Mokele

Possibly, but my bet would be that increased tissue specialization and complexity are what got in the way. That the only salamander which can really regenerate perfectly is a very neotenic species (meaning it retains the juvenile form of the genus to adulthood) supports this, I feel. It also might have something to do with the nervous system, since one of my labmates used to work with them, and mentioned that they can only regenerate if the nerve is intact relatively close to the wound. Mokele

Quick answer: No. Evolution by natural selection does not depends on crisis, merely on limited resources. If a person has an allele that allows them to more effectively pass that allele on, it'll spread, even without strong selective pressure. That said, selective pressures *have* been reduced, which *does* reduce the *speed* of evolution. Also, there's always sexual selection. Every time you select a mate based on some characteristic like beauty (or even intelligence), you're engaging in an evolutionary mechanism.

I dunno, some of the troodontid dinosaurs were getting up there in brain size. Given than in 65 million years we went from rats to SFN, I wouldn't dismiss the possibility (though intellect and civ are always improbable) that dinosaurs could have produced civilization, had they had the chance. Mokele

Well, it *can* occur in vertebrates, most notably the axlotl salamander (a neotenic form of the common American genus Ambystoma), so it's possible in principle. There's probably some pretty strong biological and biochemical hurdles to cross before we get there, though. Mokele

A small and selfish part of me is saying "This is great! The more people who're turned into morons by the educational system, the fewer people who'll be effectively competing with me for jobs!" And an even darker corner of me is contemplating a long-term fix for the situation that involves the phrase "soylent green". Mokele

Actually, there *are* a few purely chemical connections between nerves, but they've very rare. Synapses are superior in that they can be moved, they can have their thresholds altered, they can be 'primed' by other chemicals, and are generally more complex and versatile. This allows for greater plasticity in both the individual and evolutionary timescales. Mokele

Garbage. If the O2 is high enough to kill cancerous cells, it'll kill *all* cells, and there's more than just cancer with a high metabolic rate (think brain cells). There's no way for it to specifically target cells that are cancerous, so any toxic effects would likely be lethal. Mokele

The others have effectively handled this in my absence, but I'd like to point out that the site can simply and easily be dismissed without even reading it. Why? Because it confuses abiogenesis with evolution, including Darwin's original formulation of evolution. This indicates that a) it's the product of someone with an axe to grind with evolution trying to bolster their agenda and, more importantly, b) that the writers of the site are barely even scientificly literate if they consider the two to be a single connected theory. Frankly, the title alone reeks enough of creationist garbage that the above refutations are simply icing on the cake. Mokele

If we had a hypersonic spyplane twenty years ago, why are we having so much trouble constructing one now? Oh, that's right, because the "aurora" project is bollocks.

HighWycombe

I've actually worked alongside someone working on them, and seen one working. Indeed they *are* quite efficient, but suffer from two problems. First, the timing needs to be very finely tuned and precise, or it just stops dead. Secondly, it makes a LOT of noise. And I mean that a 3 foot long, 3 inch wide tube of metal was producing noise that was nearly ear-splitting even *through* the high-quality noise-insulating headphones I was wearing. These things are *LOUD*. The diagram is pretty simple. Get a metal tube, cap one end, inject a fuel-air mixture, and ingite it. Repeat. If the mixture is right for the diameter of the tube, it'll transition from a sub-sonic deflagration wave into a super-sonic detonation wave, which, when it exits the end, imparts thrust. Mokele

No, that's not what they mean. Swansont was basically simply saying that chances of polypeptides forming from a pool of amino acids is much better than random chance alone indicates, because the molecules are interacting according to set, non-random laws. Bluenoise was pointing out that RNA continues to have catalytic properties of majors importances in cells, namely in ribosomes. Plus, there's the sheer scale. A mole of monomer precursors for all of these could be disolved in a modest quantity of water, maybe as little as 1 liter. Now, I've forgotten just how many atoms are in a mole, but it's Huge, something like 10^23 atoms. Now, multiple that by how many liters of water are in the ancient ocean. The chances of a single lottery ticket winning are infinitesimally tiny, but when you have 100 trillion tickets, you're pretty much guaranteed a win. Mokele Mokele

Hi, just thought I'd drop a note that I'm going to be visiting my GF in the UK for the next three weeks+, from the 19th to the 10th. They have internet (broadband, so better internet than me), so I'll still be able to check in, just not as often, as I'll be, erm, distracted. Anyhow, just letting you know I won't be around as often or posting as much. Mokele

Iirc, it was a very, very broad "phylogeny" (like lumping most european languages together), so the lamarkian effect would probably be minimized. I'll try to look up the reference tonight, but there's one small snafu: tommorrow at 7pm EST I fly to the UK for 3 weeks to visit my GF, leaving most of the references behind (including this one). I'll have a quickie look tonight while I'm packing, and if I can't find it, remind me on August 11th. It's not in a very specialist reference though, iirc. It was something more for the general audience (albeit not *everyone*, think of the sort of book you'd find in Barnes and Nobles' science section), and on evolution as a whole, so if I can't find it in time, google might work better until I get back. A part of me wants to say that it was "Evolution" by Zimmer, but I'm really not sure. I'll have a look when I can, though. But wouldn't that be mostly island-hopping down through Indonesia? And once humans became established on Papua / New Guinea, AU is just a short trip, iirc. Or at least relatively short. Now, the human colonization of Hawaii, *that* was a hell of a boat trip. Mokele

I know for my narrow range of interests, UC davis has a good herpetology program, and UC Berkely has a decent biomechanics program, though it's going downhill. Mokele

Well, first, apparently early dinosaurs like Herrasaurus have all 5 digits, though 4 was reduced and 5 was just a split. Even the primitive ceratosaurian theropods, including coelophysis, has a full 4. Only the more advanced species had 3. However, that said, there has been skepticism about the numbering of digits in birds, noted in an essay by G. Paul (http://www.dinosauria.com/jdp/archie/paulfed.html). I'm usually rather skeptical of his work, so I'd look into it more, but he does raise a valid point. This essay (http://www.biology.ualberta.ca/courses.hp/biol606/OldLecs/Lecture2K.04.Perry.html) also points out that the assignment of numbers to bird digits is problematic. Mokele

He asked about speciation, but the "no proof" is referring to the specific abiogenesis on this world. Mokele

Well, I tried to respond to what I percieved as his main point, about the factuality of evolution, but I came into the thread rather late, as I was on vacation. You can't prove diddly-squat in science above the level of raw data and observed pehnomena anyway. It's all induction and data analysis. I can't *prove* that the cycle duration for arboreal concertina locomotion is different between boas and corn snakes, but I *can* run enough experiments to say "there is a less than 1% chance that I'm wrong about this". And the problem is that creationism cannot be tested scientifically, while abiogenesis can. Not the *specific* one that lead to our life, as you point out, but the concept as a whole, and specific aspects of it. I cannot test "God made the first cell like this", but I *can* test "monelerite (sp?) clays which probably existed back then (see other paper blahblah) can provide a stable substrate for the assembly of complex polymers, including RNA." Technically, even if we do make life in the lab, it won't *prove* that's how it happened on earth. But it *will* make it more likely, and give us a starting point to work from, and which can be scientifically investigated further. However, it's all irrelevant, since, while creationism deals with abiogenesis, evolution does not. Evolution is a process that happens to life, not how it originated, much like gravity is a process that happens to mass, and does not dictate or care where that mass came from. In fact, they're so different that people working on one rarely have much contact with those working on the other, as each finds the detailed explanations of the other's work boring as hell (which I can personally attest to, no offense chemists). The main purpose of this thread, in my eyes, is a pressure release valve, a place to vent. Otherwise bad things* happen. Well, the thing is, you've got it backwards. The definition of "species" (though very, very highly contested due to the fact that evolution makes it a bit of a grey line) is contingent upon reproductive isolation in normal circumstances. Ideally, there should be little to no gene flow between the populations (like if all hybrids are sterile) for them to be species. Morphology is used because it's a) easier and b) can be done for dead things. The basic gist of speciation is this: 1) small group becomes isolated from the rest of the population (small groups evolve faster)(isolation is usually geographic of climatological) 2) small group is exposed to a different environment and different selective pressures, which cause them to evolve in a different way than the main population. 3) by the time the two groups re-unite, they've become so different that they can no longer interbreed. The problem is that we see organisms at *all* stages of the above. Some are both reproductively and morphologically distinct, some are just reproductively distinct (not enough time yet for major morphological change), some are just geographically isolated, and everything in between. This is why, on a mailing list I'm on, someone said that the best bloodsport in existence is locking a dozen biologists in a room an asking them to come up with an ironclad, universal definition of species. Life, as usual, does not fit into our neat little boxes. As for what we've observed, we've seen all of the above (geographic isolation, reproductive isolation, morphological/ecological change, and all grey areas). Given that we've seen animals becomes reproductively isolated, we say that we've seen speciation, as it's currently more-or-less defined. For several species of catus-dwelling fruit flies, we've seen basically the whole process, though the morphological change isn't huge in this case (it's more a change in ecology, with some minor morphology changes), but it's enough that, if we had's seen the process leading up to it, we'd've still said "oh, this one is a separate species from the other two". Plus, hell, they're flies, there's not much *there* to change. So we *have* observed the full process, but only in a very small animal with *very* short generation times. But there's no difference between a fruit fly and a blue whale as far why it shouldn't happen the same way. It's one of those questions where there is no simple answer. Since reproductive isolation is the *real* criterion, then we've seen speciation *loads* of times. We've also seen morphological changes (or other changes in phenotype) *loads* of times. The observing the entire process from start to finish, though, is more daunting, and could be seen as un-necessary, unless there are any major surprises for us in that (none yet, though). The short answer, though, is yes, we've seen what any rational observer would call speciation. Mokele * - Bad things involving the Institute for Creation Research and armies of cybernetically-enhanced atomic mutant gorillas, for instance.

I never did, and please show me where you think I did. Your reading of my post was evidently in error. There's a big difference between saying that life originated only once (which I also believe is unlikely) and that there is no single common ancestor. Imagine early earth, with lots of newly formed life, all different. But one is a bit better than the others at competing and evolving. Over time, it occupies more niches, gains more resources, and eventually drives the others into extinction. This life form (or the original one of that highly successful lineage) would be the single common ancestor of all life. Other forms of life also probably appeared, but are now gone. Saying that because life originated multiple times you cannot have a single common ancestor is like saying that snakes cannot all have arrisen from a single ancestral snake because there are numerous lineages of lizards. Ahh, I guess I'm not familiar with the term because it's worthless and doesn't describe a real phenomenon of any significance. Sure, all the populations are evolving, but unless the selective pressures are the same (which, given environmental heterogeneity, they are not likely to be), they will *diverge* (unless there is sufficient gene flow to erase the differences). As for one human within a population becoming the common ancestor, it's a fact. Google "Mitochondrial Eve" and "Y-chromosome Adam". You haven't kept up with even painfully obvious occurences in the field, and it shows. If you mean that gene flow will mitigate or erase the effects of selective pressure, yes, if there is enough of it. This also will cause a population to stagnate and go nowhere, evolutionarily speaking. The bigger a population, the longer it takes for a gene to reach fixation. Small populations evolve fast, simple as that. When you have a "super-population" composed of many populations linked by gene flow, you have a very large number of individuals, which is going to slow down the rate at which a gene moves to fixation. As a result, I find it *highly* unlikely, given how slowly our species reproduces, that such a large population could evolve into humans together as a whole. Again, your ignorance of modern research shows. This point has been explicitly disproven. I'll dig up the reference, if you want, when I get home. In fact, the "linguistic phylogeny" almost perfectly matches the "out-of-africa" dispersal pattern from a single human origin in Africa. Why not? Give me one good reason why not? Your "theory" requires gene flow, and guess what? If two groups are different species, *there is no significant gene flow* by definition. Yes, it happens once in a while, but by an large most species are significantly different enough that they are reproductively isolated. Give me one scrap of evidence that the selection pressures on H. Erectus in Kenya were the same as those in Java. Savannah and jungle. How can you *possibly* argue for similar selection pressures in the face of such environmental heterogeneity? On the contrary, there is *evidence* for a single common ancestor, both of humans and of all life. In contrast, I haven't seen a scrap of empirical evidence to support your theory. And without evidence, there is no science. I seriously suggest that you familiarize yourself with the current literature in this subject. This is *far* from my field of expertise (snake biomechanics and evolution), and yet I'm *still* easily dismantling your 'theory'. Talk.origins has a lovely FAQ on fossil hominds, if you want. Mokele

All of that is two points, one of which can easily be explained by the spottiness and poor preservation in the fossil record. Coeleophysis may well have had feathers or protofeathers, but we just never found one that died in a situation that would have led to the preservation of that feature. We're almost *definitely* missing a large chunk of early bird evolution, simply due to the fact they were small, and small animals (with delicate bones) don't preserve as well and are less likely to fossilize. As for the embryology, that really is a puzzler, no doubt, but given the masses of evidence *for* an avian origin, I suspect it's going to be sorted out when we figure out the "rules" and tendencies for how developmental patterns change in a macroevolutionary time scale. Mokele

Correct, and it has in numerous laboratory experiments. Also, RNA can fold an act as a catalyst, similar to a protien (but less efficient). Current theory is that the first steps towards life were self-replicating RNA catalysts. Indeed, it's entirely possible that the first organisms could have been based wholy off RNA, with the RNA fulfilling the role of both genetic material and biological catalyst. I'd love to hear how you concluded that. Just because we don't know precisely how it happened doesn't mean that it couldn't or was "comparable to impossible". That's like saying that just because we don't know how galaxies formed, their formation was next to impossible. Mokele

Oh *Hell* no. I'm referring to the original organism, the first microbe with DNA, etc. "Correct theories"? All you've mentioned is something called "parallel evolution", which I'm only familiar with as an archaic term for convergent evolution, in terms of the multiregionalist hypothesis of human origins. Then you said *something* about there not being a "single cell precursor to all life", which seems to have diddly-squat to do with this thread, since it deals with life as a whole, and the thread explicitly deals with human evolution. My reply was basically that I don't buy the multiregionalist hypothesis of human origins, and instead support the theory that all humans arose from a population of H. erectus that became isolated and exposed to different selective pressures, like how most species form. "Along the chemical pool"? What are you talking about? There are no "chemical pools" guiding the progress of evolution. DNA may contain the information, but evolution is ruled by phenotypes and their interactions with the biotic and abiotic environments. If your "parellel evolution" is the same as convergent evolution, then organisms evolve towards similar forms *only* under identical or near-identical selective pressures, in similar niches. Biblical whatever has no place in this thread, ever. It belongs in the Psuedoscience forum. That said, the problem is that you seem to never elucidate what you're talking about. First, you talk about human evolution, but then you make a claim about the ancestor of all life, completely out of the blue. Did you mean all *human* life? If so, that clears things up a bit. I'm not sure what you're refering to as "speculative theories"; the fact that all life on earth (human or otherwise) evolved from a common ancestor is well established and well-supported. Please, define your terms, since you seem to be using ones that don't correspond to a defintion I know, possibly due to a language barrier (guessing from your location). Mokele

I just downloaded it. PM me your Email addy and I'll forward it on to you as an attachment. Mokele

The simple problem is that there is *no* definition for consciousness that is even remotely useful or testable. Without even the basic definition of a concept which, frankly, I suspect is more a side-effect of a complex brain than an actual trait, there is no way to say diddly-squat about its evolution or lack thereof. Frankly, this whole thread sounds more like philosophy than science, with science mixed in. And the two don't mix well; most philosophers get things very badly wrong. A friend of mine, the head of the philosophy deptartment here, is famous for pissing in everyone's philosophical corn flakes because he has a strong background in neurobiology, and can thus blow their philosophies out of the water when they start talking about the mind. Mokele

If so, looks like yourdadonapogos was right about the award....