evolution, why not more variation?

[Ouroboros]

So, I really don't know what you mean when you ask for MORE diversity. I'm sometimes baffled, by how much there actually is out there, and you say that there had to be MORE?

Yup.

Just look at something simple as hops that used for bitters in beers. There used to be only some 10 variations 50 years ago, now there are hundreds. They are genetically different. Even though they've been selected and cross-bred by humans, the genetic variation is happening right there in front of our eyes.

Or take yeast for the brewing process itself. After 7 generations, you will have new kinds of yeast with different flavor. Even the yeast production company will tell you that. It varies by its own accord, just by natural process.

 

[Ouroboros]

Sure that's what occurred to me at first, "variations in a theme" we could put it. I don't know about bad design, however the question still looms imo.

Your talking about diversity within the gene pool then. Actually, it's quite interesting because you can look at the statistical variation to establish the age of a stable species.

The other thing you're talking about is speciation. Why isn't that happening more often? Because that's not a quick process as you suggested. It takes time, and it's not always obvious. You have to look at the small, small changes over a very long time.

Look into speciation, that's the term that's used in evolution for this event you're interested in.

Oh, and by the way, there's a couple, husband and wife, who studied the finches on Galapagos islands for 40 years (yes, the same island as Darwin was on), and they found new variations and speciations happening on that island. Boom. Ground finch and cactus finch, for instance. And yes, admixture is a form of speciation in this case, because the admixture is on the family level and not species. Two different species of same genus or family are still two different species, and even if they're compatible, they're not necessarily same species, and intermixing them produces a new species, a cross-breed.

There's so much to this topic.

 

[sun rise]

Just to start, there are on the order of 8.7 MILLION different species on Earth give or take a million or so. Then we have tremendous variation in homo sapiens- in height alone from 2 to over 8 feet (in adults), intelligence and much more.

 

[RichardParker]

Yup.

Just look at something simple as hops that used for bitters in beers. There used to be only some 10 variations 50 years ago, now there are hundreds. They are genetically different. Even though they've been selected and cross-bred by humans, the genetic variation is happening right there in front of our eyes.

Or take yeast for the brewing process itself. After 7 generations, you will have new kinds of yeast with different flavor. Even the yeast production company will tell you that. It varies by its own accord, just by natural process.

Sure, but as you say, this is the result of cross-breeding and artificial selection.
Of course, if you artifically select you get more variation than you would just in nature, because there you have natural selection, which eliminates variation that have a negative effect on the fitness.
But with artificial selection, you don't select for fitness, you can select for all kind of things you want to. And that's why you get certain variation that you wouldn't see occure naturally.

 

[Ouroboros]

Sure, but as you say, this is the result of cross-breeding and artificial selection.
Of course, if you artifically select you get more variation than you would just in nature, because there you have natural selection, which eliminates variation that have a negative effect on the fitness.

There are two major steps to the principle:

1. Increase in variation, which happens through random mutation
2. Selection, natural, sexual, or artificial.

The selection does not generate variation, it reduces the variation. Just like you're saying, natural selection eliminates selection. That's correct.

Not sure what you mean that it would have a negative effect on fitness, you mean artificial selection? Yes, that would have a negative effect on fitness for being in the natural environment, but since it's an artificial selection, the fitness is also artificial and since something is selected, it is therefore "fit" for that selection.

Nothing is fit for everything. Humans aren't fit for swimming in the ocean, hundreds of feet down, but whales and dolphins are. Whales aren't fit to fly, but birds are. Birds aren't fit to climb in trees, but chimps are. Chimps aren't fit enough to figure out how to build houses, but humans are. Fitness is depending on the specific environment.

But with artificial selection, you don't select for fitness, you can select for all kind of things you want to. And that's why you get certain variation that you wouldn't see occure naturally.

The selective criteria is the fitness in artificial selection.

Nothing is fit for all environments.

And variation doesn't come from selection but from mutation and recombination.

 

[RichardParker]

Not sure what you mean that it would have a negative effect on fitness, you mean artificial selection? Yes, that would have a negative effect on fitness for being in the natural environment, but since it's an artificial selection, the fitness is also artificial and since something is selected, it is therefore "fit" for that selection.

The selective criteria is the fitness in artificial selection.

Appologize, my wording wasn't that clear.
Yes, if "fitness" is ment in the sense of reproductive capabilitiy, then in artificial selection, you don't select against fitness, because the criteria by which you select will become the fitness-criteria.
I was more refering to pheno- and genotypes, that in natural environment would give disadvantages of survival.
F.e. we can select dogs to have all these skin flaps until they can hardly see out of their eyes. That's a variation, that, in nature, would seem to diminish the chances of survival extremly, since seeing is kind of important to these kinds of animals.
But when we artificiall breed them, we take away the risks and disadvantages that come with that phenotype, and therefore we can breed for something that you won't ever see in nature.

And variation doesn't come from selection but from mutation and recombination.

Ahhhhmmmm...
That's not entirely true!
Yes, variation doesn't come from selection, but the variety of animals you see in the wilde certainly does. Because selection eliminated all variation that had a negative effect in that environment.

So, you've compared the diversity we've had in f.e. hops before we started artificially selecting them, to the diversity we have today, and say it is much bigger. And you seem to ask, why it isn't as big in nature (at least that's what I got from your question). And the explanation is, that in nature you only have a small peak for fitness, while in artificial selection, we can create as many new fitness-peaks as we want, and therefore end up with a bigger variety.

 

[Ouroboros]

Appologize, my wording wasn't that clear.
Yes, if "fitness" is ment in the sense of reproductive capabilitiy, then in artificial selection, you don't select against fitness, because the criteria by which you select will become the fitness-criteria.
I was more refering to pheno- and genotypes, that in natural environment would give disadvantages of survival.

Of course, but that doesn't affect variation. The question was, "why not more variation?" And my answer is, there's quite a lot of variation, even within breeding and artificial selection, enough to produce new kinds of hops, dogs, wheat, corn, bananas, and so forth.

If that means that those variations aren't fit for survival in the wild, it doesn't change the fact that there's a huge amount of variation, and it can be observed.

F.e. we can select dogs to have all these skin flaps until they can hardly see out of their eyes. That's a variation, that, in nature, would seem to diminish the chances of survival extremly, since seeing is kind of important to these kinds of animals.

Depends. There are four categories of selective pressure. I don't have my book here right now, and I don't remember the names, but there are times when the selective pressure in the wild is a lot less. It depends on environment.

For evolution to work (I've done some software dealing with this) efficiently you have to have times when the selective pressure is much less to allow an increase of variation in the pool, then you can slowly increase the pressure and the variation decreases but fitness increases. If the pressure comes to quickly, you have an extinction event.

But when we artificiall breed them, we take away the risks and disadvantages that come with that phenotype, and therefore we can breed for something that you won't ever see in nature.

So? Doesn't change the variation.

Ahhhhmmmm...
That's not entirely true!
Yes, variation doesn't come from selection, but the variety of animals you see in the wilde certainly does. Because selection eliminated all variation that had a negative effect in that environment.

Increase of variation comes from mutations and recombination.

Decrease of variation comes from selective pressure.

I know this.

So, you've compared the diversity we've had in f.e. hops before we started artificially selecting them, to the diversity we have today, and say it is much bigger. And you seem to ask, why it isn't as big in nature (at least that's what I got from your question). And the explanation is, that in nature you only have a small peak for fitness, while in artificial selection, we can create as many new fitness-peaks as we want, and therefore end up with a bigger variety.

The hops we have today didn't exist before. Evolution is happening constantly. By growing hops and selecting a particular kind, you slowly moving the selection of the mutations you have and artificially create a form of speciation event, simply because you're creating a environmental niche of that hops. Over many generations, you end up with strains that have different DNA and different flavor. That's how it works. Those strains didn't exist 50 years ago, but they exist today, because of breeding of them (which is done by taking seeds from the ones that have a higher bitterness and plant those, then pick only the ones with higher bitterness from those, and so on, and by doing it many times, you select for the new strains of higher bittering genes, this is how they evolve new strains of yeast in the lab too).

The reason why I brought up hops is this:

There used to be only a handful of strains.

Now, there's at least 80 in commercial use, and they all produce different amount of AA%. How is that "not more variation"? I'd say 80 is more than, let's say 10. Don't you think? 80>10? More? If so, then more variation in just a simple area like that. Same with yeast, tomatoes, corn, ... There are new kinds of berries. New kinds of cows. New kinds of horses. New kinds of dogs. New kinds of ... Just in the last 100 years. That's more in my opinion, and not less. More variation means more variation, not less variation. Simple is that.

 

[Sapiens]

There are two major steps to the principle:

1. Increase in variation, which happens through random mutation
2. Selection, natural, sexual, or artificial.

The selection does not generate variation, it reduces the variation. Just like you're saying, natural selection eliminates selection. That's correct.

Not sure what you mean that it would have a negative effect on fitness, you mean artificial selection? Yes, that would have a negative effect on fitness for being in the natural environment, but since it's an artificial selection, the fitness is also artificial and since something is selected, it is therefore "fit" for that selection.

Nothing is fit for everything. Humans aren't fit for swimming in the ocean, hundreds of feet down, but whales and dolphins are. Whales aren't fit to fly, but birds are. Birds aren't fit to climb in trees, but chimps are. Chimps aren't fit enough to figure out how to build houses, but humans are. Fitness is depending on the specific environment.


The selective criteria is the fitness in artificial selection.

Nothing is fit for all environments.

And variation doesn't come from selection but from mutation and recombination.

Natural selection often can have a negative effect on fitness. Keep in mind that the change in genetics happens today but selection happens sometime in the future.

 

[sun rise]

Natural selection often can have a negative effect on fitness. Keep in mind that the change in genetics happens today but selection happens sometime in the future.

Sometimes the future arrives quickly as some variations are not viable, some cause the genetic diseases many have and some take a longer time to play out.

 

[LegionOnomaMoi]

So, anyways, with evolution, we supposedly have very 'fast' changes relatively speaking, in basic appearance, (think human variation) anyways, why not more variation? This question occurred to me a while back, and it isn't totally answered imo, there really doesn't seem to be a reason' for the limitations we observe in general.

For me, a better question is why we have any variation (or much of any). The most ancient forms of life are still around and in spades. The organisms most likely to survive anywhere (extremophiles) are very simple and all are relatively the same compared even to variance among "simple" multicellular organisms. Even among very complex living systems we find examples of species like sharks which haven't really "evolved" (in the non-scientific, common parlance sense of "qualitative change in a direction") for millions and millions of years, and even though we find great variety there is no real "reason" for the amount we find (that is, given evolutionary theory, the environments in which sharks live, the changes to these over time, and some generic "shark", a good model of the likely range of variations over time would vastly underestimate the actual variation found; another way of thinking about this is that many variations neither really decreased nor increased fitness functions yet were "selected" for nonetheless). Genetic mutations occur all the time, but most of these are fatal or harmful. Rarely do mostly neutral/benign mutations result in the kind of variety we find among e.g., sharks (see e.g., Elasmobranch Phylogeny: A Mitochondrial Estimate Based on 595 Species).

Unfortunately, both the term "evolution" itself as well as a good portion of the history of evolutionary biology have resulted in deeply rooted misconceptions, such as teleology, "direction", and generalized rather than environment-specific notions of fitness (not that there do not exist adaptations that are not environment-specific; the shedding of the lining of the stomachs as well as the production of antibodies in humans are both examples of traits which are not specific to a particular environment). Thus too often we find examples of thinking about evolution in terms of the ways in which species increase in complexity and "superiority" (often conceived of from an anthropocentric point of view).

In truth, from a "success" or "fittest" point of view, the most successful species are those that have been around since the beginning, and there is no particular reason to think that evolutionary processes need to have resulted in the rates, nature, and underlying bases for the mutations that are the foundations for adaptation/selection we find. Rather, the fact that most species that ever existed are extinct, but that the earliest remain, seems like evolutionary processes responsible for the variance we see are also responsible for the failure of most species.

 

[RichardParker]

So? Doesn't change the variation.


Increase of variation comes from mutations and recombination.

Decrease of variation comes from selective pressure.

I think you still don't exactly understand what I'm trying to say.
Yes, variation comes from mutation and recombination. That's true.

But imagine you have a (completly fictional, just for demonstration) animal-species with ceveral alleels for fur-color.
Brown, yellow, white, green, blue, pink, black and grey.

Yet, in nature, you have an extreme selection against all bright colors, so in nature you will find an extremly low variation. This species only shows brown and black coloration.
In selective breeding on the other hand, you can have the entire range of color I've presented above, because there was no selection pressure against the other colors, and a selective breeding process that selected for all of them.
So you end up with more variation in home-breed animals, in comparison to wilde animals. The different selection pressures let to a higher diversity in artificially selected animals, than in wilde ones.

THAT'S what I've ment, when I said that selection also can lead to different degrees of diversity. The hypothetical diversity we can have is determined by the genetics, but the actual diversity we see is determined by the selection pressure.

 

[Ouroboros]

Natural selection often can have a negative effect on fitness.

I know. And I did agree on that. Which means that it doesn't increase variation.

I keep on saying that variation comes from mutation, recombination, etc, not selection. Selection is the opposite. It's the reduction/decrease of variation. You have 100 individuals of different genotype. Select 1, kill the rest 99, how big variation do you have? It's easy to see that select does not increase variation.

My other point was that we have variation today, which we can see in all the new types of breeds of animals and strains of food. How we got it, that's not important, the only important thing here is that the question "why not more variation?" is ludicrous. We have a huge variation of many things.

Keep in mind that the change in genetics happens today but selection happens sometime in the future.

I do know. I didn't say otherwise. I'm not arguing selection. It's a sidetrack that had nothing to do with what I was discussing.

 

[Ouroboros]

I think you still don't exactly understand what I'm trying to say.
Yes, variation comes from mutation and recombination. That's true.

But imagine you have a (completly fictional, just for demonstration) animal-species with ceveral alleels for fur-color.
Brown, yellow, white, green, blue, pink, black and grey.

Yet, in nature, you have an extreme selection against all bright colors, so in nature you will find an extremly low variation. This species only shows brown and black coloration.
In selective breeding on the other hand, you can have the entire range of color I've presented above, because there was no selection pressure against the other colors, and a selective breeding process that selected for all of them.
So you end up with more variation in home-breed animals, in comparison to wilde animals. The different selection pressures let to a higher diversity in artificially selected animals, than in wilde ones.

THAT'S what I've ment, when I said that selection also can lead to different degrees of diversity. The hypothetical diversity we can have is determined by the genetics, but the actual diversity we see is determined by the selection pressure.

Ah. Ok. I get you know.

Yeah, I think it could be true. We end up with a larger variation in artificial breeding than in nature.

But, they've discovered that the genetic variation in sharks (one of the oldest stable species) is extremely large. Basically, there are a huge number of innocuous and analogous mutations, which doesn't show as a huge variation in the phenotype. So variation even exists there, but it's just not visible.

---added

Perhaps I just didn't get the question in the thread correctly. If we're just talking about variation of the phenotypes, there's this concept of peaks and valleys in evolution. When the environment or niche is stable, there's a tendency to find some kind of equilibrium of the species, and visible variation won't be as obvious. Like the shark. They own their place, their niche. Any mutation that varies too much from their established foothold, is selected against.

 

[idav]

So, anyways, with evolution, we supposedly have very 'fast' changes relatively speaking, in basic appearance, (think human variation) anyways, why not more variation? This question occurred to me a while back, and it isn't totally answered imo, there really doesn't seem to be a reason' for the limitations we observe in general.

This planet seems to have too many variations especially including the 99% extinct species on the planet. The biggest reason for any limitation is that this is a harsh planet by lifes standards. Apparently not as harsh as the other planets in the solar system but bad enough that 99.98% of species can't make it for more than a couple hundred thousand years.

 

[Ouroboros]

This planet seems to have too many variations especially including the 99% extinct species on the planet. The biggest reason for any limitation is that this is a harsh planet by lifes standards. Apparently not as harsh as the other planets in the solar system but bad enough that 99.98% of species can't make it for more than a couple hundred thousand years.

That's true. It reminds me about extinction events. There's been 5 major ones. In one of them, some 90% of the species in the world were eradicated.

There are some signs showing that we might currently be in the number 6. We might right now be in the middle of the next extinction event, which would mean that we're to expect a huge reduction in species and variations.

 

[Sapiens]

... expect a huge reduction in species and variations.

followed by a huge increase in variations and the number of species, that's the way it works ... only we may not be here to see it.

 

[Ouroboros]

followed by a huge increase in variations and the number of species, that's the way it works ... only we may not be here to see it.

Yup. It's followed by an explosion of variation. I think the most recent one resulted in the explosion of Mammals (I could be wrong though, can't remember everything. LOL!)

 

[idav]

followed by a huge increase in variations and the number of species, that's the way it works ... only we may not be here to see it.

Yes and somehow from the OP's perspective just no diverse enough. Of course we don't see more diversity since most of it didn't make and if it didn't make it its hard to see.

 

[Ouroboros]

Yes and somehow from the OP's perspective just no diverse enough. Of course we don't see more diversity since most of it didn't make and if it didn't make it its hard to see.

Still, there's probably more hues and shades of eye color than there are for cars. So I'm not sure how a huge variation, larger than options in the store, isn't large enough.

 

[idav]

Still, there's probably more hues and shades of eye color than there are for cars. So I'm not sure how a huge variation, larger than options in the store, isn't large enough.

I am with you on that. The diversity of humans alone, and we can all still mate. With dwarfs it isn't highly recommended because of complications but there are odds that two normal size adults can have dwarfs without it being in the parents genes, something like one in 10,000, not a huge number but the potential for diversity is certainly there. Anomalies are always to be expected but not to last when the planet is just as quick to kill you off for being different.