Are WE still evolving?

[h2whoa]

I'm a little confused here. Aren't we confusing evolution with genetic variation here? I don't see humans as evolving. We're still humans. What I do see is humans experiencing a normal range of genetic variation as all species do. We flux about a bit as the environments and social patterns change but such variations are alterable as you've all pretty much described. ... it's genetic variation. ... not evolution. ... right?

But this is the key issue. Boradly speaking, evolution is just genetic variation. Over time and with selective pressures these variations are dragged to one end or the other of allele frequencies. That is what evolution is. No genetic variation, no evolution.

Evolution is not some conscious decision that we make. "Oh this trait is desirable, so I'll evolve it". It's the natural outcome of selecting specific genetic variances over time. So it would be naive to say that evolution isn't still occurring in us on a broad timescale.

It might be true to say that evolution might have slowed in us because we occupy a new niche, created by ourselves. However, it's not a particularly stable niche we're in. We experience fierce intraspecies competition (war). We are exhausting the niche's resources, such as oil and sustainable food sources (to an extent). We've created new adaptive pressures. Instead of worrying about being eaten we have to worry about blood pressure and work-related stress.

 

[JDDCH]

No, Genetic Variation doesn't lead to a new species. It leads to different types of cats and different types of dogs. Different types of horses. ... It doesn't lead to new species. Genetic Variation only goes so far and either stops or turns around and goes the other way or veers off on a tangent for a while but it never leaves its origin. A duck will always be a duck. It may get a larger bill or a smaller bill to suit its environment, or change its feathers or alter its average body weight, but it will always remail a duck. It's genetic variation.

 

[JDDCH]

sorry, cross-posted with you.

evolution would be one species turning into another. that's not genetic variation, that's something entirely different.

 

[h2whoa]

No, Genetic Variation doesn't lead to a new species. It leads to different types of cats and different types of dogs. Different types of horses. ... It doesn't lead to new species. Genetic Variation only goes so far and either stops or turns around and goes the other way or veers off on a tangent for a while but it never leaves its origin. A duck will always be a duck. It may get a larger bill or a smaller bill to suit its environment, or change its feathers or alter its average body weight, but it will always remail a duck. It's genetic variation.

No. You're quite wrong. You really need to read up on evolution a little bit. I'm happy to help you as I am a geneticist. But first I think we need to understand your level.

If genetic variation doesn't lead to evolution, what does in your understanding?

 

[jwu]

No, Genetic Variation doesn't lead to a new species. It leads to different types of cats and different types of dogs. Different types of horses. ... It doesn't lead to new species.

And in the end these different dogs have accumulated so many genetic changes that they cannot breed with other dogs anymore. Speciation. This has been directly observed (albeit in other animals than dogs)

Genetic Variation only goes so far and either stops or turns around and goes the other way or veers off on a tangent for a while but it never leaves its origin.

What mechanism do you propose causes this, and where do you get that idea from?

A duck will always be a duck. It may get a larger bill or a smaller bill to suit its environment, or change its feathers or alter its average body weight, but it will always remail a duck. It's genetic variation.

Just like we humans still remain apes. And mammals. And vertebrates. And eukariota.

 

[JDDCH]

No. You're quite wrong. You really need to read up on evolution a little bit. I'm happy to help you as I am a geneticist. But first I think we need to understand your level.

If genetic variation doesn't lead to evolution, what does in your understanding?

I'm certainly no geneticist but I've spent 12 years behind the collegiate curtains and during my stay genetic variation halted at the species boudaries.

Evolution is one species forming from another. Evolution crosses that boundary from any point within.

Honestly, I've not really been able to grab hold of the evolution realm. I see genetic variation all the way, but I'm not so sure it can be called evolution.

From what I'm reading, the line of thought is that a species is pressed to an extreme through genetic variation and then forced across to evolution visa vis environmental pressures. Humans being haulted/slowed due to hitting a 'comfort zone' if you will within their environment. I'm just not entirely sure I understand it right.

I'm certainly not here to pic arguments. ... should probably get that one out. ... I just don't understand how it's come to evolution when I look at the same information and see genetic variation.

 

[h2whoa]

I'm certainly no geneticist but I've spent 12 years behind the collegiate curtains and during my stay genetic variation halted at the species boudaries.

Evolution is one species forming from another. Evolution crosses that boundary from any point within.

Honestly, I've not really been able to grab hold of the evolution realm. I see genetic variation all the way, but I'm not so sure it can be called evolution.

From what I'm reading, the line of thought is that a species is pressed to an extreme through genetic variation and then forced across to evolution visa vis environmental pressures. Humans being haulted/slowed due to hitting a 'comfort zone' if you will within their environment. I'm just not entirely sure I understand it right.

I'm certainly not here to pic arguments. ... should probably get that one out. ... I just don't understand how it's come to evolution when I look at the same information and see genetic variation.

At the crux of evolution is the idea that the definition, practically speaking is "evolution is the change in allele frequencies over time". It's more complicated than that, but it is, to my mind, an extremely important concept to keep in mind. Only those alleles which produce some kind of phenotypic variation (obvious or even quite discreet) can really be selected by the various selective pressures out there. This phenotypic variation could be something huge like a morpholical difference (i.e. an extra/missing eye) or something almost imperceptible (one nucleotide difference affecting the rate of transcription of a gene).

I think another important thing to remember about species evolution is that at the point at which two species diverge (which again is a long process, generally) it may be imposssible to tell the difference morphologically between the two species as they have so recently separated. Indeed, there are examples of birds for instance that people though were one species because they look the same but in fact turn out to be different. This arises through genetic variance. Now that those two species are genetically distinct from each other, each gene pool is closed to the other and divergent interspecies variation can take place. Extrapolate this with various speciation events throughout time and the possibilities are enormous.

Take this example. I have a square of 200 full-stops by 200 full-stops so there are a total of 40000 full-stops. You're asked to copy that square exactly, by hand, and then pass your copy onto someone else who will do the same. Whilst you're copying the square, you accidentally smudge on of the full-stops so it looks like a comma. You pass your copy on to the next person. They copy it, including your smudge, but accidentally smudge another full-stop to look like a comma. This process goes on for 40,000 people until your entire square is made of commas, not full-stops.

Now that's a very simplistic overview. Imagine instead that a couple of errors are in each copy. And instead of just adding commas, one of the commas is accidentally converted, by another smudge into a "g" or "j" or maybe "p". Then imagine that these are converted, through smudges, to "9" or "1" and so on. Sometimes, people accidentally leave something out as well. In very few generations you might end up with a grid that is no longer just full-stops, but 1s and 9s, gs, js, ps and commas. Maybe the grid isn't 200x200 anymore. Or maybe there's just a couple of gaps in that. The grid may no longer look anything like the original. It is completely different. Where it started as a defined grid of only one type of punctuation, it is now a grid of varying size, with various letters, numbers and punctuation marks making it.

That is the simplest way I can think of to picture evolution.

 

[JDDCH]

The concept is easy enough I guess. It's the practicality that's difficult to see. For me anyway. After all, a smudge on a paper is one thing, a living creature is a bit different. I don't suppose you could reccomend a text for me? Preferable one I can get electronically as I'm a bit of a mutant but if not I can have a hard copy delivered. I'd appreciate it if you could.

 

[h2whoa]

The concept is easy enough I guess. It's the practicality that's difficult to see. For me anyway. After all, a smudge on a paper is one thing, a living creature is a bit different. I don't suppose you could reccomend a text for me? Preferable one I can get electronically as I'm a bit of a mutant but if not I can have a hard copy delivered. I'd appreciate it if you could.

As I say, the example was just a visual of displaying the concept.

I think when dealing with genetics it's important to remember one thing: DNA is just a molecule. There is nothing inherently magical about it. That's one of the things that you have to do with molecular biology: get rid of all the philosophical presuppositions about life and remember that you are talking about molecules.

I think that sites people like to use are http://www.talkorigins.org and http://evolution.berkeley.edu/

It's difficult for me to recommend stuff on a genetic level because you have to remember that genetics is pretty much all I've focussed on since I was 18 and all of my colleagues are doctors and professors in genetics. Therefore it's hard for me to recommend from a lay-person's point of view.

One thing that I would like to add, which you may or may not know, is that evolution is not an anti-christian thing. The majority of Christians outside of the US accept evolution without a problem. I was a Christian up til about a year and half ago. Til I came to this site I wasn't even aware that creationism was such a vocal thing in the states.

 

[JDDCH]

Well, I'm not entirely a lay-person. I've been around the campus long enough to swing the jive ... although only a small portion of that, 3 years was spent within this realm and that was only as secondary studies. But anyway, thank you for the links. I'll check them out.

As for Evolution and the Bible, technically the Bible doesn't discount it. It doesn't speciffically discount evolution and I'm personally open to a combination of the two. Creationism and Evolution combined rather than pure evolution. I'd accept pure creation and I'd accept creation and evolution, but pure evolution is difficult for me to accept and as yet I haven't.

I'll check into those links and see if I can get some clarification so I'm not asking you to repeat yourself over and over again. Thanks for helping me out.

 

[michabo]

Evolution is one species forming from another. Evolution crosses that boundary from any point within.

Did you know that there isn't really a fixed, rigid boundary? As a population diverges, the genetic differences increase. Initially, they may appear sufficiently different that the two populations won't interbreed in the wild,but may be coaxed into breeding under artificial conditions. As the genetic distance grows, the two populations are less and less able to conceive. They may not be able to have offspring, or the offspring may be infertile. It doesn't take much of a stretch to see that this may keep changing until the species aren't able to interbreed, even artificially.

We see several examples like this in the world. Tigers and lions may be artificially interbred to produce tigrons or ligers, but these animals are often infertile.

Honestly, I've not really been able to grab hold of the evolution realm. I see genetic variation all the way, but I'm not so sure it can be called evolution.

Dawkins likens evolution to measuring a child growing. We can study cell division and see how children grow on a micro level, but this difference is miniscule on a day-to-day basis. If we weighted our subjects, measured their height or arm length, any growth from cell division would be lost in the noise of eating, excreting, and general living. But, over sufficiently long periods of time, it is undeniable that children do grow, and this growth comes from these miniscule changes in their cells.

So too with evolution. We can measure the changes in alleles, measure the phenyotypical changes in the population, and each generation they will probably swing from one extreme back to another, and so on. We can't see the progressive changes looking at a year-by-year basis just as we can't measure the growth of a child by measuring its height daily. But over many years, the change becomes undeniable.

 

[mr24shoe]

I posed the following series of questions to a YEC internet friend I engaged in a friendly email-based debate that eventually branched into this arena (continuing evolution of humans):
>====================
> (most of this info garnered from talkorigins, et al)
>1) Do you agree or disagree that we observe mutations
>in human DNA in the last 500 years? (VERY recent
>history on the evolution clock)
>(I'm hoping you agree)
>
>2) Do you agree or disagree that some of those
>mutations have been found to be beneficial?
>(I'm hoping you agree, due to evidence posted
>previously regarding:
>-Sickle Cell mutation (non-lethal version) resulting in malaria resistance
>-mutant allele of the CCR5 gene resulting in immunity
>to AIDS
>-resistance to atherosclerosis due to a mutation (This
>mutation is very cool because the person who had the
>original mutation has been identified.)
>-etc. )
>
>3) Do you agree or disagree that there has been a
>change in the population in certain areas due to these
>beneficial mutations?
>(I'm hoping again you agree, evidence from the
>mutations in #2 do indeed show population shifts, ie:
>the Sickle Cell mutation is prevelant in areas where
>malaria is more common)
>
>If agree to all 3, then you agree that Humans are
>(still) evolving.
==========================
I received as a reply the standard "micro vs. macro"; though I don't understand how one can accept micro, but not macro:
macro = micros + time
OTOH, I guess we are dealing w/ differeint "quantities" of time...

Interested in other's thoughts...

 

[h2whoa]

it may be imposssible to tell the difference morphologically between the two species as they have so recently separated.

FYI: These are known as "cryptic species".

 

[I_Love_Cheese]

Try using micro/macro economics, in the long run, the only distinction is the quantity of money.

 

[Loudmouth]

No, Genetic Variation doesn't lead to a new species.

Actually, it does.

Observed Instances of Speciation

Some More Observed Speciation Events

It leads to different types of cats and different types of dogs. Different types of horses.

That's what evolution predicts. For instance, humans and chimps are different yet still apes.

... It doesn't lead to new species.

See above.

Genetic Variation only goes so far and either stops or turns around and goes the other way or veers off on a tangent for a while but it never leaves its origin.

What stops the accumulation of genetic variation. For instance, every human is born with between 100 and 200 point mutations. This never stops.

A duck will always be a duck. It may get a larger bill or a smaller bill to suit its environment, or change its feathers or alter its average body weight, but it will always remail a duck. It's genetic variation.

And an ape will always be an ape. So do you deny common ancestory between humans and chimps?

 

[Edx]

I'm certainly no geneticist but I've spent 12 years behind the collegiate curtains and during my stay genetic variation halted at the species boudaries.

Where did you learn that? What "species " barrier? Perhaps you need to define "species" because apparently its something different.

Honestly, I've not really been able to grab hold of the evolution realm. I see genetic variation all the way, but I'm not so sure it can be called evolution.

Thats exactly what Evolution is. Speciation is basicaly where 2 populations get so different from each other they can no longer sucessfully breed fertile offspring anymore.

From what I'm reading, the line of thought is that a species is pressed to an extreme through genetic variation and then forced across to evolution visa vis environmental pressures.

This is not "the line of thought" at all, its a misrepresentation that Creationists like ICR, AIG and Kent Hovind spread and claim thats what Evolution is.

The first thing to realise is that if you learnt Evolution from a Creationist it invariably means you dont know anything about it.

Humans being haulted/slowed due to hitting a 'comfort zone' if you will within their environment. I'm just not entirely sure I understand it right.

We're still evolving, but its different because we have so much more control over our enviroment. That doesnt mean the biology is any different.

I just don't understand how it's come to evolution when I look at the same information and see genetic variation.

What you call genetic variation is evolution, you have this misunderstanding that evolution is something else where an organism crosses some kind of barrier with a different process. There is no other process.

 

[Gracchus]

Homo sapiens is building a large, diversified gene pool. The selective pressures are mainly sexual in the first world countries. ( It seems likely that AIDS resistance will be important in sub-Saharan Africa).

This will change when the inevitable environmental collapse that we have instigated by over-exploitation of resources, “cost-effective” pollution, and widespread marine extinctions we are causing by over-fishing. I suspect it is already irreversible. It may very well be catastrophic.

We cannot predict the exact nature or progression of the collapse, nor can we predict which phenotypic variations may prove beneficial. It may very well be that some phenotypic variation we don’t even currently recognize may be what is selected for. Or, it may be that the human species will simply become extinct, leaving no descendents.

 

[JDDCH]

zoiks ... everyone is picking one of my posts appart and having their way with me here. *sigh* I still don't agree ... but that's ok. pick all ya like. I guess it's just that noobi thing. maybe i'll try again later.

 

[Pats]

zoiks ... everyone is picking one of my posts appart and having their way with me here. *sigh* I still don't agree ... but that's ok. pick all ya like. I guess it's just that noobi thing. maybe i'll try again later.

Actually, JD, take heart

They're pointing out the scientific flaws in creationism, and subsequently your post. Not picking on you. Actually, most of the responses you've recieved here have been fairly polite and dealing directly with the science at hand.

You'll find that the evolutionists on this board out weigh creationists by more than 10:1 and they know their science.

Creationism isn't scientifically verifiable, it's more of a theology.

 

[LittleNipper]

Since, I only know about one theory of evolution. Which happens to be natural selection, I admit that I am somewhat ignorant on the subject. However, I understand that natural selection can no longer be applied to humans as we are now. So my question is; are will still evolving? What other theories are out there that I can read about. Anything that would help me find an answer? Any feedback is appreciated.

Yes, if that means that humans are becoming FAT AND LAZY.