Strictly speaking, Darwin's "theory of evolution by means of natural selection" is a theory that explains how life evolved once there was something to start evolving. However, abiogenesis is not necessarily all that mysterious. Keep in mind that there's no reason to think that the first life form was a cell. Heavens no! A cell is a complicated device. Even DNA is far too complex to be a good candidate for the first bit of life; even RNA is probably too complicated.

But it doesn't take that. All it takes is something that is capable of copying itself, with good (but not perfect) fidelity. Given that we are made of amino acids, it seems fairly likely, though far from certain, that it was an organic molecule made from amino acids (something like RNA, in other words, though probably simpler). Once these things were ticking, and competed for resources, more sophisticated forms would have arisen -- eventually leading to RNA, and cells, and DNA, and eukaryotic cells, and---well, and so on.

Keep in mind that biologists have reproduced most of the amino acids that we are made from in the lab, simply by simulating a primordial Earth atmosphere in test tubes as best we know it, and running electric shocks (to simulate lightning) through it, and shining UV lights on it (simulating sunlight) -- from inorganic chemicals to a brown soup of organic molecules. Keep in mind, too, that the origin of life may not be an extremely probable event. It can't be too improbable -- if it's the sort of thing that's unlikely to happen during the lifetime of the universe, it probably didn't happen. If, however, it is the sort of thing that only happens once every few hundred million years in an organic molecular soup -- well, it seems fairly likely, if so, that it happened on Earth, but it isn't necessarily easy to reproduce in the lab in a mere few years or decades. Alas.

Question: Can you explain the whole irreducible complexity thing then? I believe it's been posted several times that this is not a valid argument. but no one ever explained why.

Irreducible complexity in a nutshell: There are some organs and body parts that could not have gradually evolved, they would have had to pop out fully formed in order to be viable. Example used is usally an eye. The analogy used is: It's like a moustrap. You cannot start with a piece of wood and catch some mice, add a spring and catch some more mice, then add the metal bar and catch the maximum amount of mice. You must have every piece properly positioned and lined up or the whole thing is useless.

Vince, usually the eye is given as a good example of irreducible complexity. However, as was posted earlier there is evolutionary evidence of eyes that are just photosensitive cells that can bearly detect light to eyes that are actually better designed than the human eye, not just able to see better. I think squids are a good example of this.

Question: Can you explain the whole irreducible complexity thing then? I believe it's been posted several times that this is not a valid argument. but no one ever explained why.
Dawkins calls it the Argument from Personal Incredulity: "I personally don't see how that could have evolved; therefore, it cannot have evolved; therefore, someone must have created it." The problem is that this is only valid if the person making the claim is able to conceive of every possible evolutionary path, which they are not.


Irreducible complexity in a nutshell: There are some organs and body parts that could not have gradually evolved, they would have had to pop out fully formed in order to be viable. Example used is usally an eye.
See posts #511 and #516 (by me, as it happens) on eyes; see also this page (http://www.talkorigins.org/indexcc/CB/CB301.html). The eye is nice for us because it's incredibly easy to debunk, and was in fact debunked 150 years ago by Darwin himself. Other examples, like the bacterial flagellum so beloved by Behe, are sometimes harder, but there are evolutionary pathways (http://www.talkorigins.org/indexcc/CB/CB200_1.html). But even if you come up with a really tricky structure that we can't explain, that doesn't mean that it cannot in principle be explained -- it may just be that we don't know yet.


The analogy used is: It's like a moustrap. You cannot start with a piece of wood and catch some mice, add a spring and catch some more mice, then add the metal bar and catch the maximum amount of mice. You must have every piece properly positioned and lined up or the whole thing is useless.
A counter-example is an arch, which obviously won't stand up if even a single piece is missing -- and yet it can be built gradually with the help of scaffolding. Of course humans can construct machines that truly cannot be formed gradually, but just to show how fatuous Behe is, someone did show (http://www.fidelibus.com/mousetrap/01.htm) how a mousetrap could evolve by gradual selection and mutation (there are several mock-pathways proposed for this, too).

In other words, irreducible complexity arguments tend to spring from the paucity of the imagination, or lack of astuteness, on the part of people who propose them. If you show that something cannot have evolved step by step, then yes, evolution won't work, but no one has successfully showed that for anything, and it's not clear how it would be done.

Keep in mind that a common way for evolution to work is to hijack existing machinery for new purposes; e.g. a chemical is no longer necessary for its original purpose and so develops into doing something else. Consider the bombardier beetle (http://www.talkorigins.org/faqs/bombardier.html).

Okay, so there are some eyes that are less complicated than those of homo sapiens, and some that are more complicated (Tangent:I seem to recall reading somewhere that a squid's eyes are more like those of a human being than any other animals. Creepy!) To me this still doesn't answer the question: Are there some organs/appendages that will only be viable if they pop out fully grown, and cannot slowly mutate their way to usefullness over time? I once heard a guy use winged creatures as an example, he said if evolution was true then there would be an "in between" stage where the creature wing's were too underdeveloped to fly and its legs were too underdeveloped to walk, and they'd die out, so clearly, wings had to be shaped from the beginning by a designer.

Petter: Charles Colson mentions the life creating experiments in one of his books, he claims that the scientists "cooked the books" when they came up with them. For starters, he said they only mixed pure elements into their organic soup, and that pure elements are never found in nature, they're mixed up with a variety of substances. Second, they placed a filter over the organic soup to shield it from some of the harsher varieties of UV raditation while letting the good stuff get through, but filters of that kind did not exist for the proverbial primordial ooze.

Looked at the "evolving mousetrap" link. Interesting stuff. Of course, in my experience the mouse crams into the tiny nook and waits until you get tired of lurking by the entrance with a hammer, see "mouse hole". Evolutionary dead end or example of mouse evolving behavior to negate the evolution of house?

Okay, so there are some eyes that are less complicated than those of homo sapiens, and some that are more complicated (Tangent:I seem to recall reading somewhere that a squid's eyes are more like those of a human being than any other animals. Creepy!)
Even if there weren't, that wouldn't mean there never had been. Eyes just happen to be nice examples in that something like credible intermediate stages are around in living creatures today. This will typically not be the case; it's not like real intermediates stay around. In fact, 'intermediate' means precisely that, in hindsight, we look back and note that it went somewhere else.


To me this still doesn't answer the question:
Well, it never does, does it...


Are there some organs/appendages that will only be viable if they pop out fully grown, and cannot slowly mutate their way to usefullness over time?
ID proponents say so. They've never yet come up with an example that impresses actual biologists. I'm leaning, therefore, strongly towards an answer of 'no'.


I once heard a guy use winged creatures as an example, he said if evolution was true then there would be an "in between" stage where the creature wing's were too underdeveloped to fly and its legs were too underdeveloped to walk, and they'd die out, so clearly, wings had to be shaped from the beginning by a designer.
That's an incredibly, fantastically moronic example. Surely we can imagine an evolutionary pathway starting with a creature making its living something like a squirrel, then like a flying squirrel, then relying more and more on its gliding prowess, eventually becoming more like a bat, and, when it is able to rely on flying, its legs reducing in size as they are no longer needed? I could come up with a thousand more off-the-cuff suggestions; you could also look at what is currently believed about the evolution of birds from bipedal dinosaurs with wings evolving to aid jumping, gliding, eventually developing into true flight -- et cetera.


Charles Colson mentions the life creating experiments in one of his books, he claims that the scientists "cooked the books" when they came up with them. For starters, he said they only mixed pure elements into their organic soup, and that pure elements are never found in nature, they're mixed up with a variety of substances. Second, they placed a filter over the organic soup to shield it from some of the harsher varieties of UV raditation while letting the good stuff get through, but filters of that kind did not exist for the proverbial primordial ooze.
I'm comfortable with the notion that the scientists increased the odds manifold to get their results -- after all, they got their results in a few days, whereas in nature, it may have taken hundreds of millions of years. Keep in mind that we should probably be looking for a very improbable event as the origin of life. Not once-in-a-billion-billion-trillions improbable, but once-in-billions improbable.

Certainly, though, the final word is not in, and probably won't ever be in. Even once we are at a technological level where we can create life in a process similar to what might well happen in nature, we won't know whether this, or some other process, really did happen three billion years ago, and those early replicators were way too tiny and squishy to leave any fossil evidence.

Looked at the "evolving mousetrap" link. Interesting stuff. Of course, in my experience the mouse crams into the tiny nook and waits until you get tired of lurking by the entrance with a hammer, see "mouse hole". Evolutionary dead end or example of mouse evolving behavior to negate the evolution of house?
Obviously, mousetraps didn't evolve, so it may not be entirely legit. To your objections, however, the point of the nook is a nook small enough for the mouse to get trapped in, but large enough for us to squish the mouse in by reaching inside. Keep in mind, too, and this point is very important for real evolution -- it's not necessary for the mousetrap to evolve that, at every stage, every mouse be caught. All that's necessary is that each iteration is a little better than the last. A room with a nook is slightly better with a room without a nook, and that's what's important (if, that is, nooks in rooms are caused by genes, and those genes are inherited by the rooms' children...).

Sorry about the eye example, I wasn't trying to be deliberately obtuse ("I'll only believe it if you show me a lizard frog with a pupil BUT NO RETINA!") And the wing example was not my invention, it just came to mind since since this discussion was somewhat similar to that one.

Anyway, I'm quite comfortable with the idea of evolution in the short term, I can see it just by watching my younger brother breed his hog hunting dogs. He breeds the biggest ugliest males to the biggest, ugliest females and in a few years he has hideous looking creatures the size of shetland ponies. It's the part where the dogs become something of a wholly different genus, species, and family from what he originally started out with that I have trouble swallowing. (Say, some kind of giant tentacled plant that extrudes the scent of a female hog in heat, then wraps the lust lured male porcine up for the hunter to collect)

The eye example is good; I don't think it's a stupid example -- although an ignorant one, in the sense that anyone who's read Darwin's On the Origin of Species by the Means of Natural Selection should already be familiar with it. It's an obvious question to ask, and unless you've read about it or seen the many types of eyes the answer is far from obvious -- but it's also illustrative of how easy it is to fall into the fallacy of "It's so complicated; I just don't see how it could possibly have evolved by natural means". Remember Orgel's Second rule: "Evolution is cleverer than you are."

Now the wings example is just daft. The person who proposed that one is an idiot.

Has anyone read Goodwin's How the Leopard Changed His Spots?

It seems to be treated as 'fringe' science, though the overall approach is fascinating. It certainly fills a few gaps in the neo-Darwinian synthesis.

Darwin spent a lot of time in On the Origin of Species tearing down the artificial divisions of animals into 'species', 'genera', 'families', and so on, by pointing out that the distinctions are arbitrary. I encourage you to read the first few chapters of that book, which is really quite accessible -- of course it contains many errors, as we've learned a fair bit about evolution in the last century and a half, and Darwin didn't even know about genes and DNA -- but it's interesting and covers this topic pretty well. Dawkins calls it "the tyranny of the discontinuous mind"...

Maybe the best example is found in so-called ring species, seen in some types of lizards and gulls. A simplified example can be given by a hypothetical lizard in a circular mountain range around a lake or desert -- the lizards live only in the mountains. At the northernmost part of the range, there's a gap where they cannot cross. However, starting at one end, they encircle the whole thing. However, conditions are slightly different at any one part, so they evolve into slightly different races of lizards. The lizards at '12 o' clock' are clearly the same species as the neighbouring lizards at '1 o' clock', but they're a bit different in size, colouration, and so on.

Now here comes the tricky part: Although any two neighbouring populations interbreed freely, there is a gradual change around the ring, and if you were to take two lizards from the extreme ends, they would be quite different indeed. In fact -- and this sort of thing really does happen; look up ring species -- they would no longer interbreed, and so would be classified as different species, even though there's a smooth progression of lizards in between, each of which would interbreed with the other.

So species division is not something qualitative and absolute -- it's just a matter of enough changes having happened that individuals no longer interbreed.

Once a population has thus split into two species, they are free to diverge because no genetic material is being exchanged to homogenise the population -- this often happens due to geographical separation, as when part of a species is isolated by moving to an island or crossing a river.

Why is it so hard to think of a dog evolving into something quite different? Keep in mind that all the changes will be small, and the process will take millions of years. Plants and animals split hundreds of millions, maybe over a billion years ago -- plenty of time for lots and lots of evolutionary time.

It's been pointed out that if mice bred in such a fashion that each generation was just 1% bigger than the last -- a tiny change we wouldn't be able to visually discern -- then, assuming an average generation time of 5 years, in only a few hundred thousand years they'd be the size of elephants. This is too small to even look gradual in the fossil record.

Say, some kind of giant tentacled plant that extrudes the scent of a female hog in heat, then wraps the lust lured male porcine up for the hunter to collect
Nobody proposes that dogs would evolve into plants. They are highly specialised moving organisms; it seems very unlikely to me that there should be an evolutionary pathway from dogs to stationary traps that is smoothly positive. The scent thing is easy enough, though: If, by a chance mutation, a dog should happen to smell just a tiny bit like a female hog in heat, it might fool, say, one boar in a hundred to approach, and thus make it 1% more successful in the hunt. A tiny amount, admittedly, but it might thereby leave 1% more offspring. Because its children may inherit this trait and pass it on, it'll have 1% more children but 2% more grandchildren than the average dog, and almost three times as many descendants after a hundred generations (a measly few hundred years). As each successive scent modification would confer further benefits, we might well imagine a pathway whereby these specialised boar-hunting dogs come to smell more and more like female hogs in heat.

We might also envision that, because they are particularly good at hunting hogs, other adaptations that help with hog-hunting, such as being big and powerful and good at avoiding tusks, are variations (or mutations) that will do very well indeed whenever they happen to pop up in conjunction, so I would expect an increasingly heavy-set dog breed. If it comes to live separately from other dogs -- e.g. by living in hog territory as opposed to rabbit or fox or deer territory -- it would diverge further, including by mutations that don't affect adaptation at all but may affect reproductive compatibility -- and after a few thousand or tens of thousands of years, you'd almost certainly have a kind of dog-derivative that wouldn't, and possibly couldn't, interbreed with our contemporary dogs at all.

You make it all sound so logical....!!!!!! YOU'RE TRYING TO STEAL MY SOUL, AREN'T YOU!!! AWAY, FELL FIEND! (Brandishes cross in best Van Helsing 'Abraham, not that horrible Hugh Jackman Gabriel' tradition)

http://www.slimeculture.tv/assets/images/comics/left-behind(in-school).jpg

Feh, it figures that wimp Dawkins would need a gun...Jesus uses his bare hands!

http://www.youtube.com/watch?v=0IblzBerSFk