Poaching making China elephants evolve tuskless

[BillHoyt]

Evolution is change in a creature.

Yes.

It may be phenotype or genotype. It may be due to genetic drift.

Sorry. The phenotype is the expression of the genes, as modified by both gene regulation and the environmental context. Evolution heppens only through the genes, although, as you stated, it can happen without affecting phenotype. It never affects phenotype without affecting genotype. This understanding marks the advent of the neo-darwinian synthesis and put the final nail in the Lamarckian coffin.

 

[Jas]

But don't elephants use their tusks in foraging? I wonder if this is localized to areas where certain foodstuffs are more readily available? Would one see a shift in where the elephant population is the highest?

 

[tracer]

It was said that a person judges a face to be beautiful base on how common it is to him/her. The beauty queen's facial feature looks common. Not ugly, not unexpected. It is uncommon to have a lady with only one eye on the face, thus she will not be considered beautiful.

Experiments have confirmed that many of the traits considered "beautiful" and "ugly" are hard-wired instincts, not the result of experience.

Babies will spend more time looking at the faces of supermodels than at the faces of "plain" or deformed women. (I saw it on the Discovery Channel, so it must be true! )

 

[Anti_Hypeman]

Dont they Poach some animals for the magical powers of their wangs? I wonder if they will evolve.

 

[IllegalArgument]

Experiments have confirmed that many of the traits considered "beautiful" and "ugly" are hard-wired instincts, not the result of experience.

Babies will spend more time looking at the faces of supermodels than at the faces of "plain" or deformed women. (I saw it on the Discovery Channel, so it must be true! )

I would suggest the BBC documentary "The Human Face". There's a section on beauty, the golden ratio and symmetry play a big part.

 

[Doghouse Reilly]

No references, sorry, but more recently the idea that beauty is closely linked with "symmetry" has been questioned. Even without references (which do exist) I believe that my statements will be fairly self evident.

Consider that a beautiful person is also beautiful in profile, and an unattractive person is still unattractive in profile.

Symmetry is not visible in profile, and yet the most beautiful people are still strikingly beautiful when no symmetry can be seen. If a beautiful person had half their face burned badly, and they covered it up, you would still recognize the other half of their face as beautiful.

Some of the most attractive people I have seen have had faces that were not so symmetrical....and each half was beautiful and the combination was beautiful as well.

I find it strange that symmetry was ever considered to be the main factor determining beauty. It's so easily proven wrong.

Almost any beautiful thing or person in the entire world still has its beauty intact when the factors making symmetry observable are removed. And almost any ugly thing or person is still ugly if symmetry is artificially created.

An interesting sidenote: Skin smoothness and texture play an ENORMOUS role in perception of beauty. I was shocked to see average or relatively unattractive faces becoming astonishingly beautiful when their skin tone was artificially smoothed with a computer program.

It's to the point that one interprets the face itself as exceptionally beautiful, even though previously the face appeared normal or even unattractive.

Of course bone structure and shape also contribute. But symmetry seems to come in far behind.

It seems more that symmetry makes faces more appealing than the same faces lacking symmetry. But to extend that awareness to the conclusion that symmetry is what makes beauty is highly dubious.

It's also true, as mentioned by another poster, that in beauty there is strangeness.

The idea that beauty comes from familiarity is mistaken, at least when taken to the extent that the perception of beauty is directly caused by familiarity.

Comfort and pleasure come from familiarity, but this should not imply beauty, and least not in the meaning in which we're discussing it.

Comfort and ease and a certain feeling of contentment and pleasure are to be found in those things familiar to us, but the reason we turn and stare at a beautiful person (or at least desire to) is precisely because that beauty is NOT familiar to us, and is something we DON'T see in those normally around us.

 

[Doghouse Reilly]

I am not a scientist, and am a layman when it comes to understanding what evolution "is" and "is not."

But I was under the impression that evolution was very dependent on the mutation of genes creating new features that were not previously found in a particular species.

So I can see why religious folks and laymen would be skeptical of the claim that this was "evolution in action."

If a new mutation caused some elephants to be tuskless, and then this group survived while those with tusks perished, then I think that very few would declare that this was not evolution.

I suppose it's the desire or the idea or the hope of seeing evolution in action actually CREATING something new, something that wasn't there before. Tusks were always sometimes absent, and now there are simply more elephants with that absence present.

It's no wonder, considering how this is emphasized in basic science textbooks. The idea of genes mutating and creating individuals with features that had previously been unknown, which happened, by coincidence, to be useful, is one that is difficult for many to believe, simply because it seems so fantastical, to us who have not ever observed it.

I would love it if someone can point me to examples where this has been observed...where a mutation has been observed in present day to confer benefit upon some species to the point that the trait has become dominant. Does such a case exist? Or is it only observable in the fossil record or is it theory, compelling, but not supported by direct observation?

I have to admit that it does stretch the limits of my gullibility to imagine that a mutation happened to confer some benefit countless hundreds of millions of times over the eons, when in modern life it seems that every mutation confers some harm.

I believe in evolution because I have not been exposed to any alternative idea that is reasonable, but I am sometimes a bit incredulous and find this theory too, quite unreasonable. I usually tend to assume that I simply don't understand it well enough, and that there are people who have worked out all of my objections....but I don't like to take things on faith.

I would be grateful to hear comments on my layman's perception, but I understand if perhaps that's more appropriate for another thread, or if perhaps it's merely a sign that I need to read more....any recommendations?

 

[Alkatran]

I am not a scientist, and am a layman when it comes to understanding what evolution "is" and "is not."

But I was under the impression that evolution was very dependent on the mutation of genes creating new features that were not previously found in a particular species.

So I can see why religious folks and laymen would be skeptical of the claim that this was "evolution in action."

If a new mutation caused some elephants to be tuskless, and then this group survived while those with tusks perished, then I think that very few would declare that this was not evolution.

I suppose it's the desire or the idea or the hope of seeing evolution in action actually CREATING something new, something that wasn't there before. Tusks were always sometimes absent, and now there are simply more elephants with that absence present.

It's no wonder, considering how this is emphasized in basic science textbooks. The idea of genes mutating and creating individuals with features that had previously been unknown, which happened, by coincidence, to be useful, is one that is difficult for many to believe, simply because it seems so fantastical, to us who have not ever observed it.

I would love it if someone can point me to examples where this has been observed...where a mutation has been observed in present day to confer benefit upon some species to the point that the trait has become dominant. Does such a case exist? Or is it only observable in the fossil record or is it theory, compelling, but not supported by direct observation?

I have to admit that it does stretch the limits of my gullibility to imagine that a mutation happened to confer some benefit countless hundreds of millions of times over the eons, when in modern life it seems that every mutation confers some harm.

I believe in evolution because I have not been exposed to any alternative idea that is reasonable, but I am sometimes a bit incredulous and find this theory too, quite unreasonable. I usually tend to assume that I simply don't understand it well enough, and that there are people who have worked out all of my objections....but I don't like to take things on faith.

I would be grateful to hear comments on my layman's perception, but I understand if perhaps that's more appropriate for another thread, or if perhaps it's merely a sign that I need to read more....any recommendations?

Ah the good 'ol "Oh, I believe in micro-evolution. But macro-evolution..."

Bacteria developping resistances to drugs is an example. There's also lots of genetic algorythms used in computing, which runs on the same principle as evolution (mutation and selection) and has been used to actually invent things.

 

[Doghouse Reilly]

You may have misunderstood me....I stated that I DO believe in evolution, and of course have not seen any theory or idea that comes close to competing with it.
I was attempting to point out that, for those of us who are not well educated on the subject, there are aspects of the theory that are difficult to comprehend or grasp.
I personally don't feel that our schools do a good job at all of presenting evolution in a manner in which it is particularly compelling.
Which is why I asked for reading recommendations.

 

[aggle-rithm]

I saw a show recently about how elephants are becoming increasingly hostile towards humans as we encroach on their environment. It said that the tuskless elephants were especially dangerous. This is explained by evolution as well: In order to survive, an elephant with no tusks has got to be seriously aggressive to beat out tusked males in their struggle to get the females. These aggressive, tuskless males then pass on both the no-tusk and the aggressiveness genes.

 

[BillHoyt]

But I was under the impression that evolution was very dependent on the mutation of genes creating new features that were not previously found in a particular species.

This is a common misconception, Doghouse. Except for recombination, which necessarily has to happen in diploid specied, there is no requirement for mutations to happen. The only necessary change is a change in allele frequency.

If a new mutation caused some elephants to be tuskless, and then this group survived while those with tusks perished, then I think that very few would declare that this was not evolution.[/b

Per the definition, it is evolution. Perhaps you really mean that it is not speciation, that is, the change to a new species.

I suppose it's the desire or the idea or the hope of seeing evolution in action actually CREATING something new, something that wasn't there before. Tusks were always sometimes absent, and now there are simply more elephants with that absence present.

It's no wonder, considering how this is emphasized in basic science textbooks. The idea of genes mutating and creating individuals with features that had previously been unknown, which happened, by coincidence, to be useful, is one that is difficult for many to believe, simply because it seems so fantastical, to us who have not ever observed it.

I would love it if someone can point me to examples where this has been observed...where a mutation has been observed in present day to confer benefit upon some species to the point that the trait has become dominant. Does such a case exist? Or is it only observable in the fossil record or is it theory, compelling, but not supported by direct observation?

There seem to be two things here. First, the question of mutations causing beneficial change. I have no idea why you think that, although I know many people share this misconception. Could you give me more on why you have this perception? Second, the call for direct observation of speciation. To my knowledge there have been several dozen directly observed speciation events over the past century+. There is a list of these that you can find on talkorigins.org

 

[Soapy Sam]

Sorry. The phenotype is the expression of the genes, as modified by both gene regulation and the environmental context. Evolution heppens only through the genes, although, as you stated, it can happen without affecting phenotype.

Here we get into the re-entrant multi level argument. What's meant by "through" the genes? Is it genes which evolve, or creatures? Both , of course- though we may choose to study one or the other, or both.
And species evolve in a sense- within , as you say, the environmental context. The removal of a major species from the environment affects the development of everything else.
That was my point about shooting the females. After 100 years, there are no more elephants. Have they "evolved"? Well, they've gone extinct, which is certainly one effect of evolution. There has been no genetic change in the elephants though- but there has indeed been a change in allelle distribution. (ie there aren't any left). Whether we choose to apply the word in this context or not seems to me a matter of preference.

I know we can't redefine terms to suit our mood, but terms must have some tolerance too. As Humpty said -"Which is to be master?"

It never affects phenotype without affecting genotype.

Absolutely never? I wonder. I'm not that confident there are no exceptions that prove the central dogma. Time will tell. (No, I don't know of any. Maybe it's that word "dogma" that bothers me...)

This understanding marks the advent of the neo-darwinian synthesis and put the final nail in the Lamarckian coffin.

Oh the Chevalier is alive and well. Amazing how very often the "evolution" that certain types refuse to believe in turns out to be Lamarckian. I'm never sure whether to agree with them, or smack their silly head.

[/B]

Doghouse- I think this illustrates the problem of teaching / understanding you describe. Bill and I are pretty much in agreement on this subject, I believe; but there is room for some diffference in views of what is and is not evolution.

The gene-only view is the view preferred by microbiologists, geneticists and strip club bouncers. ethnologists and geologists and zoologists tend to take a broader view.

Except Cladists, who should be thrown to the Inquisition and strapped in the comfy chair.


We won't fall out over it, but some people take the variation and pretend there is a void of disagreement.
Not so.

 

[BillHoyt]

The gene-only view is the view preferred by microbiologists, geneticists and strip club bouncers. ethnologists and geologists and zoologists tend to take a broader view.

Soapy, soapy, soapy!

How does evolution proceed somatically, rather than gametically? The last people I can think of who proposed that were the Lysenkoists in the now-gone U.S.S.R. and a very tiny band of Aussies, led by Ted Steele.

I am, of course, omitting cancer, monoclonal antibodies and the like because those somatic "evolutions" remain in the parent organisms, rather than passing across generations.

 

[Jas]

No references, sorry, but more recently the idea that beauty is closely linked with "symmetry" has been questioned. Even without references (which do exist) I believe that my statements will be fairly self evident.

Another point is when you take the same halves of people's faces and put them together (ie. two left side). They look really deformed. There was an article in some beauty magazine where they did it to a lot of top models and sex symbols, and their faces didn't have any sort of symmetry.

 

[Rolfe]

I sort of backed out of this discussion because I disagree with Bill, but I can see that we'll just have to disagree.

You can find all the biologists you like who are prepared to use the word "evolution" where only a shift in allele frequency in a population is happening, and this Chartered Biologist (and Fellow of the Institute of Biology) will disagree. Obviously this process is part of evolution, and evolution couldn't happen without it, but in and of itself I do not define it as "evolution".

The fact is that every time an individual dies or one is born, the frequency of alleles within the population of that species changes - although only very slightly. However, given this fact, how do you define an "evolutionary" shift? At what point does the normal variation due to the constant change in the individuals making up the population become "evolution"? Perhaps you've just said that all populations are constantly "evolving" under this definition, but in my view if you've said that you've said nothing, and rendered the term almost meaningless.

If no new genes are ever introduced (by whatever means), then the amount of change you can possibly get is strictly limited by the genes already available. You will never get an antibiotic-resistant bacterium, for example, if the gene for antibiotic resistance isn't already present in the population. You can go some way, particularly as regards losing characteristics, but you'll have a lot of trouble acquiring new ones.

Basically, if allele shift is all there is, evolution as it is normally understood simply can't proceed. Now if you want to say, ah, but what you are describing here is not evolution, it is speciation, then first no, not exactly (I'm including introducing new characteristics into an existing species without it becoming a new species), but second, is this a wise semantic distinction to make?

This definition is devaluing the concept of evolution. If you are happy to take something as minor and unremarkable as an allele shift and call it "evolution", and trumpet such an event as "evolution in action, yah boo sucks creationists!" then I feel you're setting yourself up for exactly the response you're likely to get. That if that's what you mean by evolution, then back to the drawing board pal, because it isn't enough to explain the origins of the teeming variety of life we see around us.

Yes, this is largely semantics, and I can't force someone who disagrees with me about the meaning of a word to agree. But I think the limited definition as it is being proposed here is a shot in the foot.

Rolfe.

 

[MRC_Hans]

Speciation is a word that constantly pops up in debates like these and in debates with creationists (I notice none of the residential creationists have piped in, yet). We keep discussing if this or that leads to speciation, but do we have a sure-fire definition of species? The most seen is "the ability to produce viable offspring", but that doesn't work for two reasons (at least):

- It has obviously only been tested on a fraction of the species we recognize (not to mention the possible combinations).
- There are in fact some species that can interbreed and produce viable offspring (most notably among fresh-water fishes).

So, do we have a workable definition of speciation?

Hans

 

[Soapy Sam]

How does evolution proceed somatically, rather than gametically?( Responding to BillHoyt).

Look at it from the point of view of a population biologist. Perhaps a 19th century one who had never heard of genetics.
Bodies are all he is interested in.
Absolutely, one part of the underlying causative mechanism is the genes, but what selects the genes?- The effects of the environment on bodies (where other bodies , often of the same species, are part of the environment.)

From that standpoint, ALL evolution happens to bodies, at the body level.
And that's a perfectly workable definition.

I feel both you and Rolfe are trying to pin down a precise definition of a process which operates on several levels, between which there is feedback. Every such attempt I have seen ends in a cul de sac of exceptions.

I feel we gain little and lose much by trying to pin evolution down to any single aspect. To pin it down to allelle frequency is an unnecessary restriction.

Likewise, I don't see "new genes" as either necessary for or definitive of "evolution". New combinations of genes are certainly a major cause of evolution, (ie of somatic variation on which selection can work), but what , actually would constitute a "new" gene?

Both parts, but neither approaches the whole. It's a bugger.

As for "species" , I'm with CRD- the difference between "species" and "variety" is whatever humans need it to be. Labels are tools we use, not straitjackets we must wear.

 

[MRC_Hans]

*snip*
As for "species" , I'm with CRD- the difference between "species" and "variety" is whatever humans need it to be. Labels are tools we use, not straitjackets we must wear.

Unfortunately, such a position will enable a creationist to claim that whatever evolution we point to is "just micro-evolution", since, according to his current fancy, a Zebra and a Horse (or whatever) are just "variations" of the same species. Been there, dunnit; some of them get the number of "true species" on board Noa's Ark down to a thousand or so, claiming that the millions we see today are just variations. ..... Yes it is silly, but..

Hans

 

[Rolfe]

Likewise, I don't see "new genes" as either necessary for or definitive of "evolution". New combinations of genes are certainly a major cause of evolution, (ie of somatic variation on which selection can work), but what , actually would constitute a "new" gene?

This is a very interesting point of view. Could you explain it in more detail, especially as regards what these new combinations of genes might do? Any relevant examples?

Rolfe.

 

[Soapy Sam]

Hans- True, but if we start defining terminology to exclude the arguments of the lunatic fringe , we may as well quit now. Species is a definition with a certain tolerance. That's life.

Rolfe- I smell a trap...I am not about to teach ma grannie how to suck eggs.

I don't think I mean anything radical.
I'll give you an analogy:-
Most genes act as switches to start or stop protein assembly.
Some switch on other genes.

Some switch on other genes, IF and only if yet other genes are also operational.

If you go to a DIY store and buy new light switches, does it matter if you use brass effect or plastic or steel effect switches?

It may- especially if you get the wrong loading for power circuits. But if they are viable at all, the switches will probably prove to be interchangeable.

Fitting a plastic one affects the appearance of the network, but does not affect whether the lights work.

End analogy.

Genes are code strings. Some are ancient and very stable.
These tend to be critical. Change them and you get monsters- major assembly / timing errors. In nature, they don't make it out of the egg.

Some are interchangeable, like light switches. Shift allelles all we want, it makes no odds. The switch still works.

Some don't do anything.

I don't think point mutations play a large part in evolution.
(Compared to sexual selection, environmental selection and sheer luck)
I don't think "new" genes are important.
I also think the preponderance of convergent evolution implies that there are some genetic solutions - and only some- that are any use at all.

However, we all know that recombination and jumping of coexisting genes in or between chromosomes makes a difference to the phenotype. These are modules that have stood the test of time in each other's company. Mix and match may not always work, but it stands a better chance of working than adding something wholly new to the mix.

And now I must run because I'm late. (and because I sense the wrath of god about to fall).