Mokele

Algae grow anywhere and everywhere, fresh and salt water, lakes, streams, everwhere. The problem is that dumping large amounts of nutrients into lakes via runoff leads to a huge increase in algae, which blocks out light to other water plants that fish and such eat. Then the algae die, and the decomposer bacteria use up all the oxygen, choking out the aquatic animals. It's not a case of 'nutrients are bad' so much as 'dumping too much of *anything* all at once into a system leads to disturbance of the balance'. Mokele

I dare you to tell the family of Matthew Shepard that's worse. Or to the family of any of the *hundreds* of people who've been killed for being different. As long as I'm alive, I can fight the problems of the party. The American Taliban would ensure that doesn't happen. For some of us, this isn't about ideology, it's about survival. Sorry, but if you're willing to support a hate-group just because the other side has some questionable politics, you shouldn't be voting.

Carol, that site is a hoax, utterly worthless creationist bullshit. A much better link, this one with real science: http://www.talkorigins.org/faqs/abioprob/

The Democrats weren't the ones actively campaigning on the platform that they should be able to fire me, evict me from my apartment, deny me loans, and deny me insurance because they don't like my sexuality (yes, that was the *literal* text of a law, passed by the American Taliban in Cincinnati, and only repealed recently amid much Dominionist opposition). They may not be perfect, but I wouldn't be afraid of a Democrat-controlled government setting up concentration camps. I can't say the same for the American Taliban and their ceaseless hatred for anyone who doesn't conform to their faith. I'd rather vote for a PC-stooge than someone with ideals on part with a Ku Klux Klan member. Mokele

Ok, potentially dumb question: Why doesn't friction involve surface area? Is the friction force on a 10kg object really the same whether the object's contact area is a square centimeter or a square meter? Mokele

The Urey-Miller experiment was in a strongly reducing environment, IIRC, with lots of amonia and suchlike, but new evidence suggests that ancient Earth's environment was more neutral or oxidizing. Of course, IIRC, people have repeated the experiment with numerous types of atmosphere and gotten the same or better results. IIRC, we've even gotten RNAs. Mokele

Dolphins only have front limbs; there's remnants of a pelvis, but aside from this individual, none with rear limbs. They are indeed modified legs: the front legs became flippers, while the rear ones were lost. Fish fins, however, are the same, since they're what limbs evolved from in the first place. Also, both have a tail. Oh, wait, I get it, you think the fins at the tip of a dolphin's tail are it's rear limbs, yes? That's not actually correct; the flukes are merely extensions of the tail, not modified limbs. Does that help clear things up? Mokele

Heart muscles, when developed, beat on their own. If you grow them in culture, the entire sheet of cells on the culture medium will twitch with a regular rythm. I suspect the first heart beat occurs when the development of enough muscle cells is complete to allow the twitches to synchronize and contract the whole organ. Mokele

However, given the way the politicians pander to the American Taliban, it really doesn't matter; they've insinuated themselves so deeply that I don't trust any elected Republican (or many moderate demoncrats) to be willing to offend them at the risk of their political careers. Mokele

Or maybe they're just educated / worldly enough to see the Christian Right as the hate-mongers they are?

We've got no objection to helping with your homework, but we're not going to do it for you. We may check your answers, or explain parts you're having difficulty with, though. Mokele

Good, that'll give permanent license revokation some teeth. If they get caught, they lose their license, forever. If that's an impediment, tough shit, they need to either learn to bike, or they need to move to a city with public transport. Yeah, that sucks, so does being killed by irresponsible drunk drivers. Hell, I'd even go so far as revoking their ability to collect welfare if they become jobless as a result of these restrictions. To be brutally honest, I think any drunk driving fatality should be *required* to be prosecuted as first-degree murder, with no option of parole or plea bargain. They chose to drink, they chose to drive, therefore they made the choice to kill another person. Mokele the Merciless

The correct term is "quack". Want to see why? Google image search "argyria". Yes, that's what happens if you use this colloidal silver BS: you turn BLUE! This is why one should trust *real* doctors instead. Mokele

Ok, from how I understand it, bananas were selectively bred extensively when they *had* seeds for things like size, smaller seeds, flavor, etc. Plant chromosome number is pretty malleable; they get by with losses, gains, even total duplications (the common strawberry is Octoploid, IIRC). But if a polyploid (diploid rather than haploid) pollen hits a normal ovary (haploid), you get a triploid, whose chromosomes can't segregate properly, and thus never makes seeds. So, on one hand, there *was* selective breeding of bananas prior to seedlessness, but on the other a *common* meiosis error (well, common in plants) is likely what produced the seedless varieties. Honestly, with so many banana plants, I wouldn't be surprised if seedlessness cropped up dozens of times. Mokele

Xavier: you give a plausible guess at the evolutionary reason behind the differences (though I should note that human net cost of transport is the same as a chimp, and that early humans were more likely to be scavengers than hunters, at least until we made tools), but that still leaves open the issue of mechanism. What matters for precision isn't the muscle size, but the number of motor units. Muscles don't contract as one. If they did, you couldn't modulate force. Instead, they have 'motor units', groups of muscle cells innervated by the same nerve. If a muscle had only two motor units, it would have only two 'settings': full force and half force - either one set of cells is active, or both are. Now, when humans increase muscle cell development (since you always have the same number of muscel cells, just bigger ones if you work out), that means each motor unit generates more force, and gives a 'coarser resolution' to muscle force development. Similarly, if humans have the same number of motor units as a chimp (I have no idea if this is true or not), but each unit produces less force (and thus less total muscle force when all are active), we'd have higher precision. Mokele

The pelvis That's a drawing, and a bad one at that. Googel image search "Dolphin pelvis". It turns up 27 pages of results. There are no genes for arms or legs. Just genes governing bone formation, the formation of limb buds, etc. What determines if limbs form or not is whether these genes are turned on in the right sequence. Some genes make structural protiens and the like, but many others govern what goes where, and most of the genes and regulatory DNA segments are involved in that. Organisms are only made of a few different things; what's important is when and where those materials are laid down and how they're shaped through development. Remember, dolphins already have forelimbs, along with hindlimb vestiges. That means they've got the construction materials, and the developmental tools. On top of that, they develop limb-buds early in development, but the rear ones are terminated. All that needs to happen is for that termination to malfunction, and a good portion of limb development will proceed automatically. If you think this is implausible, google scholar "talpid-2" and "chicken". Chickens with *teeth*. Real teeth. And it gets better: the developmental pattern of these teeth is archosaurian, the same pattern of crocs and, presumably, dinosaurs. Mokele

You need a second mutation whose location is known. For example, if you know "leggy" is on chromosome one, you can see if "black" co-occurs with leggy more often than chance, and if so, they're on the same chromosome. It's not possible with just one gene; you need more. Mokele

I think you need to specify which STDs. Some, the big nasty ones like HIV, gonorhea, herpes, etc, need sexual contact, and a condom will work. Others, like HPV and crabs, can be spread by simple non-penetrative contact. Obviously the former will be much more impeded by a condom than the latter. Also, look into oral versus anal and vaginal sex. Sadly, a lot of people who use a condom during the latter two don't for the former, and you *can* get STDs via oral sex. Mokele

Not quite. Mutations occur randomly and constantly, but also a *lot* more often than most people realize. Statistically, I can assert that you, personally, have 4 mutations that affect final protien structure. It's not so much that the needed mutations happens at the right time as the idea that if you keep playing poker, one day, you'll draw a straight flush. A population of hundreds of thousands of organisms, each with several mutations, is equivalent to drawing 400,000 poker hands: statistically, there's a good chance that there's a very good hand amid all that crap. Sort of. You need a structure in order for a function to happen, but a function can already happen and just be improved by a change in function. For instance, animal A runs, and the legs already fill that function, but slightly longer legs improve that function. Actually, no, I just didn't mention it because it's pretty common in bird. All mammals have 7 cervical vertebrae (except sloths and manatees), and all the different mammal necks are made by modifying those 7. This is actually very odd; birds, reptiles and amphibians all have tremendous variability in neck vertebrae. So actually, I suspect it's a pretty fair bet that flamingo necks are modified. Don't be fooled by the long legs. Long legs may have evolved *after* filter-feeding, as they have repeatedly evolved in different lineages. We actually don't know what flamingos came from; the fossil record is very spotty in that regard. Bingo. Many complex traits are really just the end result of a series of steps. Mokele

Thanks very much! Now, to teach myself enough electronics to actually be able to improve my experimental equipment....or I'll just suggest it to various vendors at this year's SICB meeting and let them deal with it. Mokele

Sorry, but no. I know it's cliche, but guns don't do squat without a person behind them. As for the numbers, what are they per-capita? And what are the *total* homicide rates for each country, including attempted homicides? How much of that drastic difference is merely a shift in preferred/availible weapons? If the latter, people aren't safer, just being killed by more non-gun means. Mokele

It's often hard to understand the evolution of a specialist on it's own. It helps to look around at species in the same broad taxonomic group that may have part or all of the adaptations seen in the specialist. For instance, consider ducks. Many are dredgers and detritivores, feeding on small animals, soft water plants, and algae. Some have ridges on their bills to help strip plant matter. Some others have actually developed these ridges to the point they can filter-feed a bit, but nowhere near as well as flamingos. It's actually not that hard to imagine that a shore-dwelling bird feeding on vegetation evolved ridges to strip plant matter, then used them for floating algae, then suspended particles (each time, the filter mechanism becoming more advanced). Long legs evolved to allow them to reach deeper waters, with the commensurate long neck for reaching the water in the shallows. As for being upside-down, it's not that much of a stretch; many animals with long necks could be said to do the same thing when feeding from the ground, if you think about it. It's also worth noting they aren't the first. Pterodaustro as an ancient pterosaur (flying reptile) with a 5-foot wingspan which developed a mouth full of bristles to filter-feed. It's even suspected that, since it feeds like flamingos, and they get their color from their food, this pterosaur may have been pink! Mokele

Aside from chemotherapy and UVB for rickets? This is actually juse due to bone growth. As kids grow up, their ear bones become larger,and transmit lower-frequencies. We can actually figure out a rough idea of the hearing range of extinct species based on their ear bones. No idea why that's the case of asthmatics, though. More likely it's due to mucus clogging various ear tubes or infection-induced alterations in the viscosity of the cochlear fluid. Extremely unlikely, with the exception of vitamin A deficiency (the precursor to retinol). Basically, photo-sensitive cells have a chemical, retinol, which reacts when hit with a photon. The protiens holding retinol are what determines the frequency it responds to, along with colored oil droplets in the cells of some animal eyes. If an infection affected any of these, you'd be dead long before you saw the difference. Mokele

If you have a pure homozygote dominant crossed with a pure homozygote recessive, it'll be het for both genes, yes. I think the thing is that your instructor didn't want the full punnett square, but rather for you to simply say that all the offspring would be RrBb. Unless there's some aspect of the question you've not told us. Mokele

Standard error is just standard deviation over the square root of sample size. If you want one of 2, with a standard deviation of 5, just plug it in: 2 = 5 / (n)^1/2 The rest is just for show, and gives you the 95% confidence interval you'd get from that standard error.