Specific Question on Evolution...

[sbbqb7n16]

How does Evolution explain the creation of sexual creatures/organisms? I know this has probably been discussed many times before, so please posts any links to other threads, and any counter-arguments here. Thanks

Problems I see with Sexual beings.

1. Sexual is worse off than assexual, being that it requires another mate of the same kind to continue the race/species/organism.
2. It would require that 2 of the same kind of being would evolve in the same place, same time and that they would mate with each other...
3. This mating would be have to be incest.... which is proven to increase the rate of birth defects...

Can't think of any more right now. If anyone has any more, please feel free to add to my list...

 

[Cantuar]

Haven't been around long enough to remember previous discussions, but the usual explanation is that sexual reproduction is a lot more efficient at removing deleterious mutations and combating parasites.

http://www.pbs.org/wgbh/evolution/sex/advantage/

 

[seebs]

I think the key is advantages. Let's say that you have a large population which reproduces asexually, and one member has developed feature A, which is useful, and one has feature B, which is also useful. There's no way for them to combine these! In a species with sexual reproduction, the winning traits can be *combined*.

This is a gigantic advantage.

(Personally, I'm quite glad we are of a species that reproduces sexually.)

 

[sbbqb7n16]

But it's all supposed to be about basic survival right? Now maybe having better features might be slightly better, but isn't population more important in the long run>? Plus you'd eventually evolve anyways in and of yourself right? Why are there no complex assexual beings? Why are the majority all one-celled? Guess I'll just have to chekc out that site

 

[LewisWildermuth]

If population is all you want to take inot concideration, not to worry the asexuals have us beat by miles in that one... If I remember the stats right there are more bacteria on and in you at this moment then there are humans on Earth, there are more asexual beings in one square mile than all sexual beings on Earth.

 

[sbbqb7n16]

From what I've seen the argument for sex is basically assuming that one would know where they would be eventually evolving. How can you do that if it all takes so much time?

 

[seebs]

The problem, I think, is that the original poster is laboring under the misapprehension that there's a "best" survival strategy. There are *many* survival strategies, each with different payoffs.

 

[seebs]

Originally posted by sbbqb7n16
From what I've seen the argument for sex is basically assuming that one would know where they would be eventually evolving. How can you do that if it all takes so much time?

No, that would be implying goal-directed behavior.

More likely, some asexually-reproducing species occasionally somehow combined genes from two members of the species - and this was enough of an advantage that the underlying trait of combining genes, itself, became more common.

 

[LewisWildermuth]

Or Seebs they have found that some single celled animals (and some primitive animals too) take on organells and things from the creatures they eat. I don't know if this happens with DNA but I don't see why not.

Nature eventualy found a way to internalise this process. First through self fertilization then through mutual fertilisation (earthworms still do this along with a few others) then a loose changeable sex identity (frogs and a few others) then the seperatons eventualy became compleat.

 

[LiveFreeOrDie]

Originally posted by sbbqb7n16
Problems I see with Sexual beings.

1. Sexual is worse off than assexual, being that it requires another mate of the same kind to continue the race/species/organism.

True, but the payoff is that sex increases genetic diversity. Over the long run this outweighs the cost of sex.

2. It would require that 2 of the same kind of being would evolve in the same place, same time and that they would mate with each other...

Not necessarily. Many primitive organisms have the ability to reproduce both sexually and asexually.

3. This mating would be have to be incest.... which is proven to increase the rate of birth defects...

If incest is bad, then asexual reproduction has to be even worse, right?

In fact, this is exactly the problem that sexual reproduction solves.

 

[Late_Cretaceous]

Bacteria and protozoa are not totally asexual. Just like the birds and the bees, those little critters do it as well. Bacteria sex, called conjugation, is often glossed over even in introductory microbiology courses but it is a very significant part of the life cycle.

We are biased to see microbes as being strictly asexual - it's always shown on those science class videos. Sexual reproduction in some form or another has been around since the earliest lifeforms.

 

[sbbqb7n16]

Originally posted by LiveFreeOrDie
True, but the payoff is that sex increases genetic diversity. Over the long run this outweighs the cost of sex.

True. I see how now. But here's another question about that then. Why only 2 sexes? why not more? That would provide a greater ability to mix and match characteristics right? Then wouldn't that be better?

Not necessarily. Many primitive organisms have the ability to reproduce both sexually and asexually.

Then why wouldn't they stay that way? That is by far the best way to go... because if you can't find a mate, then you can always reproduce with yourself and keep the race alive... why deevolve to only one or the other? And why have they not grown to the size of the more complex organisms by now?

If incest is bad, then asexual reproduction has to be even worse, right?

No. Asexual produces 2 identical copies of the first. Incest tries to combine two incompatible partners together causing many brith defects and the sort...Which raises another question...how does evolution explain incompatible blood-types for humans? Is this a prelude to a different race? Or just a difference among same species creatures

 

[seebs]

One thing you have to understand is that incest is only *statistically* bad. (And perhaps morally, but that's a separate question.)

 

[Jerry Smith]

Or Seebs they have found that some single celled animals (and some primitive animals too) take on organells and things from the creatures they eat. I don't know if this happens with DNA but I don't see why not.

You are right. Mitochondrial DNA most likely started out this way, as did the DNA in the chloroplasts of green plants. The DNA in the chloroplasts of green plants is especially significant because it is near identical to the DNA in cyanobacteria.

 

[sbbqb7n16]

Sorry Jerry you are assuming that these Mitochondria started this way. Hence "most likely".... But there is no such way to prove that, yet. And I doubt there ever will be...

 

[seebs]

It may be an assumption, but it's a fairly reasonable assumption, and has been used to form predictions, which have been tested.

 

[Cantuar]

Sorry Jerry you are assuming that these Mitochondria started this way. Hence "most likely".... But there is no such way to prove that, yet. And I doubt there ever will be...

When the possibility of endosymbiosis (eucaryotic mitochondria being the descendents of bacteria living symbiotically inside other bacteria) was first suggested, it was pretty much given the brush-off. But later, when techniques were available to analyse DNA and it was found that mitochondrial DNA was much more similar to bacterial DNA than eucaryotic nuclear DNA was, the endosymbiosis theory was taken a lot more seriously, It's now pretty much mainstream.

No, there's no way to prove it, but science isn't about proof.

 

[sbbqb7n16]

But nonetheless it is still an assumption and in no way rules out the existence of a creator, or shows an exact path where things came from. It is all speculation as of right now and has no firm foundation.

 

[seebs]

No one who actually accepts evolution has ever said it rules out the existence of a creatior. That's just a lie used to scare people off.

 

[Cantuar]

No, it isn't an assumption because it's backed up with the bacterial-DNA evidence. Before the evidence was available, the hypothesis was really not taken seriously. After it became available, it was. That's how science works - when a hypothesis makes predictions about data and those predictions are shown to be correct when the data come in, then you have a theory. NOT an assumption. Not a speculation. And a pretty good foundation. You can always do some reading on the background to endosymbiosis of you want to find out what it is and what its state of support is before jumping to conclusions.

Of course it doesn't rule out the existence of a creator, nothing in science rules out the existence of a creator. Science isn't in the ruling-out-creators business. A lot of evolutionary biologists are Christians.