Mokele

Awww, I feel so loved! Anyhow, what it boils down to is how to classify things as a whole. Some argue that all organisms with a certain common ancestor (a "clade") must be grouped as one, thus making birds a part of reptilia. Others argue that if one branch of the clade is sufficiently different, then it is justifiable to give it a separate classification (in which case birds would not be reptiles). Of course, this gets even *more* complicated when you take extinct species into account. It's easy to argue that birds are different enough to be separate based on modern animals, but much harder when presented with numerous fossils that seem to be somewhere between bird and dinosaur. Where does one draw the line? Should one draw any line at all, or should it be cladistic (the first of the two approaches I mentioned). Currently cladistics is gaining popularity, but not without controversy. The problem is that taxonomy itself is a junction between science and language, since it was invented as a way to talk about species and groups of species. The former is all about logic, rules, evidence, evolutionary history, etc, while the latter is more fluid, intuitive, arbitrary and immediate. That's not saying one is better, just that the two work in different ways, and how we think is not always how we speak. Basically, cladistics (which says birds are a type of reptile) is more scientifically accurate, but is more cumbersome, difficult to use, and impedes the primary purpose of taxonomy, which is communication. On the other hand, phenetics (which separates birds and reptiles) is more intuitive, easier to communicate, but is often very wrong and fosters misunderstandings which have to be corrected (a process that itself weighs down and impedes communication). So the best answer is that birds evolved from dinosaurs, which evolved from archosaurs, which evolved from reptiles. To what extent which or any of these groups is within class Reptilia is highly dependent upon one's perspective and position. In essence, it's an issue of "how do we draw the lines?", which is complicated by linguistics and the fact that, frankly, the lines are pretty much just arbitrary concepts for our benefit anyway. Mokele

While this may be too much information, I can definitely say that lack of circumcision does not necessarily lead to any negative health effects. I can see how it might be a problem for those with poor hygine, but if your hygine is *that* bad, you have other problems to worry about. Plus, well, think of it like this: for 250,000+ years, human males have had foreskins, and they did just fine. I'm highly skeptical that the environment has actually changed in a way that would make a formerly positive attribute negative. Mokele

From the above website, peak density seems to be about 175,000/mm. But light has to pass through the lens, so I'm not sure how that translates into whether we can distinguish pixels or the like at a certain distance. I never was very good at Optics. Mokele

The problem is that, without a testable definition of "emotion" that lacks all these annoying grey areas, there's no real way to tell. Is hunger an emotion? What about lust? Both are just hormone-based responses. Is my lust homologous to the lust a beetle feels? What about something more complex, like feelings of accomplishment? How, exactly can you test for that? I mean, we can be pretty sure sponges lack emotion, since they don't even have nerves, and that we do have emotion, since we made the term up. Beyond that, we're pretty much just guessing until someone comes up with a testable definition of "emotion". Mokele

The photon knocks a high-energy electron off a magnesium (iirc) atom, and the electron is passed to various protiens (which have some other form of metal in them, often iron), generating ATP as the electron's energy is lost. Given that ATP is pretty much the universal currency for cellular energy (though other chemicals are also used, such as GTP and NADH), I'd say that yes, a plant is definitely directly taking in energy (the photon) and pumping out cellular energy. Mokele

Well, I don't think it was *the* last, since at any given time there were usually multiple species of pterosaurs in a range of sizes and niches, but, IIRC, it was the last of the truly big ones, and lived right up until the very end. Mokele

Awww, and I was hoping he'd get to see his idea's death. Somehow, I don't think I'll miss him. Mokele

........... .................... That is the stupidest extinction theory I have ever heard. It's based on *art* not evidence. Let's see what the real evidence has to say. You do realize that most pterosaurs (giants aside) were approximately seagull-sized, and actually weighed about the same? Hollow bones, sometimes nearly paper-thin. Furthermore, there are flying birds both before and after the KT boundary. If there was a gravity increase, we should see different anatomy in the pre- and post- extinction groups (lighter bones, smaller size, etc). We see nothing of the sort. We similarly see no major alterations in flying insects. Aside from the fact that only a few, straggling families of sauropods were even left by the late cretaceous (most had been out-competed by hadrosaurs and other ornithischian grazers), there is similarly little evidence for this as a reason of death. Currently, the main theory on diplodocid biomechanics is that, like gap-bridging snakes, they possessed extremely long tendons that anchored the neck to the spine. They had similar anchors in their tail, which served as a counterbalance. There was little, if any, muscular force involved in holding the neck in position. And, by the way, the average diplodocid sauropod's head was less than 12 feet above the ground. Most of the very-long-necked ones held their necks horizontal, not vertical. Once again, your idea is flatly wrong. 1) Alligators can *still* gallop and walk erect 2) Genus Alligator (yeah, creative name, huh?) exists on *both* sides of the KT boundary, with NO evidence of anatomical modifications. Ditto for crocodiles. Now, the real killer for your idea: 3) Ziphosuchians, the erect-walking crocodylians I spoke of earlier, existed *AFTER* the dinosaurs died. In fact, they enjoyed *much* sucess throughout the world until fairly recently (likely due to climate change). However, there are *also* erect-walking crocodylians from long before the dinosaurs, the sphenosuchians, *and* a group of erect walking archosaurs somewhat closer to (but still before) the dinosaurs, the Erythrosuchids. The former are small sprinters, so don't make a good comparison, but the latter are the spitting image of the post-extinction Ziphosuchians. And they display *no* differences that would indicate a gravity shift. Snakes *did* have legs at one point. But they lost them 120 mya, almost 60 million years *before* the KT extinction. Things we would recoginze as modern snakes existed 90 mya, 25 million years *before* the extinction. Or were they just really good at anticipating things? Turtles have been around for 200 million years. They have *always* been primarily aquatic. And the largest land-living form, roughly the size of VW beetle, not only lived *after* the extinction, but was killed off by *humans*. And you didn't read that article, nor do you have any significant knowledge of paleobiology. Want to know how I can say that? Aside from the massive evidence of your ignorance displayed above? Whales lost their limbs *AFTER* the KT extinction. A very Long time after it. Whales evolved from Mesonychids, a group of *erect-walking* mammal predators that looked like wolves, but were closer to sheep in ancerstry. We have a long and beautiful sequence of whale fossils showing the transition from one to the other. All of it is *after* your proposed gravity increase. So, let me get this straight: mammals lived through the KT extinction, into your "high gravity" world, but *still* evolved an upright stance, and then said "Oy, 25 million years of standing up is tiring, let's go back to the water"? Your theory displays nothing but the most superficial and trivial understanding of paleontology. Your grade: F Mokele

Technically, the human population is evolving every day. Evolution = change in allele frequency in a population over time. Every time a new individual is added to a population (by birth or immigration) or an existing individual is removed from a population (by death or emigration), the gene frequency changes. Now, for most genes, most of the time, this basically balances out and there's no long term change. However, if there is a continuous selective pressure, there can be change in both the short and long term. How fast any change can occur depends on two things: size of the population and selective pressure. If we had a small population of humans under intense selection pressure, evolution would proceed very fast. For a large population (like now), selective pressure would have to be large to produce any sort of advantage at all. Anyhow, for direct evidence that humans *have* evolved since the agricultural revolution, look at our CCR5 receptors. Currently, they're used by HIV, but some individuals lack them, making them very resistant to most HIV infections. Why? Because a bacteria (Yersinia pestis) used that same receptor to impose strong selective pressure about 800 years ago. The selective pressure is more commonly called The Black Death. Individuals who lacked the receptor were immune, so their genes propagated the most. Even now, centuries after the Plague, we still see large numbers of people carrying the genes for faulty CCR5s in Europe, where the plague was worst. So there's empirical proof that humans *can* and *do* evolve on a shorter time scale. Mokele

Ophi's right, the Dems have been using the spectre of the draft as a scare tactic to try to galvanize opposition to the war. It's not realistic, imho. Actually, they probably wouldn't, on account of never having finished training. That's one of the reasons cited why a draft is unlikely: it takes so long to train a modern soldier to be able to do their job that a draft would basically be a waste of money and time, since you'd *never* get most people trained before their enlistment is up. Well, patriotism aside, there's the feeling on this particular war. For instance, I love the US, but I think this war is unjustified. I see a great difference between defending my country and this blood-for-oil exchange. Mokele

"To surrender to ignorance and call it God is, and always has been, premature" - Isaac Asimov Just because we don't know why it happens *now* doesn't mean there isn't a scientific solution, only that we don't know it yet due to limitations in tools or knowledge. Science is always a work in progress. Mokele

Google it

1) I'm not convinced that such a fossil trackway exists. If you're referring to the trackway in which we observe an acrocanthosaur killing a large sauropod, the "hop" mentioned in the popular press is *not* what is kinematically classified as a "hop", but is merely a perfectly ordinary gait change. 2) I'm not arguing that dinosaurs could not hop, or never hopped, only that it was not their primary mode of rapid locomotion. We can hop too, but we don't when faced with a threat, because running is far more efficient and faster for us. Because it's the ancestral state. For them, it remains useful. While their stance limits endurance for reasons already mentioned above, it does not limit burst speed nor is it actually any less efficient. For small animals who do not need endurance-based escapes, this is fine, and may actually be preferable, as it allows them to fit into hiding spaces not availible to erect-walkers. Erect walking only makes sense in a narrow set of conditions, which is for an organism which can profit from high endurance enough to justify the resultant required increase in basal metabolism. Your maximum endurance is always roughly 10x your basal metabolism. So if an animal gains the ability to run at faster sustainable speeds, it pays the cost of having to fuel that higher metabolism 24/7. For many animals, the cost just isn't worth it. Evidently, for primitive mammals and archosaurs, it was worth it. Mokele

New Orleans for a long weekend, England for 3 weeks to visit my GF, and Guam for 2 weeks doing fieldwork. Mokele

Agreed. I, for one, am more than a bit disquieted by how readily people assume he is automatically guilty just because he is weird. Yes, some of his behaviors set off alarm bells, but these behaviors are *correlates*, not perfect indicators. If Bob regularly uses PCP, and suddenly someone he knows is murdered, does that mean Bob definitely did it? No. Bod certainly *may* have done it, and he should be at the top of the list of suspects, but without any further evidence you cannot and should not convict him. Being rather weird in both personality and appearance myself, I'm more than a little uneasy about how quickly people jump to conclusions based on superficial evidence and mere correlates. Mokele

Well, there's two reasons for anything, proximate and ultimate. The proximate is why is smells good at a chemical level, in terms of how we smell and how this particular smell triggers pleasure. The ultimate is why, in an evolutionary sense, do we have a positive perception of this smell versus, say, rotten meat. In terms of proximate, perhaps the smell is a chemical that's not normally volatile alone, but can be carried into the air by microscopic drops of evaporating water? As for ultimate, it's pretty simple, IMHO: Our ancestors were foragers, and after the rain all sorts of stuff comes out and starts moving around, where we can find it. I know for reptiles and amphibians that after a rainstorm is the best time to go field collecting, and I suspect the same is true for many other species, too. Thus, the smell of rain is associated with a food bonanza. Mokele

I call BS on the "no brain" bit. No brain = no respiration = dead. Mokele

AFAIK< it's so probable that it's pretty much definite. Especially since the only way to get a phylogeny of HIV viri to make any sense is to include several forms of SIV. Basically, we know HIV came from SIV. Given that SIV, being "simian immunodeficiency virus", is present in monkeys, it's a pretty fair bet that HIV came from SIV making the crossover. Mokele

Nope, it's actually sudden growth/expansion, which utilizes change in water levels somehow (I dunno, I just grow em, I don't sutdy them). It was actually only just figured out recently. Each time the trap opens and closes, the cells get bigger. Mokele

You mean aside from the total lack of an anatomical feature that is necessary to make hopping energeticly worthwhile? 1) I'd like to see a source for that. 2) Did the trackway show actual hopping, or just convince people that maybe they could, at some point, hop? We have trackways that prove dinosaurs could run, when they remained below a certain size (just like how modern elephants can't run). Technically they probably could hop, of course, but not as a primary mode of locomotion for extended distances like kangaroos do. Also, it should be noticed that the only "hopper" large than a rabbit is a kangaroo, and the only reason they hop is because that's the only mode of fast locomotion availible to them. They cannot evolve the specializations needed for fast, quadrupedal running because, as marsupials, they need dextrous forelimbs to move into the mother's pouch. It is *a* difference, but certainly not the biggest. Other differences, such as hepatic piston respiration, the 4-chambered heart, skull morphology, feathers, and possibly endothermy, would all be "bigger" differences. I could quibble the with the snakes on the ground bit by pointing you to the recent series of papers in the Journal of Experimental Biology on Chrysopelea genus, the gliding tree snakes, but I won't. I will, however, note that not only does posture become more erect with size (in both mammals and reptiles), but that modern crocodilians technically are half-erect. Look at the back legs during a high-walk: they're straight up and down, like a mammal's, even though the front limbs are only semi-erect. Modern crocodilians (alligators, caimans, crocs and gharials) evolved from the Sphenosuchians, a clade of archosaurs that looked, for all the world, like reptilian greyhounds. They were about the same size, similarly sleek, and had long, upright legs. The modern condition of crocodilians is a secondary reversion to the sprawling state, an adaptation for their unique lifestyle as shoreline hunters. Every time they've left that niche for land, erect walking has returned. However, what reptilian and dinosaurian locomotion has to do with the KT extinction is beyond me. Mokele

Both crocs and dinos are archosaurs (as are birds, technically), but crocs are not dinos, while birds are. More or less. While, AFAIK, no lizard has ever achieved a fully errect gait, the first crocodylians actually resembled reptilian greyhounds (small, fast, erect-running). While the main line of crocodylian evolution has been the form we all see today, there have been numerous returns to fully-upright posture among prehistoric crocs. And the hip socket is more of a consequence than a cause. Basically, lizards don't have a diaphragm, and use contractions of the rib muscles to breathe (along with buccal pumping, involving the floor of the mouth). But they also use those muscles for locomotion, setting up a conflict of interest: any locomotion requiring lateral flexion of the body (which is basically everything above a slow crawl for sprawling animals) makes breathing impossible. This is why lizards run a short distance, stop, run, stop, etc. If they run continuously, they exhaust themselves. Erect posture solves this problem: it allows the animal to run and breathe at the same time. This, in turn, makes higher aerobic scope (range of sustainible speeds) a possibility, which comes from higher metabolism, which leads to endothermy. Seems good, but the conclusion (hopping dinos) is dead wrong, and based on some flawed assumptions (limited lateral and torsional motion of the femur prevents fast running? Has that guy ever seen an ostrich?). It's also contradicted by fossil evidence: hopping is pretty damn crappy as far as locomotion *unless* there's an elastic ligament involved. This ligament is present in all hoppers today (and actually makes them even more efficient than runners) and leaves *very* obvious signs on a skeleton (namely the attachment point), which I have seen in precisely 0 theropod skeletons to date. Mokele

That automatically rasies the question of "Why?" Why would a group of animals that has been spectacularly sucessful for so long sudden begin to "over-eat"? From what I've been able to gather, there was a lot of stuff happening at the time, especially climate change. Nothing alone would have killed them, but the meteor hit at *just* the wrong time, delivering a knockout blow, so to speak. Mokele

Well, I know a while back Ophiolite and I kicked around metabolic rates of dinosaurs (warm, cold, or in between?) and the possibility of a future debate was mentioned, but the problem is that my position is very "middle ground". Then again, I could argue for a position I don't really support, as he surely could, giving us a bit of an artifical polarization. Mokele

As far as I understand, most of the opposition is based on the arguement that birds arose from another small, arboreal non-dinosaurian archosaur. Given than, AFIAK, there is no record of such an organism nor any lineage even close, and it would have to display a ridiculous number of improbable convergences, I suspect it's pretty much just arguing for the sake of arguing, with little real support. Mokele

I think numerous racoons, squirrels, possums and armadillos can attest that life in less than 3 dimensions doesn't work very well, at least when one has to undergo a rapid conversion from 3D to 2D. ;-) Mokele