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mvp
Apr. 8, 2012, 05:15 PM
Below in italics is the original post for this very old thread, dusted off for various OT Days.

Now the thread has been resurrected in honor of the "33% of Americans don't believe in evolution" thread.

Look, I don't care whether you believe in the theory, and the science, and/or the possibility of ever proving the truth of evolution. All are welcome.

It seems to me that before one can have a good conversation about whether or not one should believe in evolution or not, or whether evolution and God need to be antithetical to one another, a body should get a good understanding of evolution. The thread is already long, and lots has been discussed by many expert COTHers. You might find some of your questions answered here. Or you can pose a new question/gripe/whathaveyou.

Put 'er here!

As a professional historian of this science, I'm Just. So. Done. with people giving simple and inaccurate accounts of Chuckie D.'s theory.

But it's my job to help you guys do better if you want.

Ask away. Anything/any period of evolutionary thought is fair game.

Hecklers are welcome, of course.

LauraKY
Apr. 8, 2012, 05:22 PM
I can't wait, my daughter is a physical anthropologist, her research professor is an evolutionary biologist. And we live in Kentucky. Her undergrad requires a natural science in its gen ed courses because so few students come from Kentucky high schools having been taught evolution. I guess if they can't teach creationism, they refuse to teach anything.

DeucesWild11
Apr. 8, 2012, 05:35 PM
I am an atheist and a pro evolution person, however I have a question; why, if things are constantly evolving why aren't there any "in between" stages, do example, an ape in the in-between stage of the evolution to man. Sorry if this is a dumb question.

xeroxchick
Apr. 8, 2012, 06:01 PM
Why do systems become more complex instead of becoming simpler?
How do parasites exist if they kill the host?
Is life on our planet natural or is a planet with life an infected planet? Like mold on an orange? Is the natural state of a planet to be barren?

Blugal
Apr. 8, 2012, 06:04 PM
If we do ourselves in by nuclear eradication, is it true that all that's left will be cockroaches and Stubben Siegfrieds? :cool:

Big Day
Apr. 8, 2012, 06:15 PM
This may be my most favorite OT thread ever! No questions yet, but I cannot wait to see the answers to ones already asked!

mvp
Apr. 8, 2012, 06:24 PM
I can't wait, my daughter is a physical anthropologist, her research professor is an evolutionary biologist. And we live in Kentucky. Her undergrad requires a natural science in its gen ed courses because so few students come from Kentucky high schools having been taught evolution. I guess if they can't teach creationism, they refuse to teach anything.

Great! And bad!

I ask my undergradlings if they were taught any form of creationism in HS, or "Naturalistic Evolution as one theory among others." In most parts of the US, the answer is no: It's Orthodox Darwinism all the way, or otherwise, any form of creationism is looked down upon.

But! The latest round of Creationism-- the Intelligent Design Movement which enjoyed a heyday from about the late 1990s to the Dover v. Kitzmiller trial in 2005-- was smart! Those guys asked some questions left hanging out by orthodox Darwinians.

And! Your average Gen Ed Science or General Evolution course won't do a fantastic job of presenting this complicated science in its present state. I have watched these at 3 universities. They present the established and simple.

mvp
Apr. 8, 2012, 06:32 PM
I am an atheist and a pro evolution person, however I have a question; why, if things are constantly evolving why aren't there any "in between" stages, do example, an ape in the in-between stage of the evolution to man. Sorry if this is a dumb question.

A very good-- if 19th century question.

To be clear, I have to back up some. Darwin's theory has two parts: That species change over time; and a causal explanation that explains how they change over time.

Because Darwin touted ancestral-descendant relationships for species and insisted that evolution process is gradual, his theory (as he put it in 1859) predicts smooth gradations of form between related species. These should show up across space-- say across a territory and decidedly in the fossil record.

So the basic answer to your question has two parts:

We don't see those "transitional forms" in the fossil record because it's a rather coarse and uneven "transcript" of life's history. Not all species leave fossil representatives.

Also, one can ask "How fast is 'gradual'"? How fast does the evolution of characters distinguishing species change with respect to geologic time?

19th century paleontologists got a lot of milage out of predicting and finding smooth series like the horse phylogeny.

mvp
Apr. 8, 2012, 06:38 PM
Why do systems become more complex instead of becoming simpler?
How do parasites exist if they kill the host?
Is life on our planet natural or is a planet with life an infected planet? Like mold on an orange? Is the natural state of a planet to be barren?

I'll take a shot at all of them....

The standard explanation for the evolving complexity of life changes depending on the morphology or organism you are talking about. For the evolution of eukaryotic cells or things like sponges or even symbiotic relationships between modern species, the answer tends to be "Division of labor among all whose survival gets easier."

For cool stuff like eyes and wings, it has a great deal to do with 1) What "heritable variations" (genes) can be brought into combination; and 2) The environment that establishes the rules of competition for survival and "reproductive success" (leaving lots of offspring that, in turn, live to reproduce themselves).

Well-adapted parasites *don't* kill the host.

I do like the idea of an infected planet. I never thought of it that way. I can't speak to big cosmological stuff. I don't know if planets have a "natural state." There are some reasons to *not* think that all planets are similar, ergo no single "naturalness" to consider at all.

mvp
Apr. 8, 2012, 06:41 PM
If we do ourselves in by nuclear eradication, is it true that all that's left will be cockroaches and Stubben Siegfrieds? :cool:

Yes.

Count on it. Bet on it. Too bad you won't be there. Too bad currency won't exist any more. But if you can find some post-Apocalypse endzone to do a dance in, I suggest you get nekkid and let 'er rip.

Celebrate your having been right because you'll die of radiation sickness or starvation or heinous mano-a-mano fighting with your species surrounded by toilet seat saddles and bugs.

mojo7777
Apr. 8, 2012, 06:47 PM
If we do ourselves in by nuclear eradication, is it true that all that's left will be cockroaches and Stubben Siegfrieds? :cool:

BIG laugh out loud on this one!

My dumb question: How did humans evolve such big craniums when it makes childbirth so risky for the mother? Seems like smaller craniums would select out because mom/baby would survive--over the larger craniumed, more intelligent.

FitToBeTied
Apr. 8, 2012, 06:53 PM
Where did all the stuff come from that created the big bang?

IronwoodFarm
Apr. 8, 2012, 06:58 PM
My turn!

So Dawin's theory is assumes natural selection. What about unnatural selection -- where will that get us? We have mapped the humane genome, we are beginning to develop more personalized medicine, we can clone animals......where is all of this going? It strikes me as it may end natural selection (admittedly not too soon) eventually assuming we manage not to blow the place up first.

nccatnip
Apr. 8, 2012, 07:03 PM
What if the Hokey Pokey is really what it's all about?

Bluey
Apr. 8, 2012, 07:04 PM
My turn!

So Dawin's theory is assumes natural selection. What about unnatural selection -- where will that get us? We have mapped the humane genome, we are beginning to develop more personalized medicine, we can clone animals......where is all of this going? It strikes me as it may end natural selection (admittedly not too soon) eventually assuming we manage not to blow the place up first.

You forgot inserting genes from one species into another.;)

"Natural selection" is not a constant.

We didn't know genes are not immutable until not so long ago.
Many of them can be altered by the environment too, to the surprise of many.

There is more to this than straightforward changes.

tasia
Apr. 8, 2012, 07:26 PM
What if the Hokey Pokey is really what it's all about?

:lol:

mvp
Apr. 8, 2012, 07:37 PM
My dumb question: How did humans evolve such big craniums when it makes childbirth so risky for the mother? Seems like smaller craniums would select out because mom/baby would survive--over the larger craniumed, more intelligent.

The usual story: The benefits of a Fat Head outweigh the risk of not being born and killing your mom in the process. Other parts to the story-- the ladies tolerated a wider pelvis (bad for running) in order to "compromise" and be able to give birth. Also, we have a cool feature: The sutures in the human skull and come unglued for a sec. and allow those plates to slide over one another in the birth canal.

And then there's also the idea of "heterochrony"-- the rates of individual development for different features of an organism. Given genetic control over features that are related during development but not necessarily in adaptive function, we get some notable but evolutionarily-irrelevant "extras." That has a great deal to do with what proves most important to survival over the whole life of an organism.

In all cases, we accept trade-offs: The risk that some Fat Heads will die in childbirth while the rest of the Slightly-less Fat-Headed-with-Big-Bootied-Moms will enjoy the benefits of a huge brain.

mvp
Apr. 8, 2012, 07:40 PM
Where did all the stuff come from that created the big bang?

The Big Bang preceded anything evolutionary.

I don't do cosmology nearly as well as I do history of biology, but you'd have to find some folks talking about the intraconvertability of energy and matter. Or read the Bible. Take your pick.

mvp
Apr. 8, 2012, 07:47 PM
My turn!

So Dawin's theory is assumes natural selection. What about unnatural selection -- where will that get us? We have mapped the humane genome, we are beginning to develop more personalized medicine, we can clone animals......where is all of this going? It strikes me as it may end natural selection (admittedly not too soon) eventually assuming we manage not to blow the place up first.

Let's get one thing straight!

Darwin based N.S. on A. S.-- artificial selection-- or really, what some early 19th-century livestock (and pigeon) breeders did in order to modify and improve their breeds.

The first chapter of the Origin is entitled, "Variation Under Domestication." He begins with "unnatural" selection and analogizes to the natural case.

Onto the rest:

We are doing what any species does: Overpopulating the world, trying to arrange things to suit us and polluting our environment.

Thus the "selection pressure"-- the collected set of criteria determining who lives and breeds and who dies-- are changing in the regular way for our species. We have, however, stalled our own evolution to a great extent: Many of the things that would have killed animals or even pre-historic people don't keep us from reproducing.

mvp
Apr. 8, 2012, 07:49 PM
What if the Hokey Pokey is really what it's all about?

If this is code for "have as much sex as you can and raise as many of those spawn to reproductive age as you can" then, yes, the Hokey Pokey IS what it's all about.

And there's a reason this sounds like a dirty and grand-parently term: The "fitness" of any one organism is not decided until it has grandbabies on the ground.

MunchingonHay
Apr. 8, 2012, 07:50 PM
Do you think people without their wisdom teeth (never came in) are more evolved than people that had their wisdom teeth?

Also, do you think that people that have smaller chin/jaws are more advanced than people with a more pronounced chin/jaw.

if that is the case, do you think that images of aliens with the big heads and no chin to little tiny chin are actually humans that have figured out space travel?




PS. I am an undergrad studying cultural anthro.

catalytic
Apr. 8, 2012, 07:54 PM
But...don't things actually devolve? Like take for instance the English language, society, the United States of America....if humans actually "evolved", wouldn't we be shooting light out of our unicorns or something by now? We haven't evolved since our creation.

mvp
Apr. 8, 2012, 07:59 PM
You forgot inserting genes from one species into another.;)

"Natural selection" is not a constant.

We didn't know genes are not immutable until not so long ago.
Many of them can be altered by the environment too, to the surprise of many.

There is more to this than straightforward changes.

Yes, ma'am! We haven't even scratched the surface of biology's weirdness. I was trying to get only as wacky as people could stand.

1) I did not forget "horizontal gene transfer" (within one species-- usually viruses) and between species (as in some weird, recently discovered sea slugs with chlorophyll and genes for it).
The notion of genetic transfers across species lines really screws up a lot of evolutionary theory based on zoology. Botanists? Meh, they have had to contend with this for a long time. Some plants can get jiggy with members of different genera.

2) No ma'am, Natural Selection is "not a constant." It's even worse than that if we *did* think it was always in play as evolutionists do.

See, N.S, is not a unified, culling kind of agent at all. It is the sum total of all things that kill an organism anywhere between generations. Chromosomes don't line up? Still born? A fine child but too crazy to find a mate? A fertile momma who eats all 7 of her kids while they are still tender and juicy? Great mom to 7 kids but they all stay celebate? No fitness for you!

Or, N. S. kills whole species and even higher taxa.

You are hot and having lots of babies. Your species is hot-- big and growing. Oops! Nuclear holocaust wipes you all out. No fitness for you!

Your species dies... and so does everything else that's not a cockroach or Stubben Seigfried? By definition, that whole wide swath of varied organisms becomes "unfit" no matter what came before.

So N.S. is hard to attribute except in retrospect. We just don't have good grammer for describing N.S. as a cause that keeps its indescribability at the fore. Also, it would look like a very bad, very untestable theory if you said "N.S. is at work always... and we can't see what it does." But Chuck knew that we couldn't fathom nature's sorting criteria. He says as much in the Origin.

3) And yes, our theory of the gene is changing.

FYI, we are about 100 years behind schedule with figuring this out.

That great deal to do with the defense of a strict form of Darwinism from about 1880 to 1930 or so. No Neo-Lamarckism, thank you very much. The idea that inheritance might respond to environmental stimulus and help adapt organisms and future generations was a problem: No one could give a physiological explanation for that. And N.S. might be a redundant theory if inheritance did all the work. There were some huge and very elegant fights about this in the 1890s.

mvp
Apr. 8, 2012, 08:17 PM
Do you think people without their wisdom teeth (never came in) are more evolved than people that had their wisdom teeth?

Also, do you think that people that have smaller chin/jaws are more advanced than people with a more pronounced chin/jaw.

if that is the case, do you think that images of aliens with the big heads and no chin to little tiny chin are actually humans that have figured out space travel?




PS. I am an undergrad studying cultural anthro.

No to the wisdom teeth question. Since impacted wisdom teeth don't kill people (now, and usually) there's no reason to think that "selection pressure" caused their loss.

Find a huge number of people refusing sex, citing "a tooth ache"? Then you're in business for your evolutionary story.

On "progress"-- Beware the idea! For two reasons:

1) The "goodness" of any feature or organism is quite relative to its circumstances. The tendency to sort good from bad in human features and races is an old and nefarious one-- as you well know, you cultural anthropologist, you.

2) And it's also hard to talk about bits of morphology as selected for or against. Things like teeth and chins have very different genetic and developmental causes. Not all of them have a "clean" relationship to natural selection built into the mythology of a Mendelian gene.

3) Jesus, I have know idea why we draw space aliens as we do. But see "pedomorphosis"-- the tendency for juvenile forms (think big heads and eyes like babies and Bambi). According to some, we like those proportions. Why not make aliens into pretty things?

PS-- chins have been discussed. They are not a "feature" subject to selection, per se. They are the result of the way our jaw bones (and those of our ancestors) fit together.

mvp
Apr. 8, 2012, 08:24 PM
But...don't things actually devolve? Like take for instance the English language, society, the United States of America....if humans actually "evolved", wouldn't we be shooting light out of our unicorns or something by now? We haven't evolved since our creation.

Yeah... but see above with my destruction of the notion of "progress" in any accurate description of evolution. Things don't get better in an absolute sense. Evolution makes them "as good as need be" for the particular circumstances of the organism. Good, deathly bad, and "good enough" are relative terms.

I'm not convinced that we should be comparing natural evolution to culture.... Of course, the people who think evolution is a great bit of science are IN culture... it's hard to untangle.

So the answers to your questions are:

1) No. No neither we, our language nor our society are "de-volving." You are correct, however, that we can evolve to some future state that will look like a previous one. It won't be exactly because time goes in only one direction.

2) If humans had the genes for horns... and any horned organism could shoot light out of those... and getting dates depended on it, then sure, we could evolve to be light-shooting unicorns.

Bluey
Apr. 8, 2012, 08:25 PM
If this is code for "have as much sex as you can and raise as many of those spawn to reproductive age as you can" then, yes, the Hokey Pokey IS what it's all about.

And there's a reason this sounds like a dirty and grand-parently term: The "fitness" of any one organism is not decided until it has grandbabies on the ground.

There are some theories of why human knowledge is advancing so much faster that it did before, that we have the mass to do so.
The more people out there, the more individuals that will be working on any one problem and so we get results sooner.

To have "too many humans" is a disadvantage when it comes to distributing resources, or worse, fighting over them, but it gives us also more people to keep working on solving problems, including those that do bring us better uses of resources.

No one knows where we are going or how the future will look, but it has been and maybe still will be for a while longer a terrific run for our species.:cool:

FlightCheck
Apr. 8, 2012, 08:34 PM
I am so enjoying this thread

catalytic
Apr. 8, 2012, 08:44 PM
What do you think of this video?

http://www.youtube.com/watch?v=w7qZnieFvNs&feature=relmfu

I'm seriously curious because to me it only makes sense because I believe in the Nephilim in the Bible. In a geology sense, it seems totally impossible because of the way granite is created. (unless they mis-catagorized the rock)

catalytic
Apr. 8, 2012, 08:46 PM
No one knows where we are going or how the future will look, but it has been and maybe still will be for a while longer a terrific run for our species.:cool:

Actually some of us do, the Bible is full of prophecy and I've read most of Revelation;)

mswillie
Apr. 8, 2012, 08:49 PM
Also, we have a cool feature: The sutures in the human skull and come unglued for a sec. and allow those plates to slide over one another in the birth canal.



Most of the time. However once in a while they don't. :no: Without medical intervention my son and I both likely would have been removed from the gene pool.

As it stands we both survived and he just had a son. Am I fit or a fluke? ;)

mvp
Apr. 8, 2012, 08:57 PM
What do you think of this video?

http://www.youtube.com/watch?v=w7qZnieFvNs&feature=relmfu

I'm seriously curious because to me it only makes sense because I believe in the Nephilim in the Bible. In a geology sense, it seems totally impossible because of the way granite is created. (unless they mis-catagorized the rock)


As with much of paleontology, you need to look for circumstantial evidence that confirms or disconfirms the theory.

Or you can believe what Biblical lore-- still a preponderence of text there-- says.

So, which is the most likely theory:

1) A 21' tall hominid made this imprint... in granite
2) Someone carved it just to mess with us. It was found in 1912. "Piltdown man" (a hoax) was of the same era. It could have been faked.
3) The Bible speaks of past giant humans... and explains enough of what people looking to nature for confirmation of all of it's claims say that you buy this account.

But the thing could be studied with more precision. Have they worked out the "how granite is formed-- it's not like stones that came from mud" problem? Have they dated the rock and correlated that with known species roving at the time? Any evidence of a hominid this large anywhere anytime? Did they do the scaling right to estimate the thing's whole size? Would a walking organisms of that size/weight left that kind of impression on the soft substrate (mud?)

mvp
Apr. 8, 2012, 09:03 PM
Most of the time. However once in a while they don't. :no: Without medical intervention my son and I both likely would have been removed from the gene pool.

As it stands we both survived and he just had a son. Am I fit or a fluke? ;)

By definition, grandma, you are fit. I don't care if you had to drag your man to bed by the hair and then personally slay lions to feed your young. You achieved granny status, so you are fit.

What, exactly, made you fit?

It could be a pair of foreceps or a C-section or the invention of health insurance or the existence of free medical care for the indigent. If those were "not yours" but another person's invention, that of your society or species, then *that's* the locus of your fitness. You got fitness by virtue of your membership in either of those things.

This means that selection can sort on all kinds of "levels" of organization-- from single genes (though rarely), to chromosomes, to families, to societies, species and higher taxa.

CR Gorge Girl
Apr. 8, 2012, 10:09 PM
But...don't things actually devolve? Like take for instance the English language, society, the United States of America....if humans actually "evolved", wouldn't we be shooting light out of our unicorns or something by now? We haven't evolved since our creation.

Since evolution is defined as the change in allele frequencies in a population, what about human populations in Africa that have a higher frequency for being carriers of sickle cell, because it's selected FOR in that case (you don't get malaria, and you don't die from sickle cell anemia), vs the European population that has a lower frequency of that allele.

Or another population where too much inbreeding occurred, and the alleles for (oh crap.. something to do with their hands--deformity-) became fixed in the population.

Plus the fastest that speciation has ever occurred is 14,000 years (for what I can't remember right now), and 36,000 years for Drosophila (fruit flies) in Hawaii.

MVP is that correct? Is that technically evolution?

Shiaway
Apr. 8, 2012, 10:17 PM
I'd like to add a little to what MVP has said. I'm getting my masters in molecular biology but my thesis is about evolutionary genomics. Not an expert by any stretch but I am interested in this stuff.

Someone asked about why species become more complex and not simpler. I would use a mathematical argument for this. There is a physical law that says everything tends towards entropy (chaos) but you can also think of entropy as just more information. It's like when you die your body decays it goes towards entropy. I would contend (right word?)that this is also part of the reason, if you think about genes and how they evolve, for the evolution of more complex species.

What it really boils down to (and no one is going to like this answer, especially people who believe in god or a higher purpose) is what is best for our genes. Essentially we are just hosts that our genes have made to best replicate themselves. Or to put it more eloquently I'll steel from my PI "life is what the genome surrounds itself with to survive". And this comes down again to math, because if something can replicate itself and something else can't, than the thing that will be around longer is the thing that can replicate itself. It almost seem, in that sense that life is inevitable, given enough time and material.

Someone else asked if only cockroaches and stubbens around be around after a nuclear holocaust. That is incorrect. Nematodes will be around I am sure of it. Nematodes (round worms--not just the kind you find in your horse, many are soil dwellers) are the most abundant multiorganism on the planet. I personally think they are the ultimate survival machine. You can starve them and they simply go into a stasis of a sort and can extend their life span by 3X or there abouts. You can freeze them in liquid nitrogen. You can even bleach them for a good 5 minutes and their eggs will survive. The only thing they don't like is dry heat but I'm sure given, that they make up 80% of the ocean floor they would have no trouble surviving a holocaust.

Someone else asked about why parasites kill their hosts. MVP already answered this but I just wanted to add to his answer. I will put on my population genetics hat and pretend to know what I'm talking about. ^_^ When talking about disease and I wouldn't be surprised if this applies to parasites as well, when you have a large host population you will find that a disease can afford to be much more virulent because there is always another host. With a smaller population the disease can't afford to be as severe. I probably did not explain that very well but hopefully you get the idea.

spotted mustang
Apr. 8, 2012, 10:21 PM
if men and women both belong to the same species, why are women so much higher evolved?

Fred
Apr. 8, 2012, 10:25 PM
Yes.

Count on it. Bet on it. Too bad you won't be there. Too bad currency won't exist any more. But if you can find some post-Apocalypse endzone to do a dance in, I suggest you get nekkid and let 'er rip.

Celebrate your having been right because you'll die of radiation sickness or starvation or heinous mano-a-mano fighting with your species surrounded by toilet seat saddles and bugs.

...and Volvos
..and Keith Richards

I'm loving this thread.

mvp
Apr. 8, 2012, 10:43 PM
Finally! We get to the genetic definition of evolution...And we are into the first half of the 20th-century, folks.


Since evolution is defined as the change in allele frequencies in a population, what about human populations in Africa that have a higher frequency for being carriers of sickle cell, because it's selected FOR in that case (you don't get malaria, and you don't die from sickle cell anemia), vs the European population that has a lower frequency of that allele.

Or another population where too much inbreeding occurred, and the alleles for (oh crap.. something to do with their hands--deformity-) became fixed in the population.

Plus the fastest that speciation has ever occurred is 14,000 years (for what I can't remember right now), and 36,000 years for Drosophila (fruit flies) in Hawaii.

MVP is that correct? Is that technically evolution?

A primer for the rest of yas, first:

We credit Gregor Mendel with supplying a "particulate theory of inheritance" that will work with natural selection. By 1909, these stable units transmitted between generations were named "genes."

An allele is one form of a gene. There can be two or more of these. They are part of the "classical theory of the gene"-- the one you learned. The "allele" talk still works, but genes-- yes, they are DNA, yes they are on chromosomes-- are now being redefined with respect to bits of morphology. No 1:1 correlation any more as Mendel ASSumed in order to get his (1865) experiments off the ground.

This "redefinition of the gene" going on now is especially true and important for evolutionists BECAUSE genetic theories of evolution treat the relationship between mutations to genes (an allele changing from one form to another) and the culling effects of natural selection.

More history: During the 1920s and 1930s, three math-heads, British statistician, R. A. Fisher, American physiological geneticist (dude who studies genes' expression during development), Sewall Wright, and J. B. S. Haldane (a jack-of-all-trades promoter of genetic theory and research) established Theoretical Population Genetics.

The goal of Theoretical Population Genetics was a phat one: To mathematically represent the process of evolution, and then to write equations that would tell you what would happen in different scenarios involving rates of mutation and intensity of selection.

Most of all, Fisher, Haldane and Wright wanted to show that Darwinian selection could work: The goal was to demonstrate that very little selection pressure (selection doesn't kill all of the organisms holding a given allele) and low mutation rate as is found in nature (new forms of a gene don't pop up often) would nevertheless produce directional and sustained change. This would kick all non-Darwinian theories to the curb.

Back to the question:

So "change in allele frequency" becomes the sign of evolution in this math and talk. Change in allele frequency means "The proportion of individuals in a population holding one allele as opposed to another." Presumably, selection was the force that created that proportion because genetic mutation is random with respect to selection pressure.

Because genes mutate in "all directions"-- toward the one that selection will preserve in a population over time and also toward the "bad" allele, you can see that selection will be more effective in a large population over time and small (or inbred) populations are SOL.

Big populations (and those with the right breeding structure) "hold" lots of variation-- lots of the alleles not currently favored. They can tolerate change in selection pressure.

Little or inbred populations are SOL: They *can't* respond to selection pressure because mutation rates are low. In other words, if a mutation normally occurs, say, once per every 10,000 generations, the population with just 1,000 individuals in it will have to wait (with the wrong allele) longer than will, say, a population with 100,000 members.

It gets more complex than if you consider genes' relationship to one another during development and therefore in their relationship to selection. But you get the basic mathematical system.

So!

1) Malaria is a famous example in which a key trait for survival has a single gene as its cause and just two alleles involved, IIRC. The heterozygous condition (one of each allele in individuals) is favored. It's not that these folks don't get malaria, it's that only some of the red blood cells will sickle in low oxygen environments for those individuals possessing both alleles. Given the prevalence of malaria in Africa (everywhere and for a very long time), no one will avoid it. But better to suffer with malaria than die from it before reproductive age. Thus, the allele that is deleterious in it's homozygous form gets preserved in the population.

In Europe, on the other hand, we can assume that the mutation did not show up. If it did there would be no benefit there to either the homozygous or heterozygous condition. Thus, the same allele would be lost (though slowly) in that population.

I'm not sure I have this malaria stuff right. I am sure I have the basic population genetics right. Take what you like....

2) Polydactyly in inbred populations. Whether it is caused by one gene or a suite of them traveling together on a small section of a chromosome, it's a math problem: Should that feature show up, it's original owners allowed to reproduce AND the population is small/inbred, the feature will stay.

3) Rates of speciation. A lot of handwaving here, folks. It's very, very hard to get a genetic description of a natural population or a species. Don't buy the hype too easily.

The hype-- particularly about wild species of Drosophila was sold to you by Theodosius Dobzhansky (a truly great scientist who worked with Wright on this stuff for 40 years), and Ernst Mayr. Mayr was another great intensely interested in developing a theory of speciation. The man did not read the math, FYI. We are now in the second half of the 20th century.

How fast does one species become another? Umm... if we are speaking in genetic terms, I'll have to insist that it's hard to measure. If we look at other ideas and data (Cichlid fish in Lake Victoria in Africa) we are looking at speciation rates that are much faster. The lakes themselves are only 12,000 years old. The number of species (and are they species?) is huge. But most people think it's hard to pin a "how many years" number for speciation.

Shiaway
Apr. 8, 2012, 10:44 PM
if men and women both belong to the same species, why are women so much higher evolved?


I get you were joking although I usually don't find this sort of joke funny. But anyway, if you look at the concept of males in terms of evolution, they are almost like parasites (sorry guys!) first there were female organisms (definition of female being the one who lays the eggs) and then the male almost piggy-backs in a sense. He gets to pass on his genes but doesn't have to do the work. That's a bit simplistic because males do contribute. They contribute by adding variation which can be a very good thing (and sometimes a bad thing--there are always trade offs*more later) and they can also serve to protect/help raise the young and ensure the genes continue on.

Speaking of variation and trade-offs. I know every generally thinks in-breeding is a very bad thing and very unhealthy, however there are some important benefits to in-breeding. I believe they have found that many wild horse populations are quite in-bred. The benefit of this is the whole "don't fix it if it ain't broke". By that I mean, when you have a good thing, it's working well the best way to ensure your offspring inherit those traits is to mate with someone who shares those same traits. The trade off of course is there's more risk of recessive lethals but also if the environment/selective pressure changes fewer of your off spring are likely to survive.

For example, if a disease comes through and you have some trait that makes your immune system unable to defeat the disease, and your progeny is the result of inbreeding, most likely (depending on how in-bred) your progeny will have the same immune system and also die. However, if there was no as much in-breeding there's a better chance some will survive the disease.

Shiaway
Apr. 8, 2012, 10:48 PM
Also to MVP,
I wish evolutionary biologists wouldn't ignore introns the way they do. But I guess until more research shows their importance in the evolution of a gene and of the genome, they will continued to be mostly ignored.

BlueEyedSorrel
Apr. 8, 2012, 10:57 PM
Love this thread! I'm an immunology PhD whose thesis had a heavy emphasis on genomics.


Also to MVP,
I wish evolutionary biologists wouldn't ignore introns the way they do. But I guess until more research shows their importance in the evolution of a gene and of the genome, they will continued to be mostly ignored.

Agreed. People tend to ignore what they don't understand.

As I recall, the mutation in the IGF1 gene which is associated with small size in dogs is within an intron.

BES

rustbreeches
Apr. 8, 2012, 11:04 PM
My science vocabulary failed me right around cockroaches, but by golly, I am really liking this thread!

mvp
Apr. 8, 2012, 11:10 PM
I'd like to add a little to what MVP has said. I'm getting my masters in molecular biology but my thesis is about evolutionary genomics. Not an expert by any stretch but I am interested in this stuff.

Someone asked about why species become more complex and not simpler. I would use a mathematical argument for this. There is a physical law that says everything tends towards entropy (chaos) but you can also think of entropy as just more information. It's like when you die your body decays it goes towards entropy. I would contend (right word?)that this is also part of the reason, if you think about genes and how they evolve, for the evolution of more complex species.

What it really boils down to (and no one is going to like this answer, especially people who believe in god or a higher purpose) is what is best for our genes. Essentially we are just hosts that our genes have made to best replicate themselves. Or to put it more eloquently I'll steel from my PI "life is what the genome surrounds itself with to survive". And this comes down again to math, because if something can replicate itself and something else can't, than the thing that will be around longer is the thing that can replicate itself. It almost seem, in that sense that life is inevitable, given enough time and material.

Someone else asked if only cockroaches and stubbens around be around after a nuclear holocaust. That is incorrect. Nematodes will be around I am sure of it. Nematodes (round worms--not just the kind you find in your horse, many are soil dwellers) are the most abundant multiorganism on the planet. I personally think they are the ultimate survival machine. You can starve them and they simply go into a stasis of a sort and can extend their life span by 3X or there abouts. You can freeze them in liquid nitrogen. You can even bleach them for a good 5 minutes and their eggs will survive. The only thing they don't like is dry heat but I'm sure given, that they make up 80% of the ocean floor they would have no trouble surviving a holocaust.

Someone else asked about why parasites kill their hosts. MVP already answered this but I just wanted to add to his answer. I will put on my population genetics hat and pretend to know what I'm talking about. ^_^ When talking about disease and I wouldn't be surprised if this applies to parasites as well, when you have a large host population you will find that a disease can afford to be much more virulent because there is always another host. With a smaller population the disease can't afford to be as severe. I probably did not explain that very well but hopefully you get the idea.

So... we'll have bugs, fugly saddles and worms after the nuclear holocaust. Super great. I'm not stayin'.

The population genetics stuff (see above) was put into forms that biologists in all fields could understand during the "Evolutionary Synthesis"-- roughly 1937-1953. IMO, it has become *the* modern restatement of Darwin's idea.

Because that math represents natural selection as a force, we get in the habit of talking about selection that way (again). Because the math also represents "evolution" in terms of alleles becoming more or less common in a population, we are invited to think about genes (properly: alleles) as competing for passage to the next generation.

Shiaway is correct in talking about virus' having "strategies" that work in larger and smaller host populations or genes that make organisms do this and that.

But beware the metaphors! Selection doesn't pluck single allele out of organisms and judge it. It kills or preserves the whole shebang-- that's lots of alleles, their interactions (maybe some responsive genes, maybe some epigenetic things). And selection might also be favoring some quality of the species. Yeah, some allele in some individual is going along for the ride from generation to generation. But it would be very, very tough to say "this allele is responsible for the species-wide property of, say, polymorphic coloring."

mvp
Apr. 8, 2012, 11:15 PM
if men and women both belong to the same species, why are women so much higher evolved?


Meh, see above. There is real risk--of bad politics and unprovable science-- in talking about "higher and lower" with things evolutionary.

Don't believe me? How about the fact that the AIDS virus will kill any of us. It's small. It's not "alive" by common definitions of life. It won't come out and fight like a man. It's dirt simple.

Funny thing about men and women, and evolutionary theory. Some can't decide what or who does the selecting. In many theories of sexual selection, the women are the arbiters of reproduction at the end.

And then, really, all sexually-reproducing species need to do is be good enough to get it on with each other. Men can be heinous. Women can be heinous. Check out the child-ed couples on Jerry Springer and try to tell me that natural selection has high standards.

mvp
Apr. 8, 2012, 11:20 PM
Also to MVP,
I wish evolutionary biologists wouldn't ignore introns the way they do. But I guess until more research shows their importance in the evolution of a gene and of the genome, they will continued to be mostly ignored.

Me, too. They should care about frame shifts. They should care about the amazing and unpredicted weirdness of DNA that repeats often. They should care about how we decided what was "genetic" and what was "epigenetic". They should have thought about different classes of genes a long time ago. Regulatory and structural genes didn't need to be such a recent distinction. They should hurry up and try to establish the evolutionary origins (dates and phylogenetic branching points) for old, conserved genes.

Since I just sit in the easy chair of the historian, I'll just take all of 20th-century biology to task for picking an evolutionary theory before they had more than a "meh...works good enough" theory of inheritance and development.

CR Gorge Girl
Apr. 8, 2012, 11:22 PM
Finally! We get to the genetic definition of evolution...And we are into the first half of the 20th-century, folks.



A primer for the rest of yas, first:

We credit Gregor Mendel with supplying a "particulate theory of inheritance" that will work with natural selection. By 1909, these stable units transmitted between generations were named "genes."

An allele is one form of a gene. There can be two or more of these. They are part of the "classical theory of the gene"-- the one you learned. The "allele" talk still works, but genes-- yes, they are DNA, yes they are on chromosomes-- are now being redefined with respect to bits of morphology. No 1:1 correlation any more as Mendel ASSumed in order to get his (1865) experiments off the ground.

This "redefinition of the gene" going on now is especially true and important for evolutionists BECAUSE genetic theories of evolution treat the relationship between mutations to genes (an allele changing from one form to another) and the culling effects of natural selection.

More history: During the 1920s and 1930s, three math-heads, British statistician, R. A. Fisher, American physiological geneticist (dude who studies genes' expression during development), Sewall Wright, and J. B. S. Haldane (a jack-of-all-trades promoter of genetic theory and research) established Theoretical Population Genetics.

The goal of Theoretical Population Genetics was a phat one: To mathematically represent the process of evolution, and then to write equations that would tell you what would happen in different scenarios involving rates of mutation and intensity of selection.

Most of all, Fisher, Haldane and Wright wanted to show that Darwinian selection could work: The goal was to demonstrate that very little selection pressure (selection doesn't kill all of the organisms holding a given allele) and low mutation rate as is found in nature (new forms of a gene don't pop up often) would nevertheless produce directional and sustained change. This would kick all non-Darwinian theories to the curb.

Back to the question:

So "change in allele frequency" becomes the sign of evolution in this math and talk. Change in allele frequency means "The proportion of individuals in a population holding one allele as opposed to another." Presumably, selection was the force that created that proportion because genetic mutation is random with respect to selection pressure.

Because genes mutate in "all directions"-- toward the one that selection will preserve in a population over time and also toward the "bad" allele, you can see that selection will be more effective in a large population over time and small (or inbred) populations are SOL.

Big populations (and those with the right breeding structure) "hold" lots of variation-- lots of the alleles not currently favored. They can tolerate change in selection pressure.

Little or inbred populations are SOL: They *can't* respond to selection pressure because mutation rates are low. In other words, if a mutation normally occurs, say, once per every 10,000 generations, the population with just 1,000 individuals in it will have to wait (with the wrong allele) longer than will, say, a population with 100,000 members.

It gets more complex than if you consider genes' relationship to one another during development and therefore in their relationship to selection. But you get the basic mathematical system.

So!

1) Malaria is a famous example in which a key trait for survival has a single gene as its cause and just two alleles involved, IIRC. The heterozygous condition (one of each allele in individuals) is favored. It's not that these folks don't get malaria, it's that only some of the red blood cells will sickle in low oxygen environments for those individuals possessing both alleles. Given the prevalence of malaria in Africa (everywhere and for a very long time), no one will avoid it. But better to suffer with malaria than die from it before reproductive age. Thus, the allele that is deleterious in it's homozygous form gets preserved in the population.

In Europe, on the other hand, we can assume that the mutation did not show up. If it did there would be no benefit there to either the homozygous or heterozygous condition. Thus, the same allele would be lost (though slowly) in that population.

I'm not sure I have this malaria stuff right. I am sure I have the basic population genetics right. Take what you like....

2) Polydactyly in inbred populations. Whether it is caused by one gene or a suite of them traveling together on a small section of a chromosome, it's a math problem: Should that feature show up, it's original owners allowed to reproduce AND the population is small/inbred, the feature will stay.

3) Rates of speciation. A lot of handwaving here, folks. It's very, very hard to get a genetic description of a natural population or a species. Don't buy the hype too easily.

The hype-- particularly about wild species of Drosophila was sold to you by Theodosius Dobzhansky (a truly great scientist who worked with Wright on this stuff for 40 years), and Ernst Mayr. Mayr was another great intensely interested in developing a theory of speciation. The man did not read the math, FYI. We are now in the second half of the 20th century.

How fast does one species become another? Umm... if we are speaking in genetic terms, I'll have to insist that it's hard to measure. If we look at other ideas and data (Cichlid fish in Lake Victoria in Africa) we are looking at speciation rates that are much faster. The lakes themselves are only 12,000 years old. The number of species (and are they species?) is huge. But most people think it's hard to pin a "how many years" number for speciation.


Well, since the fish never come into contact with each other naturally, therefore never interbreed, they are separate species. Eastern and Western meadowlarks are almost identical, but since they don't recognize each others mating calls, they never interbreed, and therefore, are separate species.

and lol, you're pretty much saying the same things as my genetics prof, the textbook lays it out all pretty, but really it's not. Mendel got extremely lucky that the traits he chose to study were located on different chromosomes, and weren't linked to any other--no epistasis, no polygenic inheritance.

mvp
Apr. 8, 2012, 11:24 PM
...and Volvos
..and Keith Richards

I'm loving this thread.

'K, post-human extinction we'll still have:

Cockroaches
Stubben Seigfried saddles
Nematodes
Volvos
Keith Richards... who will be lonely and really horny... and if he is lucky, the founding male of the next human species.

Have a nice day.

mvp
Apr. 8, 2012, 11:27 PM
Well, since the fish never come into contact with each other naturally, therefore never interbreed, they are separate species. Eastern and Western meadowlarks are almost identical, but since they don't recognize each others mating calls, they never interbreed, and therefore, are separate species.

and lol, you're pretty much saying the same things as my genetics prof, the textbook lays it out all pretty, but really it's not. Mendel got extremely lucky that the traits he chose to study were located on different chromosomes, and weren't linked to any other--no epistasis, no polygenic inheritance.

Then you know that there are many, many species definitions out there.

I think Mendel chose the traits he did because they were on separate chromosomes and obvious. That's how you reliably get independent assortment.

On to the trick question, then: How do evolutionists know when selection is choosing an allele versus a bunch of genes linked in development versus a section of chromosome? I think it's an enormous problem built into Sewall Wright's fitness surfaces/adaptive landscape. Those are some incredibly influential diagrams in modern evolutionary biology. They have been assigned several different meanings...and few realize it.

fargaloo
Apr. 8, 2012, 11:42 PM
Fun thread - my PhD is in evolutionary biology, but I have kind of drifted into community ecology of late....

One thing I'd like to add is that modern humans are experiencing very weak levels of natural selection as there is almost no correlation between genetic fitness (who survives and contributes alleles to the next generation) and genotype. Natural selection may kick in if we experience some kind of catastrophe that will lead to the collapse of modern medicine and technologies, but till then we are getting a free ride.

I agree - introns will be where it's at for the next while.... and all the rest of the "junk" DNA!

Here is a cool article on introns for anyone interested: http://www.sciencedaily.com/releases/2011/11/111129112329.htm

mvp
Apr. 8, 2012, 11:52 PM
Fun thread - my PhD is in evolutionary biology, but I have kind of drifted into community ecology of late....

One thing I'd like to add is that modern humans are experiencing very weak levels of natural selection as there is almost no correlation between genetic fitness (who survives and contributes alleles to the next generation) and genotype. Natural selection may kick in if we experience some kind of catastrophe that will lead to the collapse of modern medicine and technologies, but till then we are getting a free ride.

I agree - introns will be where it's at for the next while.... and all the rest of the "junk" DNA!


Ooh. Community ecology. So are you a fan of Niche Construction Theory? I can't decide if it says anything new or not.

And on weak selection for us: Are you saying that the correlation between single alleles and our whole genotype is limited? I'd expect that to be true for most alleles in most species most of the time.

Or do you mean a weak correlation between genetic fitness and phenotype....and those features "visible" to selection but not really killing anyone off?

alterhorse
Apr. 8, 2012, 11:54 PM
Are there any predictable trends about evolution that might be used to form a computer model that might simulate a statistical probability of how people may change, and what they will become like in the distant future?

In other words can evolutionary science be use to predict future changes in living creatures?

Leave the environmental factors of weather, vegetation, and fauna exactly as they are now if it helps to simplify the modeling.

fargaloo
Apr. 9, 2012, 12:05 AM
Yes, very true - I am talking about the correlation between fitness and phenotype. Selection on single alleles is pretty low, as you point out (thank goodness as they often prove to be useful down the road.... as species experiencing drift discover to their peril!)

I am not a huge fan of NCT - not that I don't acknowledge that it is true, but I think it's old wine in new bottles...it probably helps in modeling to explicitly build in feedback loops but I'm not a modeler these days ;)

Bluey
Apr. 9, 2012, 12:06 AM
Fun thread - my PhD is in evolutionary biology, but I have kind of drifted into community ecology of late....

One thing I'd like to add is that modern humans are experiencing very weak levels of natural selection as there is almost no correlation between genetic fitness (who survives and contributes alleles to the next generation) and genotype. Natural selection may kick in if we experience some kind of catastrophe that will lead to the collapse of modern medicine and technologies, but till then we are getting a free ride.

I agree - introns will be where it's at for the next while.... and all the rest of the "junk" DNA!

Here is a cool article on introns for anyone interested: http://www.sciencedaily.com/releases/2011/11/111129112329.htm

I got a free ride.
Born right after WWII, I had pneumonia as a two year old, was very sick in the hospital and was one of the first in the general population to get that new miracle medicine, penicillin.;)

Sometimes, you get lucky and heck, that counts also in evolution.:)

Ponytoes
Apr. 9, 2012, 12:15 AM
:)
What if the Hokey Pokey is really what it's all about?

Ponytoes
Apr. 9, 2012, 12:20 AM
Its a Jimmy Buffett song..:lol:

mvp
Apr. 9, 2012, 12:48 AM
Are there any predictable trends about evolution that might be used to form a computer model that might simulate a statistical probability of how people may change, and what they will become like in the distant future?

In other words can evolutionary science be use to predict future changes in living creatures?

Leave the environmental factors of weather, vegetation, and fauna exactly as they are now if it helps to simplify the modeling.


Nope. No computer simulations. But a weird, fanciful picture book with a bunch of imagined options.

And yes, some biologists do try to predict changes in morphological form. It's fun and theoretical.

The best forms of this involve using "morphospace"-- and it works only for very limited kinds of features (shapes of shells, sometimes proportional ratios in dimensions of parts like skulls or bones). I think some people do it with plant shape.

First they need to do this developmentally-- talking about how genes (and the rest) produce the shapes they do. Then figuring in environment? I think you could do that for very well understood systems.

mvp
Apr. 9, 2012, 12:54 AM
Yes, very true - I am talking about the correlation between fitness and phenotype. Selection on single alleles is pretty low, as you point out (thank goodness as they often prove to be useful down the road.... as species experiencing drift discover to their peril!)

I am not a huge fan of NCT - not that I don't acknowledge that it is true, but I think it's old wine in new bottles...it probably helps in modeling to explicitly build in feedback loops but I'm not a modeler these days ;)

On Niche Construction Theory:

FYI: Mainly promoted by a very nice, old skool English guy, F. (?) John Odling-Smee since 2003 or so. He points out that organisms shape their environment, changing selection pressures for future generations and others. Think of beavers building dams.

Ecologists might have to care because while they usual think of "keystone species" or "trophic levels," these environmental engineers might really be the determiners of conditions.

Why do evolutionists have to care? Isn't community-engineering just one more element of "the environment" and selection pressure? I don't get it.

mvp
Apr. 9, 2012, 01:00 AM
I got a free ride.
Born right after WWII, I had pneumonia as a two year old, was very sick in the hospital and was one of the first in the general population to get that new miracle medicine, penicillin.;)

Sometimes, you get lucky and heck, that counts also in evolution.:)

You did *not* get lucky. There is no luck in evolution. There are only changing selection pressures.

You were part of a species that invents cool stuff like penicillin and gives it to little kids. If you personally did "get lucky" it was by being born in the time and place that you were.

And so, my friends, there are some legitimate reasons to think of some of the big, collective good kinds of things we produce as "adaptive."

Blugal
Apr. 9, 2012, 02:02 AM
Someone else on this thread brought up the idea that because we are doing so well as a species (at least, from a "taking over resources, reproducing, and edging out others" perspective), we also have greater numbers from which we can pluck great scientists, thinkers, etc. And from those, we may be able to come up with solutions to scarce resources/overpopulation problems.

I had not thought about it that way. I guess I had thought about it the way the movie Idiocracy portrays it (although I realize this is simplistic): tons of reproduction by the masses, very little reproduction by the highly educated/wealthy. Increased fighting over scarce resources.

What do you think?

Tom King
Apr. 9, 2012, 08:41 AM
Where did all the stuff come from that created the big bang?

It was condensed from the last cycle. Matter and energy are different states of the same stuff. After it all turns to energy, it passes the equilibrium point, and comes back together as matter, and when gravity pulls it all back together to the breaking point, it explodes and starts all over again. Our universe is probably not the only one.

alterhorse
Apr. 9, 2012, 09:11 AM
It was condensed from the last cycle. Matter and energy are different states of the same stuff. After it all turns to energy, it passes the equilibrium point, and comes back together as matter, and when gravity pulls it all back together to the breaking point, it explodes and starts all over again. Our universe is probably not the only one.

I like those sorts of mind boggling ideas.:yes:

Makes me envision multiple universes existing in a multiverse, and then multiple multiverses existing in a water drop clinging to the side of a stone next to a meandering woodland stream. ;)

BravAddict
Apr. 9, 2012, 09:31 AM
It was condensed from the last cycle. Matter and energy are different states of the same stuff. After it all turns to energy, it passes the equilibrium point, and comes back together as matter, and when gravity pulls it all back together to the breaking point, it explodes and starts all over again. Our universe is probably not the only one.

Mind blown.

fargaloo
Apr. 9, 2012, 09:53 AM
MVP - yes, that's my objection about niche construction theory as well. Ecologists have been explicitly concerned with feedback between organisms and environment really from the time of Lindeman onwards - the concept of a keystone species neatly encapsulated this. If NCT is means for developing an algorithm for looking at shifting selection coefficients in a landscape of selective pressures it adds something but it's not a new concept IMHO.

I have to respectfully disagree when you say there is no "luck" in evolution (but perhaps we are thinking of the terms in different ways). there is a great deal of luck or chance in determining which alleles make it to the next generation. Random events create variation, and random events remove alleles from the pool as well.


It was condensed from the last cycle. Matter and energy are different states of the same stuff. After it all turns to energy, it passes the equilibrium point, and comes back together as matter, and when gravity pulls it all back together to the breaking point, it explodes and starts all over again. Our universe is probably not the only one.

:D :D love this!!

Bluey
Apr. 9, 2012, 10:11 AM
It was condensed from the last cycle. Matter and energy are different states of the same stuff. After it all turns to energy, it passes the equilibrium point, and comes back together as matter, and when gravity pulls it all back together to the breaking point, it explodes and starts all over again. Our universe is probably not the only one.

Entropy.

alterhorse
Apr. 9, 2012, 10:19 AM
MVP - yes, that's my objection about niche construction theory as well. Ecologists have been explicitly concerned with feedback between organisms and environment really from the time of Lindeman onwards - the concept of a keystone species neatly encapsulated this. If NCT is means for developing an algorithm for looking at shifting selection coefficients in a landscape of selective pressures it adds something but it's not a new concept IMHO.

I have to respectfully disagree when you say there is no "luck" in evolution (but perhaps we are thinking of the terms in different ways). there is a great deal of luck or chance in determining which alleles make it to the next generation. Random events create variation, and random events remove alleles from the pool as well.


But then there's the concept that the nature of the universe is such that life becomes inevitable, and all the ideal forms for life to sequentially evolve through are just a microcosmic manifestation of the structure of the fabric of the universe itself.

The evolutionary scientist may only glimpse snapshots in the multitude of forms in which life may exist at any moment in time, but there may only be one viable outcome regardless of all of the possible pathways which evolution may take to achieve it.

The concept certainly does not negate the science, but it may be that the laws that govern the science, might actually be so extensive as to encompass the universe itself.

mvp
Apr. 9, 2012, 11:14 AM
Someone else on this thread brought up the idea that because we are doing so well as a species (at least, from a "taking over resources, reproducing, and edging out others" perspective), we also have greater numbers from which we can pluck great scientists, thinkers, etc. And from those, we may be able to come up with solutions to scarce resources/overpopulation problems.

I had not thought about it that way. I guess I had thought about it the way the movie Idiocracy portrays it (although I realize this is simplistic): tons of reproduction by the masses, very little reproduction by the highly educated/wealthy. Increased fighting over scarce resources.

What do you think?

I think Darwin was thinking about this.

Or rather, he borrowed a crucial idea from a guy who had: Thomas Malthus who wrote about the population problem in 1830s England.

That trend toward over-population (or so it looked to some elites on a small island nation) was/is the key thing that drives evolutionary competition. With enough for all, organisms can still be varied and it doesn't make a difference.

Which brings up a crucial point about this theory: It's made up by people to explain (among other things) people. Or rather, we more obviously seem to project our cultural ideas onto nature than in places like modern physics and chemistry.

Hence the fame and fights about evolutionary biology.

mvp
Apr. 9, 2012, 11:22 AM
And now off the deep end into philosophy of science.

It was the right place to go.


But then there's the concept that the nature of the universe is such that life becomes inevitable, and all the ideal forms for life to sequentially evolve through are just a microcosmic manifestation of the structure of the fabric of the universe itself.

The evolutionary scientist may only glimpse snapshots in the multitude of forms in which life may exist at any moment in time, but there may only be one viable outcome regardless of all of the possible pathways which evolution may take to achieve it.

The concept certainly does not negate the science, but it may be that the laws that govern the science, might actually be so extensive as to encompass the universe itself.


Darn tootin' on your discovery that the crap scientists make up about nature is both rigorous and utterly relative to our perspective.

Before you get to really big parts of evolutionary theory or philosophy of science in general, consider these more practical, modest problems:

1) A species who is the product of evolution made up the whole dang theory. How on Earth can you posit diddly about objectivity?

2) We have a lifespan of a given length-- way longer than bacteria, way shorter than that of a species. So..... how do we study even a lawful causal theory with time frames that put "the big stuff"-- the process of speciation and the process of adaptation--into terms way too long for us to observe?

3) And how do we study a historical natural process as opposed to things that work the same "in all places and all times"-- like physics and chemistry on Earth? What do y'all want to do about historical contingency in science in general? You can't have evolutionary biology if you whine that it's not like physics. If you do make it into something like physics, you may miss some kind of cause that was deeply influential in the history of evolution even though it only happened once.

wendy
Apr. 9, 2012, 11:32 AM
why, if things are constantly evolving why aren't there any "in between" stages,

there are- every single living thing you see is "in between" what once was and what will be.

alterhorse
Apr. 9, 2012, 12:23 PM
And now off the deep end into philosophy of science.

It was the right place to go.




Darn tootin' on your discovery that the crap scientists make up about nature is both rigorous and utterly relative to our perspective.

Before you get to really big parts of evolutionary theory or philosophy of science in general, consider these more practical, modest problems:

1) A species who is the product of evolution made up the whole dang theory. How on Earth can you posit diddly about objectivity?

2) We have a lifespan of a given length-- way longer than bacteria, way shorter than that of a species. So..... how do we study even a lawful causal theory with time frames that put "the big stuff"-- the process of speciation and the process of adaptation--into terms way too long for us to observe?

3) And how do we study a historical natural process as opposed to things that work the same "in all places and all times"-- like physics and chemistry on Earth? What do y'all want to do about historical contingency in science in general? You can't have evolutionary biology if you whine that it's not like physics. If you do make it into something like physics, you may miss some kind of cause that was deeply influential in the history of evolution even though it only happened once.

Incorporating concepts of social evolution can create a "division" between the corporeal and the incorporeal. With this idea we then acquire a perspective of knowledge as an independent object they may exist independent of life.

For example, one might send a vehicle into space containing the entire recorded body of knowledge of the human species. After the human species no longer exists, this body of knowledge may still exist independent of the life that created it.

Similarly the concept of science itself might then be thought of as a pre-existing environmental factor that has an evolutionary influence over the development of species.

Imagine what might happen on our planet if a space vehicle containing the body of knowledge of some long extinct alien race from another world, much more advanced then us, was to be discovered crash landed in Antarctica.

As we deciphered that alien knowledge, think of how in might impact both our own evolution, and the evolution of all life on our planet.

The point is that the science that we use to explain our world is simply a part of the overall evolution of our species, and the level at which that science is developed at any point in time, is both derived out of, and effectual over, our physical state of existence.

Science effectuates change, and change effectuates science.

The true mystery is the nature of the force that provides us with the drive to both, seek change, but also to resist it.

Science to is a process of seeking change, but also resisting it.

Thus science is a reflection of our physical nature, yet the knowledge that it generates can exist separately from our physical form, as a reflection of that form.

mvp
Apr. 9, 2012, 01:28 PM
I have to respectfully disagree when you say there is no "luck" in evolution (but perhaps we are thinking of the terms in different ways). there is a great deal of luck or chance in determining which alleles make it to the next generation. Random events create variation, and random events remove alleles from the pool as well.


Still way into the philosophy of science here-- now evolutionary biology versus physics (Newtonian, then Quantum (maybe), and chemistry.

At the very very bottom of the world-- Quantum whatnot-- we think things are indeterminate. They are stochastic-- a matter of statistical likelihood only.

Move "up a level" and you get to the very pretty and oh-so-determinate world of Newtonian mechanics.

Move up several more layers from that causal world of Newtonian mechanics to chemistry and biochemistry, and you DO get mutations that have appreciable causes.

Now move up a layer (or several) again-- to evolutionary biology-- and your question about *luck*.

Mutation are "random" with respect to selection pressure, aka with respect to the organism's adaptive need. But we don't know all of the stuff figures into that big Julius Ceaser "thumbs up, thumbs down" that N.S. gives any single organism on its day to live or die.

To call something "luck" (most non-Quantum types agree) is to acknowledge that we don't know all of the contributing and determinate causes.

ETA for you, Evolutionary Biology PhD: I'm not convinced that Sewall Wright's genetic drift actually happens... that's for some pretty decent technical reasons with his original 1931/1932 idea.

mvp
Apr. 9, 2012, 01:29 PM
there are- every single living thing you see is "in between" what once was and what will be.

If so, scientists are quite SOL. It would be impossible to generalize about anything.

mvp
Apr. 9, 2012, 01:35 PM
Incorporating concepts of social evolution can create a "division" between the corporeal and the incorporeal. With this idea we then acquire a perspective of knowledge as an independent object they may exist independent of life.

For example, one might send a vehicle into space containing the entire recorded body of knowledge of the human species. After the human species no longer exists, this body of knowledge may still exist independent of the life that created it.

Similarly the concept of science itself might then be thought of as a pre-existing environmental factor that has an evolutionary influence over the development of species.

Imagine what might happen on our planet if a space vehicle containing the body of knowledge of some long extinct alien race from another world, much more advanced then us, was to be discovered crash landed in Antarctica.

As we deciphered that alien knowledge, think of how in might impact both our own evolution, and the evolution of all life on our planet.

The point is that the science that we use to explain our world is simply a part of the overall evolution of our species, and the level at which that science is developed at any point in time, is both derived out of, and effectual over, our physical state of existence.

Science effectuates change, and change effectuates science.

The true mystery is the nature of the force that provides us with the drive to both, seek change, but also to resist it.

Science to is a process of seeking change, but also resisting it.

Thus science is a reflection of our physical nature, yet the knowledge that it generates can exist separately from our physical form, as a reflection of that form.


You have some astute observations in there. Good on 'ya!

My favorite part? You don't do the "Richard Dawkins move."

It has 2 parts:

1. All of evolution resolves into what happens to single genes. Bodies, societies, species-- those pups are pawns in the game.

2. Then "memes"-- cultural units analogous to competing and circulating genes-- do a parallel kind of work.

Awesome to say, stupid to take seriously, IMO.

No evolutionist who has thought about any of this hard at all things that there is a pure (and findable) relationship between single genes and selection. Heck, we have new questions about the relationship between genes and those traits of morphology or behavior that selection "sees." So if we don't know what a gene is for the purposes of talking about the thing that selection judges.... I think we should hold off on building too many analogies that rest on it.

WNT
Apr. 9, 2012, 01:36 PM
If so, scientists are quite SOL. It would be impossible to generalize about anything.

I think that is why many people can be intimidated by science, it is pretty much impossible to generalize!

alterhorse
Apr. 9, 2012, 03:06 PM
You have some astute observations in there. Good on 'ya!

My favorite part? You don't do the "Richard Dawkins move."

It has 2 parts:

1. All of evolution resolves into what happens to single genes. Bodies, societies, species-- those pups are pawns in the game.

2. Then "memes"-- cultural units analogous to competing and circulating genes-- do a parallel kind of work.

Awesome to say, stupid to take seriously, IMO.

No evolutionist who has thought about any of this hard at all things that there is a pure (and findable) relationship between single genes and selection. Heck, we have new questions about the relationship between genes and those traits of morphology or behavior that selection "sees." So if we don't know what a gene is for the purposes of talking about the thing that selection judges.... I think we should hold off on building too many analogies that rest on it.

Thanks for the ideas!

I think genes contain an overlapping capacity for redundancy that Darwin expressed in part as differentiation. Thus one shouldn't observe any single gene but rather the entire genome of a given species, and then look for the redundantly overlapping characteristics within that genome.

I think you will find multiple gene locations that are responsible to "similar" traits within the same species.

This is natures way of insuring that one fault won't destroy all the progress.

The information recorded in the genome is similarly separate from the DNA just as is the cultural information passed down through living memory form one generation to the next. The reason that this is true is because the DNA of any one single organism can not represent the "collective" contents of the entire genome of a species.

So the "knowledge" that the genome possesses is just as separate from the organism as the knowledge existing in any living memory an organism possesses.

These two factors then provide for a wide "continuum" of variations, and one might then realize that when these two components are mathematical multiplied together, the result is a level of capacity possessed by the organism that is directly equivalent to it's ability to adapt to a changing environment.

This is why humans are more adaptive then horses, because the human genome variation multiplied by the content of the human living memory and knowledge, equals something of a survival score, that is much greater then the result for the same computation done for a horse.

[Genome diversity] X [Living Memory/Knowledge] = [Adaptability/Capacity for Survival]

I just made that up by the way, so if no one has thought of it yet, I claim the right to name it. :D

spotted mustang
Apr. 9, 2012, 06:02 PM
But anyway, if you look at the concept of males in terms of evolution, they are almost like parasites (sorry guys!).

hehe. Gotta love those deep-sea anglerfishes, where the male is reduced to a tiny parasitic sperm dispenser permanently attached to the female's belly:

http://www.youtube.com/watch?v=Lsmxs0uDXMo

sunridge1
Apr. 9, 2012, 06:28 PM
hehe. Gotta love those deep-sea anglerfishes, where the male is reduced to a tiny parasitic sperm dispenser permanently attached to the female's belly:

http://www.youtube.com/watch?v=Lsmxs0uDXMo

Bwahahahah! I love it!

Donella
Apr. 9, 2012, 06:29 PM
I just tuned in and have two seconds before having to go to dinner but to one of the questions in the first part of the thread (if it has been answered sorry):

I am an atheist and a pro evolution person, however I have a question; why, if things are constantly evolving why aren't there any "in between" stages, do example, an ape in the in-between stage of the evolution to man. Sorry if this is a dumb question.

Because "pressure" acts not on every aspect of that being at one time, it acts on a very specific feature of an organism thus giving it better fitness ie color, arm length, a certain behaviour ect. That is why some features change drastically over time and some are preserved over millions of year.

Secondly, we do not "come from" apes, we share a common ancestor with them.

I can elaborate more when I have more time if need be.

Frizzle
Apr. 9, 2012, 09:40 PM
MVP, what do you think of this theory:

http://www.youtube.com/watch?v=CRBHxJBUv_A&sns=em

Sorry, couldn't resist! :lol:

fargaloo
Apr. 9, 2012, 09:54 PM
Mutation are "random" with respect to selection pressure, aka with respect to the organism's adaptive need. But we don't know all of the stuff figures into that big Julius Ceaser "thumbs up, thumbs down" that N.S. gives any single organism on its day to live or die.

To call something "luck" (most non-Quantum types agree) is to acknowledge that we don't know all of the contributing and determinate causes.

Yes, and that's what is relevant to the concept of luck or randomness in evolution - mutation and drift are random with respect to natural selection. And I agree that there are some deep questions at the heart of what is "random" or "chaotic" in a quantum universe, but I think that's a red herring in the discussion. An organism can fail to reach fitness due to it's phenotype (and ultimately genotype) but it also can fail to achieve genetic fitness because a big rock fell on its head -- so yes, I think there is randomness and "luck" in evolution.


ETA for you, Evolutionary Biology PhD: I'm not convinced that Sewall Wright's genetic drift actually happens... that's for some pretty decent technical reasons with his original 1931/1932 idea.

There has been debate about the IMPORTANCE of drift relative to selection (e.g. Fisher on one hand; Kimura on the other; Gillespie (draft vs. drift) raises criticisms about the mechanism)), but drift is a statistical fact....

fargaloo
Apr. 9, 2012, 10:12 PM
there are- every single living thing you see is "in between" what once was and what will be.
I don't see how this makes it "impossible to generalize" -- this is reality. Populations change at every generation, and what we think of as species are snapshots in time. The concept of a "chronospecies" is that there can be gradual changes (anagenesis) in a species over time (little changes accumulating over many, many generations) so that the original (ancestral) version is quite different from the descendant. If we saw two individuals -- one from the first generation, and one from a far later generation -- in the fossil record, we would probably think of them as belonging to separate species. New species also appear through cladogenesis, or splitting of an ancestral population into two different populations that start to follow their own evolutionary trajectory through time (like the example of the cichlid fishes mentioned previously.

alterhorse
Apr. 10, 2012, 12:05 AM
I don't see how this makes it "impossible to generalize" -- this is reality. Populations change at every generation, and what we think of as species are snapshots in time. The concept of a "chronospecies" is that there can be gradual changes (anagenesis) in a species over time (little changes accumulating over many, many generations) so that the original (ancestral) version is quite different from the descendant. If we saw two individuals -- one from the first generation, and one from a far later generation -- in the fossil record, we would probably think of them as belonging to separate species. New species also appear through cladogenesis, or splitting of an ancestral population into two different populations that start to follow their own evolutionary trajectory through time (like the example of the cichlid fishes mentioned previously.

I agree with the incremental approach during periods of slow environmental change, but I have another idea to explain what may happen during periods of rapid environmental change...

When any individual in any species becomes "too" unique, that individuals is either shunned by it's own kind, or stands out in the crowd and gets picked off by predators, and this "force" tends to keep the members of the species "similar".

But there is also a certain amount of evolutionary pressure that requires a level of diversity to allow for adaptation.

It's only when some environmental change makes the survival of a particular "form" impossible, that this "principle" that limits diversity "switches off", and allows a rapid change in form to occur. But once that change of form reaches the optimum state to survive in that new environment, the "limiting principle" switches back on again to optimize the potential for survival of that new form.

Mozart
Apr. 10, 2012, 12:11 AM
Best. Thread. Ever.

I am decidedly unscientific so I can only add the story of evolution according to my 10 yr old son (as told to me from the back seat of the car after I picked him up from daycare).

Me: "So..how was school? What did you learn"
Son: "Lots. Did you know we used to be fish?"
Me: "Well...I don't think we were fish, exactly"
Son: "Yes we were. First we were fish, then we were monkeys, then we were ugly hairy naked guys"

I know right now there are science teachers everywhere quietly weeping :lol:

fargaloo
Apr. 10, 2012, 12:36 AM
But there is also a certain amount of evolutionary pressure that requires a level of diversity to allow for adaptation.

It's only when some environmental change makes the survival of a particular "form" impossible, that this "principle" that limits diversity "switches off", and allows a rapid change in form to occur. But once that change of form reaches the optimum state to survive in that new environment, the "limiting principle" switches back on again to optimize the potential for survival of that new form.

Interesting. There was a fair bit of research a few years ago into the role of heat shock proteins (stress proteins in general) in rapid evolutionary change. HSPs are proteins that are expressed mostly when the organism is stressed (for example, exposed to high heat). One of the things they do is to act as "chaperones" that help other proteins fold into their proper shape. It's hypothesized that during periods of prolonged environmental stress, these proteins get overwhelmed and can't keep up with the chaperoning job. When they help other proteins fold, they mask minor variations in them that result from mutations (kind of like how a girdle will make all kinds of figures look similar). If they can't keep up with the demand, lots of proteins are running around the cell without their girdles (if you follow my analogy) and thus their inherent variation becomes "exposed" to selection. So, variation becomes "visible" when the environment changes.

fargaloo
Apr. 10, 2012, 12:37 AM
Best. Thread. Ever.

I am decidedly unscientific so I can only add the story of evolution according to my 10 yr old son (as told to me from the back seat of the car after I picked him up from daycare).

Me: "So..how was school? What did you learn"
Son: "Lots. Did you know we used to be fish?"
Me: "Well...I don't think we were fish, exactly"
Son: "Yes we were. First we were fish, then we were monkeys, then we were ugly hairy naked guys"

I know right now there are science teachers everywhere quietly weeping :lol:

I like your son :)

alterhorse
Apr. 10, 2012, 12:54 AM
Interesting. There was a fair bit of research a few years ago into the role of heat shock proteins (stress proteins in general) in rapid evolutionary change. HSPs are proteins that are expressed mostly when the organism is stressed (for example, exposed to high heat). One of the things they do is to act as "chaperones" that help other proteins fold into their proper shape. It's hypothesized that during periods of prolonged environmental stress, these proteins get overwhelmed and can't keep up with the chaperoning job. When they help other proteins fold, they mask minor variations in them that result from mutations (kind of like how a girdle will make all kinds of figures look similar). If they can't keep up with the demand, lots of proteins are running around the cell without their girdles (if you follow my analogy) and thus their inherent variation becomes "exposed" to selection. So, variation becomes "visible" when the environment changes.

Cool! That would sort of make evolution a "built in" function in living things. :)

equidae
Apr. 10, 2012, 05:57 AM
MVP:

I'm a non-theist who believes in science and tangible facts but I have a hard time explaining 'where we came from' to people who don't believe or who are on the fence. People will say to me, 'So you actually believe we came from the bottom of the sea', and I'll go 'Yup'!- How is it so inconceivable for them to comprehend something like that when they have no problem with the idea of a baby forming out of a bunch of microscopic cells?

I can see how we came from an common ancestor but I can't explain it simply enough to them. I understand what I read in my books but I cannot regurgitate it for anyone else. I end up just telling them I believe what I believe without being able to explain myself and saying something like 'Science is very complex'. To me, there is no question of evolution as it is very obvious when you look around the world and simply observe. But I understand not everyone is as perceptive to the small things and are not constantly looking to put the connections together like a more scientifically eager person is.

Anyway, How can I stand up for myself without getting too deep or too complex for the common public? I need just a few sentences to back up all of what is scientifically holy!!

bumknees
Apr. 10, 2012, 06:50 AM
I have my own theory on this subject and I may be all wrong on it and will not be offended at all if those who are a lot smarter than I can dream of being on this subject tell me Im nuts..

But every once in a while nature hick ups so to speak. and a group of people gets slammed with things and over loads the system.
Maybe lets say a body gets slammed with 2 or 3 diffrent kinds but of the same ''family'' of cancer. Just to see or maybe find a way to prevent it with in the body for future generations. Did that make sense?
It is just one person of the immedate family but there are many in the family who have had the particular family of cancer. I think it mybe natures way of finding a way to prevent before it happens type thing.

Or a physical thing or many physical things happens in a family or again to one person in that family over a short period of time and again family reserch shows that many have had same things of the same type. Physical as in a certian family of birth defect.

I just think it is natures way of prepping itself for the next step so things no longer are an ''everyday'' problem for humans to face.
Think about it there are some illness/defects of the past that we know no longer exists even though when they left humans science was not around to fight it. It just went ''poof''... But every now and then it pops up and scares the pee out of everyone...

alterhorse
Apr. 10, 2012, 07:37 AM
I have my own theory on this subject and I may be all wrong on it and will not be offended at all if those who are a lot smarter than I can dream of being on this subject tell me Im nuts..

But every once in a while nature hick ups so to speak. and a group of people gets slammed with things and over loads the system.
Maybe lets say a body gets slammed with 2 or 3 diffrent kinds but of the same ''family'' of cancer. Just to see or maybe find a way to prevent it with in the body for future generations. Did that make sense?
It is just one person of the immedate family but there are many in the family who have had the particular family of cancer. I think it mybe natures way of finding a way to prevent before it happens type thing.

Or a physical thing or many physical things happens in a family or again to one person in that family over a short period of time and again family reserch shows that many have had same things of the same type. Physical as in a certian family of birth defect.

I just think it is natures way of prepping itself for the next step so things no longer are an ''everyday'' problem for humans to face.
Think about it there are some illness/defects of the past that we know no longer exists even though when they left humans science was not around to fight it. It just went ''poof''... But every now and then it pops up and scares the pee out of everyone...

I'm not an expert but I do enjoy contemplating theories too..

I'd use the example of Aids, and Bubonic plague to illustrate your point (if I'm understanding the point correctly).

There is a segment of the population that is naturally immune to Aids, there is also a segment of the population that is naturally immune to Bubonic plague. That immunity is thought to stem from some genetic mutation that only those immune people possess.

Now to touch on your theory, one might speculate that at one point in time when people were living in hunter gatherer groups, that occasionally one of those groups would pick up a deadly disease that would kill off some of the group, but leave others alive due to some genetic differences that only some in that group possess.

The disease doesn't kill off half the human life on the earth because groups of people at that point in time are not living close to one another.

But the survivors of the group that had the disease would live on and have children, and in that way a larger percentage of the population would eventually have that genetic difference that protects them from that disease even though they were never a part of any group that was exposed to the disease.

The same thing would be true with deformities, because if the deformity hindered survival, those with the deformity would parish, and not be able to have children to pass on their deformity causing genes.

The only other possible source of a transfer if immunity I'm aware of would be mother's milk. So one might speculate that any mother that had a gene that protected them from a disease that they actually contracted, and then successfully fought off, might then possess antibodies that they could pass on to to their children through their mothers milk, and then that child might become immune to that particular disease even if they didn't inherit the gene that made their mother immune.

bumknees
Apr. 10, 2012, 08:10 AM
Yes alter horse but to take it even a step further.

Because the fetus is sharing the mothers blood supply while inutero(sp) they recieve the immunities to lets say AIDS because iirc it is a blood illness.
Or at least some because we know that there have been babies born to some HIV/AIDS positive females with out the virus. Is it possible for us to assume that child has some sort of natural immunity? Do to sharing of the blood system with its mother?

pegasus209
May. 11, 2012, 03:36 PM
Really interesting read.. enjoying this thread! Carry on folks :)

RacetrackReject
May. 11, 2012, 04:54 PM
Great thread. Now we just need a physicist and a mathematician to discuss the God particle and the theory of everything and my day would be complete..lol.

pegasus209
May. 11, 2012, 05:20 PM
Great thread. Now we just need a physicist and a mathematician to discuss the God particle and the theory of everything and my day would be complete..lol.
Agreed. I'm hoping for a physicist too-- have questions. :D

subk
May. 11, 2012, 05:45 PM
Very interesting thread. Although I've never seen Natural Selection and the existence of a God as being mutually exclusive to each other, or even had a problem with the idea of Natural Selection and Christianity coexisting. It's like arguing over what type of paintbrush Michelangelo used--completely beside the point.

Long Spot
May. 12, 2012, 12:42 AM
Bumping back up to page one, because I was really enjoying this thread with my husband last OT day. We were reading it to each other and having awesome discussions.

Sunsets
May. 12, 2012, 07:16 AM
Because the fetus is sharing the mothers blood supply while inutero(sp) they recieve the immunities to lets say AIDS because iirc it is a blood illness.
Or at least some because we know that there have been babies born to some HIV/AIDS positive females with out the virus. Is it possible for us to assume that child has some sort of natural immunity? Do to sharing of the blood system with its mother?

Immunologist here:

Not quite. Mom and baby don't share a blood supply. The placental barrier prevents that. Nutrients and oxygen (and viruses like HIV!) can diffuse across it, but not usually anything nothing larger than that.

Now, when you say "transfer of immunity" you're talking about antibodies, which are but one small part of the immune response. But they are the one thing that we can transfer. Everything else is based on our own cells, and aside from giving someone a bone marrow transplant, we can't transfer those!

Transfer of antibody from mom to kid is accomplished via breast-feeding (in the colostrum). That gives baby some pre-formed immunity to fight off pathogens while the kid's own immune system revs up and starts developing memory responses.

Now, onto AIDS. It is true that HIV is found in blood, however, most cases of babies being born free of the virus are due to the treament of mom with anti-retroviral drugs. That knocks the virus back enough that its not actively replicating and gives the baby a chance to develop without getting infected.

Unfortunately, acquired immunity to HIV is pretty much impossible to develop because the HIV virus infects the very cells we need to establish an immune response. So transfer of antibodies can't happen, mostly because we never make effective neutralizing antibodies against the virus.

And FINALLY (and this ties back into our discussion about genes) there are some humans out there who are apparently "immune" to AIDS. Turns out they are resistant to infection because they have a mutation in one of the cell surface proteins that HIV needs to latch onto to infect cells.

DieBlaueReiterin
May. 12, 2012, 11:11 AM
Very interesting thread. Although I've never seen Natural Selection and the existence of a God as being mutually exclusive to each other, or even had a problem with the idea of Natural Selection and Christianity coexisting. It's like arguing over what type of paintbrush Michelangelo used--completely beside the point.

i'm not so sure about that. doesn't the christian creation myth state that humans and animals were created whole cloth and appeared on Earth all at once, in their current form? how can you reconcile the two?

mvp
May. 27, 2012, 11:20 PM
For Memorial Day Weekend's OT Day:

Here's a modern-day statement/recipe of Evolution By Natural Selection.

1. Variation. Individual organisms need to differ.

2. Inheritance. Those differences need to transfer between parents and offspring. Though Darwin made room for the possibility that traits acquired during one individual's lifetime could be transmitted to offspring, the hardcore neo-Darwinians of the 1890s excluded that possibility (known as neo-Lamarckism).

3. Fecundity. Every individual tries to leave as many offspring as possible. Always. All of 'em. Without this fact, imported from Thomas Malthus, there's no scarcity to create competition.

4. Unequal, non-random survival. Presumably caused by the culling hand of selection. So not all survive, and there is a pattern that is orderly enough to have a cause behind it.

mvp
Nov. 21, 2012, 07:12 PM
Bumpin it up for more fun on Thanksgiving.

Gestalt
Nov. 21, 2012, 07:37 PM
Hey, glad you bumped it, I missed it the first go around. :)

I watched a tv program about mermaids. Yes it was a stretch for the imagination, but they touched on something that made me go "uhhehh?" It was about a village somewhere in Africa (??) and dolphins helped the fishermen by driving fish into the bay. Also, supposedly there have been sharks and whales harvested that had very strange knives embedded in them.

So my long winded question is: is it possible some form of man became water bound rather than land?

mvp
Nov. 21, 2012, 07:51 PM
Immunologist here:

Not quite. Mom and baby don't share a blood supply. The placental barrier prevents that.

And another cool evolutionary feature: Fetal hemoglobin. That shizzle binds to oxygen more strongly than does adult hemoglobin. Momma can be jonesing for oxygen and her unborn offspring will take what it can, first.

mvp
Nov. 21, 2012, 08:02 PM
Hey, glad you bumped it, I missed it the first go around. :)

I watched a tv program about mermaids. Yes it was a stretch for the imagination, but they touched on something that made me go "uhhehh?" It was about a village somewhere in Africa (??) and dolphins helped the fishermen by driving fish into the bay. Also, supposedly there have been sharks and whales harvested that had very strange knives embedded in them.

So my long winded question is: is it possible some form of man became water bound rather than land?

Do you mean "Will our species be able to remove oxygen from water via gills and whatnot?" Or do you imagine that we will remain air-breathing swimmers?

The right way to ask this question is to think a bit like an engineer. So, "How many physical and physiological parts would have to change for an air-breathing species to become a water-breathing one?" That's far more complicated than asking what would need to be rearranged in out "bauplan" (body architecture) for a land-dwelling, generalist quadruped to become a so-so or even good swimmer.

And then you have to ask yourself just how mediocre all of those mid-steps in a design change could be in order for those evolving generations to survive and out-reproduce competitors.

You'd also have to consider two more points:

What change in environmental factors would make a so-so swimmer a good candidate for survival and reproduction? What would change in the living- and non-living world?

Last, and hardest for evolutionary biologists to consider: How many "genetic steps" are involved in a small or large re-design of an organism. Leaving aside for the moment the requirement that each generation be at least "good enough" at survival though not a well-designed specialist at swimming or getting around on land, you'd need to know how many genes are involved in making those various changes to design that would get the job done. IMO, redesigns that are *genetically* too involved are rarely seen. But then again, we know precious little about how very different-looking bauplane (plural for body plans) are similar or different in their genetic bases.

So not so simple a question, eh?

mvp
Nov. 21, 2012, 08:07 PM
i'm not so sure about that. doesn't the christian creation myth state that humans and animals were created whole cloth and appeared on Earth all at once, in their current form? how can you reconcile the two?

Yes, the hardest form of the Creation Story comes from Genesis. And 19th-century biblical scholars found more than one translation of the Bible, so there are slight variations in the order of things.

The professionalization of biology in the second half of the 19th-century, and the success of the physical sciences before that... while folks were doing "Natural Theology" where you looked for insights about God in the appearance of nature, set the stage for an enormous and quite serious contest for authority.

LauraKY
Nov. 21, 2012, 08:32 PM
Yes.

Count on it. Bet on it. Too bad you won't be there. Too bad currency won't exist any more. But if you can find some post-Apocalypse endzone to do a dance in, I suggest you get nekkid and let 'er rip.

Celebrate your having been right because you'll die of radiation sickness or starvation or heinous mano-a-mano fighting with your species surrounded by toilet seat saddles and bugs.

LOL, back in the 60's when we had the duck and cover drills in schools, my fathers mantra (we lived not too far from Washington in the Maryland burbs)...drive towards the light.

foggybok
Nov. 21, 2012, 10:37 PM
And another cool evolutionary feature: Fetal hemoglobin. That shizzle binds to oxygen more strongly than does adult hemoglobin. Momma can be jonesing for oxygen and her unborn offspring will take what it can, first.

And fetal hemoblobin is protective in sickle cell anemia! That's why some current therapies try to shift adult Hb back to HbF.....

Another fun adaptation... hepcidin. Hepcidin is the master regulator of iron processing. It used to be thought of as an anti-microbial and indeed was initially called HAMP or hepatic anti-microbial protein. What it really is, is an iron regulator. Increased hepcidin level leads to sequestration of iron in the RE cells of the body. In the case of infection, reducing available iron starves the microbes and allows the host to survive an infection. What it also does is cause anemia because the host does not get any iron (even though the body has a lot of iron stored). So then you have Anemia of Chronic Disease or Anemia of Inflammation as is is called these days. So the host makes itself anemic (non-fatal) to prevent a fatal infection. Infection goes away and host recovers from anemia. pretty cool!

HPFarmette
Nov. 23, 2012, 12:32 PM
Hey, glad you bumped it, I missed it the first go around. :)

I watched a tv program about mermaids. Yes it was a stretch for the imagination, but they touched on something that made me go "uhhehh?" It was about a village somewhere in Africa (??) and dolphins helped the fishermen by driving fish into the bay. Also, supposedly there have been sharks and whales harvested that had very strange knives embedded in them.

So my long winded question is: is it possible some form of man became water bound rather than land?

One of my favorite books is The Descent of Woman, by I think, Robin Morgan. Theorizes about a stage when people lived close to/in the water and the influence of females on evolution. Sadly may be out of print ....edit....maybe not!

http://www.amazon.com/Descent-Woman-Classic-Study-Evolution/dp/0285627007/ref=sr_1_1?s=books&ie=UTF8&qid=1353692031&sr=1-1&keywords=The+Descent+of+Woman#reader_0285627007

Kairoshorses
Nov. 23, 2012, 12:45 PM
Why are male/female brains different, and is it just the structure that makes them different? Backstory: I was a huge believer in social construction/nurture over nature until I had two boys and went through menopause--AND watched a person I love go from male to female as an adult. I watched the ability to focus/compartmentalize lesson (and the ability to empathize and think relationally increase) as this person took female hormones/surpressed male hormones. I watched my boys go from sweet to distant and unable to relate two things. And I have gone from caring to yelling a lot. :) So maybe this is less about brain physiology and more about hormones.....but still, why are we so different?

mvp
Nov. 23, 2012, 12:49 PM
One of my favorite books is The Descent of Woman, by I think, Robin Morgan. Theorizes about a stage when people lived close to/in the water and the influence of females on evolution. Sadly may be out of print ....edit....maybe not!

http://www.amazon.com/Descent-Woman-Classic-Study-Evolution/dp/0285627007/ref=sr_1_1?s=books&ie=UTF8&qid=1353692031&sr=1-1&keywords=The+Descent+of+Woman#reader_0285627007

Never seen it. Got a synopsis for us?

Females have been (begrudgingly) given a credit for driving evolution mainly in scenarios where sexual selection has a greater effect than natural selection.

She who does the picking gets to set the standards for males' reproductive success.

mvp
Nov. 23, 2012, 01:12 PM
Why are male/female brains different, and is it just the structure that makes them different? Backstory: I was a huge believer in social construction/nurture over nature until I had two boys and went through menopause--AND watched a person I love go from male to female as an adult. I watched the ability to focus/compartmentalize lesson (and the ability to empathize and think relationally increase) as this person took female hormones/surpressed male hormones. I watched my boys go from sweet to distant and unable to relate two things. And I have gone from caring to yelling a lot. :) So maybe this is less about brain physiology and more about hormones.....but still, why are we so different?

First, I'm with you with respect to social construction... even of the divide between nature and nurture. Oh, yeah, and just who creates all of these compelling accounts of nature as well as the standards for sorting good scientific explanations from bad ones? It's tautological when a species creates it's own origin myth at best. At worst (and as is usually the case), the powerful members among that species control the terms of interpretation.

Which brings me to your topic-- finding a material (physical) basis for cognitive stuff. A very old question-- goes way back to the Enlightenment at least. And with evolution plus ambient sexism layered over that project, it's gosh darn hard to find really good, objective ideas.

I couldn't begin to sort out the effects of personal history, brain function and hormones' effect on the behavior traits you saw change. But it's cool that you can sort out the possible causes.

Other tidbits to consider:

Is menopause an evolutionary adaptation or a side-effect of something else?

The best men were raised to treat pets well, particularly cats.

jetsmom
Nov. 23, 2012, 01:55 PM
BIG laugh out loud on this one!

My dumb question: How did humans evolve such big craniums when it makes childbirth so risky for the mother? Seems like smaller craniums would select out because mom/baby would survive--over the larger craniumed, more intelligent.

Or at least pointed ones would make it easier!

ReSomething
Nov. 23, 2012, 02:25 PM
OP, you haven't read the Descent of Woman? This is going to be a bad synopsis because I read it when I was 17, but here goes: We evolved as estuarine/marine/aquatic mammals with the greatest impact a result of female survival.

There's quite a bit about why we are hairless, why we have beaky noses, why we stand upright, why we have a poor sense of smell but good color vision. If W = the coefficient of fitness it pretty much covers how we survived and prospered and has some good arguments, at least in counterpoint to the Naked Ape which was out at the same time.