift, but once these neutral mutations no longer remain neutral, natural selection will again select for or against them depending on their effect on the organism.
Quote this message in a reply
30-12-2010, 01:57 PM
RE: My alternate view on evolution
(30-12-2010 11:12 AM)latvianxave8 Wrote:  Well, I'll stick with your analogy.

Having something in the ingrediants to counter out the sweetness of the sugar, doesn't take away from the fact that the extra sugar could be bad for you. Just like in evolution, having another factor that isn't random doesn't take away from the fact that one of the factors is random.

Correct. So the fact that there is sweetness (sugar) in the recipe doesn't mean that the final product is sweet. And the fact that there is randomness (DNA mutations) in evolution does not mean that the end product is completely random.

Just visiting.

-SR
Find all posts by this user
Like Post Quote this message in a reply
Post Reply
Forum Jump: