Evolution
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Just to kill this particular subject because it's getting annoying can we come to a consensus on what "Theory" means in this thread? i'd go with the dictionary http://www.merriam-webster.com/dictionary/theory or a suitable scientific meaning.
If you've taken any medicine in the past decade, you can thank evolutionary theory for your health.
Putting aside theoretical scenarios and high level discourse. Evolution is successful as a theory because when you apply it to real world applications, it works. Pharmaceutical companies aren't basing their research into new drugs in Intelligent Design. There really is no more efficient way to cut through the nonsense than looking at the real world, I think.
Is relativity real? Well, my GPS tells me where I am reliably, and it was designed following the rules of relativity. So I give it a pass. Electromagnetism? I use computers and wireless communications all the time. Atomic theory? Nuclear power and atom bombs.
Evolution? Modern medicine is founded on it. When they ask you if your family has a history of some disease? That's because evolution dictates that you'll likely share their characteristics. If evolution didn't work the way we understand it to, they wouldn't bother. Germs continually evolve, seeing as their life cycles are so quick, and drugs are developed to keep up with them. If they didn't evolve, we would still be using penicillin.
So, unless you can show how all these people are making real contributions to the real world based on flawed premises, you have to agree that they must be right.
I call it my theory of the origin of theories. Lots of lies have been spread about since we started writing things down. The ones that persist have been the ones we put to the test and continue to use.
Putting aside theoretical scenarios and high level discourse. Evolution is successful as a theory because when you apply it to real world applications, it works. Pharmaceutical companies aren't basing their research into new drugs in Intelligent Design. There really is no more efficient way to cut through the nonsense than looking at the real world, I think.
Is relativity real? Well, my GPS tells me where I am reliably, and it was designed following the rules of relativity. So I give it a pass. Electromagnetism? I use computers and wireless communications all the time. Atomic theory? Nuclear power and atom bombs.
Evolution? Modern medicine is founded on it. When they ask you if your family has a history of some disease? That's because evolution dictates that you'll likely share their characteristics. If evolution didn't work the way we understand it to, they wouldn't bother. Germs continually evolve, seeing as their life cycles are so quick, and drugs are developed to keep up with them. If they didn't evolve, we would still be using penicillin.
So, unless you can show how all these people are making real contributions to the real world based on flawed premises, you have to agree that they must be right.
I call it my theory of the origin of theories. Lots of lies have been spread about since we started writing things down. The ones that persist have been the ones we put to the test and continue to use.
look through this thread, hell there was one with Ecoli and vitamin C * think it was vitamin C, may have been citrus... anyone know what im talking about* awhile back.Don said:
About the relationship between law and theory.
A theory is a comprehensive explanation for a given phenomenon. A law is the mathematical equation that describes this explanation. A theory can have several laws, but the laws alone don't explain the phenomenon.
Case in point, E=mc^2 is a law of relativity, but just being able to memorize the law won't make you understand it. You have to actually study the theory to understand what the symbols mean.
A theory is a comprehensive explanation for a given phenomenon. A law is the mathematical equation that describes this explanation. A theory can have several laws, but the laws alone don't explain the phenomenon.
Case in point, E=mc^2 is a law of relativity, but just being able to memorize the law won't make you understand it. You have to actually study the theory to understand what the symbols mean.
Well first of all we have to stop looking at evolution as a conscious choice made by organisms or an intelligent designer. Evolution is random, a mutant is born into a population and if it's new genes give it an advantage due to a selection pressure then it survives to have loads of progeny. The mutation becomes the norm and the gene pool changes. This happens repeatedly over many generations and so the species evolves into another and then another etc. Species also go extinct, and split off into two separate species. Also every species alive today is a current generation, this is why you can't see every missing link wandering the globe and also why there are still monkeys...in summation evolution is the random process by which mutants take over from the original. It can be proven by introducing selection pressures onto colonies of microbes living in a Petri dish. Or by studying examples like MRSA and rats that are resistant to Warfarin.
SCIENTIFIC theory.Glademaster said:
An idea or notion is a hypothesis, not a theory.
You start by saying: "Pah to your blondes, Frederick, for it is the brunettes who have the strongest sex-drives!"
Frederick tells you you're talking tosh.
You formalise your statement into a hypothesis: "Women with natural hair colour darker than #404040 have higher sex drives than those with natural hair colour paler than #B0D0D0."
You then devise an experiment to test this hypothesis, using ... erm ... well, I'm not actually sure how to go about testing that one but anyway, you'd need a lot of women with no idea what you were up to, a lot of opportunities for sex and a way to record how much sex happened and with whom ... accurately. You'd also need to know their natural hair colours.
Having gathered your data, you then analyse it and come up with a probability that you were wrong. If your data indicate that the brunettes are more up for it than the blondes and the probability that the results you got arose from sheer chance is less than 5%, you write it all up and send it off to Nature, it goes through the peer review process, if it makes it past that it gets published and if noone shoots big holes in it or runs a better experiment that gets results that don't support it, your hypothesis gets accepted as a theory.
What we have, according to mitochondrial DNA drift analysis, is a shared female ancestor a long way back.
Once upon a time, there were ape-like things. They had baby ape-like things, which were almost all very similar to their parents but not all alike. Some of those babies had babies with others of those babies, and those grandchildren of the ones first mentioned had children of their own and so on, and so the ape-like things continued to breed and wander and mingle in the forests of Pangea. As different parts of Pangea had different conditions at the time, different traits were favoured in different parts, and the apes with the traits favoured by one location tended to do better there, while those with less favourable traits tended not to do so well and either moved to places where they were better suited to having grandchildren or had fewer grandchildren until eventually there were none.
Over thousands of generations, the ape-like things in different areas changed more and more in visible (like the shapes of their hands) and invisible (like the numbers of chromosomes they had) ways until they were so different from each other that they could not have babies together and instead stuck with their local populations. Thus speciation had happened: one species had given rise to two.
This process happened again and again, with the ape-like things in each group always obviously the same sort of ape-like thing as their parents but never quite identical to their great-great-great-grandparents, not that anyone was checking.
When Pangea split up and drifted apart, the groups in different areas were separated by seas and oceans, and conditions changed a lot, favouring different traits and causing the species in what became South America [http://rainforests.mongabay.com/0410.htm] to evolve rather differently from those in what became Madagascar [http://www.wildmadagascar.org/wildlife/lemurs.html] and those in south-east Asia [http://goseasia.about.com/od/malaysiastopattractions/a/sepilok.htm]. Those that remained in Africa split into two groups, of which one eventually gave rise to today's gorillas and the other split further into two that evolved into chimpanzees and early humans.
What mitochondria have to do with it goes back further. Way back in the primordial ooze days, a mess of DNA with a membrane around it engulfed a mess of DNA with a membrane around it. Instead of one of them digesting the other or the two merging into one, they co-existed, with the smaller one existing in a membrane bubble within the larger. When the smaller one divided, the membrane bubble divided too, to the larger cell then had two of those little bacterium-like things in separate pockets within it, then four. When it in turn divided, the two cells formed had some each. As this went on, the two species both benefited from their unusual relationship, and they pretty much took over the world. No, really. You find the same arrangement in fungi, green plants, plankton and all large animals, along with a few other adaptations that distinguish those things from bacteria [http://en.wikipedia.org/wiki/Eukaryote].
One of those changes is sexuality. Random mutations happen over time. DNA gets changed by transcription errors or radioactivity. It happens. Sometimes it's fatal. Sometimes it's beneficial. Sometimes it's utterly irrelevant. If you've only got one copy of each gene, that's about it. If you have two copies of each, though, you can get away with having changes in one as long as the other keeps working, and you might just get lucky and get one essential gene turned into a helpful variation on it, which would have been fatal to a single-chromosome creature.
Once you've got two of each gene on two nearly-identical chromosomes, you could, conceivably (heh, pun), meet up with another thing a lot like yourself and rather than just duplicating yourself, make a new baby that's got a copy of one of your chromosomes and a copy of one of your partner's chromosomes. Fungi do this. If you've got two version of the chromosome, A1 and A2, and your partner's got two versions, A3 and A4, the possible offspring are:
A1,A3; A2,A3; A1,A4; A2,A4.
Bear in mind that evolution isn't about more things just like you being around in a thousand years' time. It's about a gene being around in a thousand generations. The gene that allows that recombination to happen has thereby given itself a way to get into a wider range of offspring, so it's got a better chance of making it through the next winter or the next sudden influx of cold water from a glacial lake or whatever.
The next change is to split the chromosome. Now you get A1,A2,B1,B2 meeting A3,A4,B3,B4 and producing:
A1,A3,B1,B3; A1,A4,B1,B3; A1,A3,B1,B4; A1,A4,B1,B4;
A1,A3,B2,B3; A1,A4,B2,B3; A1,A3,B2,B4; A1,A4,B2,B4;
A2,A3,B1,B3; A2,A4,B1,B3; A2,A3,B1,B4; A2,A4,B1,B4;
A2,A3,B2,B3; A2,A4,B2,B3; A2,A3,B2,B4; A2,A4,B2,B4;
The more it splits, the more extra on the ends you need and the more resources you're using to create each new cell but the more it splits the faster you can mix and change and the more independently versions of genes can meet up.
Without a partner, you duplicate yourself. There is one possible outcome.
With a partner and one chromosome pair, you each contribute one version, producing four possible offspring.
With a partner and two chromosome pairs, you each contribute one version of each chromosome, producing sixteen possible offspring.
With a partner and three chromosome pairs, you each contribute one version of each chromosome, producing sixty-four possible offspring.
With a partner and four chromosome pairs, you each contribute one version of each chromosome, producing 256 possible offspring.
Next change: sexual dimorphism. Whassat? Morph: shape. Di-: two. Sexual: sexual, duh. Males and females, and not exactly the same, that's what.
Salmon spray their gametes, their little half-a-cell thingies, into the stream, and they all mix together and form babies at random from all the salmon that came back.
Frogs grapple in pairs and release together, allowing female frogs to select male frogs that are obviously wonderful sources of wonderful DNA because they're not only alive and at the pond but also croaking really loudly. Other male frogs join in anyway, but it works.
Birds pair rather more carefully and produce much smaller broods and care for them, and in birds we see dimorphism. Male and female peafowl are rather different because, as explained in the video on page 1, the males display to attract female attention and the females are camouflaged. Some species display much less dimorphism, like corvids and pigeons.
Dimorphism can go to extremes, as seen in some spiders. Compare the long-lived female black widow with her generally single-use male relatives for an examples.
With selective mating as seen in any species with courtship (yes, including us) there comes a benefit associated with more secure couplings, for want of a better word. It's no good picking your partner with great care if you're going for the salmon approach to actual reproduction, after all, and if you can deliver it right to the target you don't need to produce gallons of semen. This has led to sexual dimorphism in sexual organs. Instead of just spurting out half cells and hoping they stick together, animals and plants have different organs producing different styles of partial cell. Some plants have male and female parts and clever ways to avoid fertilising themselves. Animals generally have only one kind. I said generally. Put the slug down. This is why penises and vaginas exist and fit together so well.
Can I leave out the evolution of the G-spot? Yes? Great! Thanks.
Having got male sexual bits and female sexual bits, we also got male partial cells and female partial cells, and the way it works is that the male part fuses with the female part and delivers its DNA, its copies of one version of each of the father's chromosomes, into the mother's partial cell, where the two DNA packets are combined to form the nuclear DNA (wikipedia link above will tell you about it) of the new baby ... whatever.
That's all the male delivers, though. The male's mitochondria in that delivery vehicle get left there. It's the female's mitochondria that get passed on in the cytoplasm and down through the generation. There's no exchange of genetic material there. They're clones. They just mutate at random as the years go by.
This means we scientific geeky types can get the DNA out of something's mitochondria and compare it to the DNA from something else's mitochondria and see how many differences there are and thereby draw up a family tree showing which things are more closely related to which other things by female line only and, given certain assumptions about how rapidly those mutations have been happening, how many generations back their female-line ancestry split.
It's by comparing mDNA that we get the pretty charts of tribal descents within humanity and of species descents within apes, all primates, all mammals, all vertebrae, all animals and even, if you were to go that far, all eukaryotes. You are, you probably won't be surprised to learn, more closely related to manatees than to eucalyptus ... unless you're a tree, which would make you unique among forum visitors, as far as I know.
Anyone wanting to know more about it, hit google with phrases like mitochondrial DNA family tree [http://www.google.co.uk/images?q=mitochondrial+DNA+family+tree] or mitochondrial Eve [http://www.google.co.uk/search?q=mitochondrial+Eve].
Maybe they choose their mates by racing. They run across the plains from one bend in the river to another, and the ones that get there first get to mate with each other, and the ones that get there last get mocked. Maybe the cheetahs eat the slowest. Ever seen how much top athletes eat? Being able to get food (and to get a wide variety of food) makes for a healthier animal, and that makes them more attractive or more likely to still be breathing, either way.omega 616 said:
That is pretty much how wolves do it, only it's not a race. The male wolves stare each other down, wrestle or outright fight for dominance among the males, the females do the same among themselves, the cubs have their own heirarchy for practice and the top dog and top *****, the Alphas, have the babies. Everyone else, beign aunts, uncles and cousins, helps raise them or sods off to some other part of the forest to keep the DNA mixing around between packs.
You obviously haven't looked very far. Did you ever think to ask any biologists rather then just randomers on the internet.jawakiller said:
Anyways, I would think that the fact that evolutionary biology is the main basis for our understanding of immunology and genetics as well as many other fields of biology, would be more then enough evidence that it's an effective model for how species change over time, but if that doesn't do it for you there's still the entire fossil record in addition to every bit of geological research done up until this point.
I would pause before calling people ignorant since it's pretty clear that you haven't a clue what a theory is. It doesn't mean the same thing in scientific parlance as it does in colloquial language. In other words it's not just a guess but rather the highest form of proof that can be reached with the scientific method and the amalgamation of all of the knowledge pertaining to the subject it concerns, that has been collected so far. Saying that facts should be used in stead of theory is really quite backward because facts are what theories are constructed from.
Woah, did you just mention dogs? Dogs are invalid because it is not evolution; it is humans selecting traits they want in the animals and breeding them to emphasise them, often to the point at which the animal would not survive naturally; they are all still canis lupus familiaris. Add to that the fact that there are limits to how large or small a dog you can breed and that all dogs breeds can mate to produce viable offspring; therefore they are not different species. Wolves can interbreed with canis lupus familiaris to produce viable offspring, showing they are still effectively wolves; hybridisation is what is threatening the dingos with "extinction" in Australia, just as feral cats in the UK are rarely pure feral and therefore regarded as endangered. Technically though I can't use dingos in the argument because they are human-created species anyway. Naturally chihuahuas and great danes didn't occur; human intervention is not viable proof of evolution in dogs. Going back to what I said about dog size; the fact there is an upper and a lower limit to how large or small you can breed a dog would indicate there is a limitation in the genes of the animal itself.Spot1990 said:
Did no one read my links about how domestication causes physical changes within animals!?Don said:
http://en.wikipedia.org/wiki/TheoryAmpersand said:
He isn't saying evolution isn't true, he's saying we've yet to prove it with undoubted certainty. The same can be said for MOST scientific theories, like, for example, gravity. It's the fact that most people see this idea as factual without the research to discuss it in any real sense that probably has him miffed.
Though I would agree that we shouldn't be calling random strangers ignorant.
To expand on that, in a lot of species the male's nuclear DNA can survive without him from the moment sex is over (or even from halfway through, in the case of the preying mantis, and not in the case of seahorses) but not without the female for quite a bit longer. In mammals, the minimum male commitment to the offspring is pretty much "two pumps and a squirt" whereas the female's commitment is rather bigger and takes a lot longer. This means women have to be careful whose babies they have while men can get away with just shooting it up anyone who'll let them and gee doesn't that sound like Friday night, men thinking every hole's a goal and women looking for Mr Right in all the wrong places? Of course, once a man has got as far as getting a woman pregnant, it's then in his interests to stick around, provide for and protect her while she's vulnerable and their babies thereafter and so on ... so, er, men get affectionate after sex and women get turned on by affection? Well, that's not that far from the truth, is it? If men are having a hard time finding mothers for their prospective babies, once they have got that far their DNA's more likely to get as far as grandchildren if they're willing to die for their families than if they're more liekly to sacrifice their families to save themselves. If they're having a great time, getting some every weekend, sometimes with two different women on two nights, then their DNA's best chances come from moving on to fresh conquests all the time. Noooo, that's nothing like human male behaviour, is it? Women, meanwhile, want a big, strong man who's full of self-confidence, has the means to provide for them and can protect them and will do both those things. Self-confidence is shown by a willingness to challenge other males for dominance and being able to protect them is shown by winning fights, so women instinctively go for bastards with flashy cars and hope they'll somehow turn out to have hearts of gold.legopelle said:
Depressing, eh?
I did debate with myself whether to use thousands or millions or billions or whatever, but in the end I decided that "thousands upon thousands" does turn into "millions upon millions" after a while, and I'm sure some development could happen in a couple of thousand years if the animal wasn't all that well adapted to the environment in the first place, so in the end, I just went for thousandsWolfEdge said:Fixed that for yaJonluw said:
It would be more accurate to say that it's not proven with undoubted certainty, the same as ALL other scientific theories. Because knowing anything with undoubted certainty is completely impossible, when regarding anything other then you're own existence( and that's a hole other discussion.) Nothing can ever be proven 100% however they can be proven beyond all reasonable doubt based on the evidence available to us at the moment and in that regard evolution is one of the most air tight theories there are. We understand evolution in much greater detail then we understand gravity( to use your own example)or indeed a lot of scientific theory and I can't think of any reason for people to contest it as virulently as they do.WolfEdge said: