C4 Diesel

No, I don't. The three conditions (no mutatons, no reproductive isolation, and no selection pressures) are all the requirements for NO evolution. Any one of the three will cause evolution (except in the case of reproductive isolation, which only CAN cause evolution).

A selection pressure alone can reduce the variety of alleles which qualifies as evolution.

Mutation alone can change the genepool directly by introducing changes in genes which are propagated through reproduction, eventually creating new alleles, which qualifies as evolution.

Reproductive isolation alone can also cause the dissaperance of alleles, although this usually requires a small population size (since it depends completely on random mating disparities without a selection pressure being present).

Since we have mutation, we have evolution. Do we have a retort?

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sapiens

This is slightly off topic and slightly addressed by someone else, but this thread is going in all sorts of directions... I imagine that the findings you express above might might be a result of restriction of range. You might not see many of those with really low intelligence, success, or beauty in your everday life. (Maybe you do, what do I know?).

You still may be right. I think that there is some evidence that lower IQ populations are outreproducing higher IQ populations in the United States. Higher IQ individuals more often attend college, sometimes grad school, postponing reproduction until their late twenties and early thirties. I'll have to look around for the evidence.

I met a wacky evolutionary biologist from South Africa who believed that women's breasts evolved to be flotation devices.... The Aquatic Ape theory of human evolution...

Suave

Evolution will never stop. In order for it (technically) to stop, (speaking for humanity) either a) everyone would have to die, or b) everyone would have to have an equal chance of having children with everyone else, as well as an equal chance of surviving. No matter how good medicine becomes, there will always be infant mortality, and there will always be people more prone to death than others. Likewise, no matter how good cosmetic surgery and everything else become, there will always be people more prone to getting laid and having children than others.

Even if we somehow (stupidly) decide to make everyone a clone of the exact same genetic makeup, eventually there will be superior mutations and evolution will be back on its way.

As an addition to the whole "IQ" discussion going on here, you guys have to realise that stupidity, propensity toward higher education, and many other factors are likely (it's debatable, but this is how I believe) much more strongly affected by social forces than biological ones. I'll leave spirituality completely out of this, but suffice to say that I believe that plays a part as well.

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Pacifier

No, I suggest nothing. It was just a though I wanted to add to the discussion.
Eugenics is certainly nothing I want to see.

yes, thats more what I had in mind, I believe that is something the humans will do in the near future. I don't really like the idea, but I think that would not stop anyone.
When the future mankind has the tools to improve humans body will they refrain from doing so?

really, no need to call me a nazi.
It just a thought I wanted to add to the discussion. Just a though and a question I wanted to see other reations to, since it would sped up evolution. But I agree the price would be too high.

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Dbass

The answer to the original question (I see nazism above, don't know where the thread has gone) is no. As long as people with down syndrome and dwarfism are mating (and they are), there can be no way for the defective gene to be bred out. I saw someone talk about this, basically unless someone has a fatal genetic disease they live and have a good chance of passing on the bad material. For example, Marfan's Syndrome, a disease that affects connective tissue, was almost completely caused by mutations before the 20th century. This means that before that time, anybody who had it died before they could pass on the condition, because of torn aorta or swollen brain casing. Nowadays, a comatose Marfan's sufferer can live into his/her 60's and easily pass on this genetic material, and as a result, we cannot evolve to not have it in the gene pool.
Basically, unless we just let dwarves, Turner syndrome-children, and all the other genetic-defectives die at birth, we won't evolve -- not that I advocate that!!!

CSflim

I just came across the following passage in the book that I am currently reading. It confirms the suspicions I stated in my previous posts.

- E. O. Wilson, Consilience (emphasis mine).

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Hain

Evolution ceasing is absurd. However as it has being pointed out:

and I happen to agree with Pacifier. Evolution is to be better adapted to the elements around one. Animals have evolved to either be capable of hybernating, have thicker fur or added fat, regrow tails, et cetera, but human beings have reached a point where we no longer need to adapt to our environment. In a similiar discussion, some mentioned to me that "Animals adapt to their environment--humans adapt their environments to fit them. We brute force them to fit us: Air conditioning, heated leather seats, remote controls--all of our environment are now created to fit us."

Humans have no need change when we can just alter the world around us to fit us. I had a good laugh thinking "humans can become so lazy that we've slowed down our own genetic evolution."

But some have said that because of medical advancements that more weaker genes pass to the next generation. I disagree with this because by looking at only 20 generations of time the average human life span has increased--because medical science has given us the power to defend our bodies from diseases. Many of the medicines effects stay with us and these benefits pass to the next generation.

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Hain

Reading some of the later posts sparked a memory of when I was at the Chicago Field Museum and there was a gallery of the Forbidden City in China. The topic was brought up about ancient China and how (as the conversation progressed) that the Chinese would murder children that seemed either to be retarded or have some kind of physically noticable defect. I hope that the others were making this up (these weren't museum guides, just visitors that seemed knowledgeable on China). I know that this topic of selective breeding came up in another topic about Dr. Mengele and his experiments.

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C4 Diesel

Just because the lifespan has increased doesn't mean that the people with "weaker genes" aren't passing them on. Medicine still does nothing to affect a persons genetic makeup.

And medicinal benefits are passed on to the next generation? Where is that coming from? Care to offer an example? ...Antibodies are usually passed between mother and son because they share the same blood (and later through breastfeeding), but the ability to produce those antibodies is generally not, hence why a child could get the same illness that the mother had and also why vaccines are still required in children regardless of whether their parents are immunized.

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reiii

This response is for Dbass, but addresses a few similar arguments in this thread.

Evolution is still alive and kicking. Ill give you a well studied example-

The sickle cell trait is conveyed by an incompletely dominant gene. People with two copies of the trait (one from each parent) suffer from sickle cell anemia, people with one copy, do not suffer from an acute disease, and are termed 'carriers'. Carriers have fewer functional red blood cells than normal people, but are able to live completely normal lives. Their unique blood make up conveys resistance to malaria.

The frequency of the sickle cell allele is many times higher in areas where incidence of malaria is high. This is an example of adaptive evolution, which occurred relatively recently. This is not the only epidemiological example that demonstrate the persistence of evolution.... the evidence is our there

edit: the first attempts at a post were a mess

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Seer666

Evolution is still kicking. Just look at Japan. The last couple of generations have been taller then the ones before them on average. Mostly due to change in diet, it is believed, I think. Have to look more into it.

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C4 Diesel

I don't think this is necessarily evolution in this situation. What I do believe is that the Japanese population already had the genetic potential to be taller, however they could not express that potential properly due to environmental factors (diet). Now that those factors are removed, the genetic potential can be fully expressed.

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ObieX

Intermingling of the different "races" can also be seen as evolution. Where there were once two seperate "races" now there's a "new" 3rd. Mating between an Irish man and an African woman would produce a child that is more resistant to the effects of the sun than the father (due to more pigment in the skin), and one that may be less/more likely to have something like sickle cell than the mother. It would also possibly mix the blue eye'd gene (if the father had blue eyes) in with darker skinned/haired humans where it would be seen less. While the child would have brown eyes (due to the mother having brown eyes and the brown eye'd gene being dominant), they would still carry the blue eye gene which could be re-introduced with the child's child depending on his/her mate.

Also i kinda get the feeling that when lots of folks think of evolution they think about humans suddenly growing a third leg or somthing. While this would be a form of evolution it's more common to see things that are slightly less noticable such as more resistance to diseases, infection, sun burn.. etc.

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C4 Diesel

Not if you define evolution in a scientifically acceptable manner. Merely creating different mixes of alleles is not evolution. New alleles must be formed in order for evolution to take place. As I've described earlier, such interbreeding of populations actually causes a genetic averaging effect which DECREASES evolution.

...Did you actaully read the whole thread?

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CSflim

Did this wacky person have an explaination for why males were so unfortunate as not to be endowed with similar floatation devices?

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Yakk

Look down. You have the vestigial leftovers of such a floatation device.

In men, life on land resulted in them evolving down in size. In women, their placement was such that it wasn't a huge disadvantage.

;-)

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ObieX

Yes i did read the whole thread, it just so happens i view evolution as a whole slightly different than you do. I see the introduction of new traits into a section of humanity where they were previously not present as a form of evolution. As sections of humans have evolved differently, the introduction of a new trait would be a different evolutionary path introduced to that section of human. You take an overview of all of humanity, i take a view that humans have already branched into different paths and view from those different splits.

...Do you have an open mind to different views?

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tecoyah

Evolution is a theory.......with many facets. The Idea that one interpretation is correct, while another is wrong defies the concept of theory. If by chance, anyone believes they hold the "secret" to turning evolution into Law........please write a paper and submit it to the scientific journal of your choice, after extensive peer review I am sure you will be given the support of your fellows.
As for this debate,perhaps an understanding of the innumerable levels on which evolution seems to act would be relevant. As it may garner a brief pause before offering opinion as fact.

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Hain

Is this genetic averaging real? I guessed it was because after a long period on our planet there is a diminishing diversity of genes in which to procreate with.

And for the post about medicine not passing on weaker genes: I am talking in relation to myself since I lack many of the illnesses and alergies that my parents suffer from. Either I am lucky or this type of thing happens more often than not.

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Yakk

There are many explainations.

Recessive traits tend not to be passed down to immediate children.

Things like alergies are very environment dependant: witness parents who refused to expose their young kids to peanuts, in an attempt to avoid allergic response.

Nutrition in youth matters alot to how healthy you are.

A combination of your parent's genes could have given you a less.. broken.. immune system than either of them. Complex things like immune systems are complex -- there isn't a gene that says 'your immune system is Level 30'.

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ObieX

Yea allergies are extremely environment dependant. And just because you aren't allergic to something one day doesn't mean that you wont become allergic to it the next. The human body "refreshes" itself about every 7 years, so after some time something that didnt effect you could start to effect you. Like someone could have a cat all their life, but then one day it'll start to make them sneeze and get a runny nose.

Genes are tricky to discuss. Some are dominant (if you have it it will always be the one used, like brown eyes) and some are recessive (you'll need a full set of that type for them to work, like blue eyes) and some work as a team. Height, for example, works with a few sets, if you have more for being tall you'll be tall if you have more for being short you'll be short, if you have a split you'll be medium height.

Parents that both have brown eyes can have a baby with blue eyes. And parents that are both short can have a tall baby (though that one is slightly less likely). With the eyes both parents would have to carry the blue gene, even though they may have this gene for blue eyes they also carry the gene for brown eyes - brown being dominant their eyes would be brown. It's easy to understand but i'l make a little diagram anyway cuz im bored :P

Parent A genes: Bl Br (brown eyed parent)
Parent B genes: Br Bl (brown eyed parent)

Their children could have any of the following combinations:

Bl Br (brown eyed child)
Br Bl (brown eyed child)
Br Br (brown eyed child)
Bl Bl (blue eyed child)

So basically a 1 in 4 chance of a blue eyed child.

However, if only one of the parents has the gene for blue eyes they stand a 0% chance of their child having blue eyes. If one parent is blue eyed and one brown, and the brown eyed person does not carry the blue eyed gene, the children still have a 0% chance to have a blue eyed child. If one parent has blue eyes and one had brown but has the gene for blue their child has a 50% chance to have a blue eyed child.

Anyway, people could have "evolved" traits that would never present themselves as well. If that gene is recessive it may never surface. Rarely is a mutated or evolved gene a dominant gene. A person could evolve the gene for orange eyes, but if that gene is recessive it would never show up if they had the gene for brown eyes. The gene could also be recessive compaired to the blue gene as well. So for this gene to show up the person would have to have a child with a person who also evolved this orange eye gene which would be EXTREMELY rare. And even then the person would only have a 1 in 4 chance of their child having orange eyes which makes it that much more unlikely that it will ever happen.

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Yakk

There is also the replication thing.

Lets say some gene tends to repeat. So you'll get
ABABCDCDAB ABABCDCDAB ABABCDCDAB ABABCDCDAB ABABCDCDAB ABABCDCDAB
repeated some number of times.

The number of such repetitions varies alot between parent and child, even if the gene was inherited. Apparently the number of such repetitions can determine some inherited conditions.

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1010011010

C4 Diesel Where exactly do you "teach this stuff to kids"? I want to avoid it like the plague when I start a family.

There are at least five (not 3) conditions that must be met for evolution not to occur in a population.

1) Infinite population size. Eliminates evolution from genetic drift.
2) Isolated Population. Eliminates evolution from gene flow from a population with a different genetic structure.
3) Random Mating. Eliminates evolution due in heterogenous allele distribution within the population.
4) No mutations. Guess.
5) No selective pressures. Eliminates evolution due to natural, sexual, etc. selection.

Intermingling of races does result in evolution (#2). The introduction of the alleles for caucasian features into an african population will indeed change the genetic structure of the poulation (mainly by introducing and increasing the frequency of the alleles for "caucasian traits").

I'm also mystified why people think that because humans aren't being eaten by bears or starving to death at the usual frequency, that there are no selective pressures. Humans are not adapted to living in a mordern urbanized environment. Either we'll fail as a species to maintain modern urbanized environments, or we will evolve to continue living in them.

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ibis

Dead? No.

The most recent (within millions of years) evolution humans have experienced in the mind.

Think of it this way, It used to be better for us to be really hairy. Once we gained the mental capibility to produce/maintain fire, we didn't need as much hair. Therefore a physical trait, like that of a desease, is trumped by a mental trait, like that of the capibility of discovering cures.

Evolution is well alive.

(The analogy may not be exactly precise, but it illustrates my point)

1010011010

ibis,
Your point seems to be to redefine evolution from a concrete physical process into an abstraction unrelated to the original concept except in name.

The capability of discovering cures, supposing it does have a genetic basis, will not protect you from disease. USING those cures will... but you don't need the capability of discovering them to use them.

All the groovy technological advances we've made have certainly changed the environmental stresses we're exposed to... and thus so do the directions in which natural selection will tend to move us, but I don't get the impression that's what you meant. It sounds like you're claiming the invention of the transistor is an evolutionary event.

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Yakk

Pedantic: It is an evolutionary event. Just not a biological evolutionary event!

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CSflim

That's just it. Evolution is an abstract process. That is why we can use evolution to solve complex computational problems which are untractable by other methods - the solutions are 'evolved' so to speak.

Evolution will occur anytime you have a group of replicators and
1. (imperfect) Inherritance
2. Variation
3. Selection Pressure

Check out the theory of memes. Its a bit, um, 'hokey', but interesting none-the-less.

For a book which elaborates on the ideas of 'Universal Darwinism' I highly recommend Darwin's Dangerous Idea by Daniel Dennett.

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Xell101

One of the things we humans seem most able to do is change the dynamics of the world around us. With the advent of agriculturalism a wider array of traits and skills became 'survivable'. This served as a swift kick in the pants to survival of the fittest. We changed the rules, you could now perpetuate your likeness throughout your collective of humans not by being the strongest, but by being able to sustain yourself in society. As society advancded the requirements for survival became more lax as we were more able to keep our fellow critters of civilization alive.

CSflim

You misunderstand what is meant by 'fittest'.
In evolutionary terms 'fit' does not mean athletic, strong, or high in stamina.

The fitness of a genotype is defined as its ability to survive (and raise children) in a given environment (which includes the phenotypes of all the other members of the population, and of all the other creatures living in the environment).

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Xell101

Ah balls, I phrased that very poorly. What I should've phrased that line to convey is this:
- Survival of the Fittest: Those able to survive and perpetuate the species given the circumstances, will do so. Those that can't, won't.
- Swift kick to the junk of the aforementioned idea delivered by civilization.
- Civilization as it exists today enables those that can't, to do so at the expense of the 'fittest'.
- Survivng at the expense of the 'fittest' doesn't count.

As a side note, what I meant by sustain is simply to not die.

Yakk

Um, you contradicted yourself.

- Survival of the Fittest: Those able to survive and perpetuate the species given the circumstances, will do so. Those that can't, won't.

- Civilization as it exists today enables those that can't, to do so at the expense of the 'fittest'.

Those that survive (and breed (and children breed (ad infinitum))) are the fittest. Thus, Civilization simply changes who are the fittest. By definition it cannot enable people who cannot survive to survive.

Which makes
- Survivng at the expense of the 'fittest' doesn't count.
a null-statement.

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Xell101

That's all on account of 'off' logic. Ill and zonked out on medicine you see. I was thinking of Survival of the Fittest as applying to a mode of life rather than the individual. A mode of life akin to a flying machine that only goes straight down.

CSflim

huh?
What is a 'mode of life'? And why are you redefining the meaning of 'survival of the fittest' so as to apply to it?
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Xell101

Mode of life = way of living.

Still rather zonked out so I'll just attempt to clarify. I was thinking of survival of the fittest as 'only' what life is capable of sustaining itself will go on. Didn't specify to what that applies, so thinking of groups of people living a certain way as sort of a living entity I applied it to that, which is the primary source of error.

1010011010

I think the problem is that when people think of "natural selection" they mentally draw a little box around humanity and lable it "not natural".

Certain ants keep aphids. They protect them from predators and stimulate them to secrete semi-digested plant sap (basically sugar water). It has been compared to humans keeping and milking cattle. AFAIK, they don't keep specialized breeds of aphids, but if at some other point the aphids evolved to be, basically, domesticated and dependent on the ants... are we going to call this "artifical selection"?

There's no more validity to talking about how living in a sky scraper is unnatural for humans than there is to talking about living in a termite mound as unnatural for termites. If you live in an urban/civilized environment, you will be subject to the selective pressures of an urban/civilized environment. This is natural selection.

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zen_tom

Thanks 666 - that's very true - I'd almost argue that technology is an extension of our evolved capabilities - If we lost all our technological enhancements and tried to live naked in the bush, few of us would survive, we've become so dependent on our technological nests.

One thing I read a while back (in one of the Jack Cohen + Ian Stuart books) was about the notion of Intelligence and Extelligence. Intelligence is what we can all agree we've evolved in the 'traditional' sense of the word - we've got big heads, manipulative hands, and are hardwired to look for patterns in otherwise chaotic data.

Extelligence however, is the accumulated knowledge of the entire race that is made available to us from our parents, society, media and now, the internet. It lets us draw on the mistakes and lessons that others have learnt and allows us to 'stand on the shoulders of giants' as Newton (I think) said referring to the great scientific minds whos ideas he'd used as a standpoint on which to base his own.

I think this secondary type of 'telligence - that really gives us our power over the world. We are truely benefitting from the labours of countless generations who have tamed the landscape, developed technologies to keep us warm, sanitary, satiated and entertained - and packaged up all the knowledge about how they did it for us to draw on and add our bit to the future generations that come after us.

If we were to loose this record of the past - if a genetically human baby were born in the wild. It wouldn't stand a fighting chance of survival - it would need raising - perhaps by wolves or apes or the like - the way a cukoo chick is raised by a bird of a different species.

I do think that the extelligence providing aspect of the human mind is what has got us here today. The attributes one needs for extelligence are sociability, intelligence, an ability for language and expression, memory, empathy and the ability to think from another's point of view. It is no surprise to me that these are often the same elements that people view as being important qualities in a life partner i.e. that the qualities that people prefer in a companion are the same qualities that help build the world we live in today. It's almost too simple. The reason we like these qualities is that it is built into our genetic makeup to do so - and the reason we live in the world we live in is because those preferences have been reinforced over generations and generations, which has allowed us as a species to invent the lightbulb, and gravity, and the Empire State Building and travel the world, and land on the moon, and enjoy internet forums.

0energy0

In my opinion, we keep evolving. Evolution never ends. The environment is always changing around us, so therefore we must adapt to these surroundings. This sounds like much like a science issue... hmm...

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pennywise121

ok, first let me relate to you a saying by my Developmental Psychobiology Proffessor Mathew Sharps (look him up, several books on development of cognition and gestalt/feature intensive processing theory). "Evolution doesnt have to work WELL, it just has to work."

with that in mind, are we evolving? Of course we are. But we are changing the way in which we evolve. over the past couple of pages, we have seen ideas put forth that humans adapt our environments to our liking (which we do), and that intermingling of the "races" is evolution (which it is not... more on that in a sec).

First, "race" is socially defined, and is an inane distinction for two reasons: 1. if i am your typical American mutt (mostly European), statistically i have more genes in common with a native African than with any Englishman. (if u dont believe me, look it up. there was a fantastic documentary on PBS years ago that did just that experiment). 2. True evolution is not a change in any individual, it must be on a species level. change in an individual is mutation (or the influence of teratogens), and it is only once the relative gene frequency within a population increases that it can be called evolution. the biggest differences between ethnicities are pysical features, and these are the result of environmental factors, so putting a resistance to sunburn into a person that lives in the modern world of sunblock accomplishes nothing.

now, back to the first point: we have adapted our environment to our liking, with many interesting side-effects. there is a 600% increase over normal in rates of autism in the central valley in California because of polution and pesticide use. nationwide, there are increases in fetal alcohol syndrome, cancers of all kinds, obesity. the list goes on and on. Individuals with Down's syndrome used to barely make it to adolescence, and now live into their 70s fairly regularly. can any of these be seen as evolution? not really. relative gene frequency is still way down on most of these (obesity not even necessarily genetic in nature). what we are seeing is the selective pressures against teratogenic influence and pesticide use, but we are trying to adapt our environment to fit our needs. what we end up with is the survival of genes that should by all rights and means have been fatal. the implications for this are not known by anyone, but it will be our children and our children's children that will learn the cost of our dealings with nature.

Food for thought