Paralith

well...it is different proteins joining together to form a large unit. It can be multiple copies of one amino acid sequence, aka multiple identical proteins joining together, or it can be multiple but different proteins joining together. The point is that if and how they join together depends on each individual protein's shape; a shape that is determined by that individual protein's amino acid structure. Please let me know if you're still confused.

you basically have it. quaternary structure is when multiple amino acid chains come together to form a super-structure, so how they fit together is determined by each individual chain's tertiary structure. In the end, it's still ultimately caused by the amino acid sequence.

I think the desire to not inflict violence or pain on animals is basically an extrapolation of the fact that we humans ourselves don't like experiencing pain. Through our intelligence and our empathy, two other evolved characteristics, when we see other animals experiencing what we would experience as painful, we can imagine the feeling, and we don't like it. And yet we also evolved to enjoy eating the meat of other animals - it's a richer, more efficient food source, so to have a taste for it is evolutionarily advantageous. By both eating meat and being as human as possible with our food animals, we can get the best of both worlds.

I personally don't see what's so mortifying about not knowing how to use a pipette or pipet-aid because you've never had to before. It's not a very complicated thing to learn. When I got my first job as a research assistant during my junior year of undergrad, I most certainly hadn't done any of those things before (it had taken me a while to settle on biology as a major, so I hadn't taken a lot of practical labs) - but neither did it take much effort to learn them. And even from that first list, until I got my current job, I didn't even know what a hemacytometer was. But with about 1 minute's worth of someone showing me how to use it, I was fine. Also, temp lab jobs? I tried to find such a thing, but had no luck whatsoever. And somehow I don't think a temp-er would get a lot of training, anyway. I do think that undergrad education should try to be a little more hands-on when it comes to lab work, but the fact of the matter is that a decent amount of people fresh out of undergrad will have to be taught some specific skills on the job, even if that job is just volunteering in a research lab at their alma mater. You have to start somewhere.

You definitely bring up a good point in that the danger of using too much math can be to loose track of the actual physical mechanisms going on. Though judging by the aversion to math most biologists here have mentioned, I don't think any of us are in danger of using it too much. ;P Seriously though, mathematical models can still be powerful tools, as long as they are used properly. The relationship of the variables to actual, physical phenomenon has to be well understood in order to be accurately applied. If you're trying to understand the effect of a complex system - say, how weather patterns affect the population demographics of a certain species of animal - there can be so many factors involved that it becomes difficult to visualize it ourselves. This is where mathematical models can help us, but again, as long as the variables are accurately mapped to the environmental factors they represent - which in itself can become a whole research project.

You give me too much credit, CharonY. It was Phil, not I, who listed the above points as you see them, though I do for the most part agree with them. Point number 2 I agree with completely - I myself am pretty guilty of it. I'm not very good at math, and I most certainly don't enjoy it. Despite that, though, I knew that I would really need it, and voluntarily took a research statistics course (that was not required for my major) in undergrad. And I was really glad I did - it helped that the teacher was excellent, and illustrated every point with a practical example taken from real, natural science research. In fact, I would have taken a second semester with her had my schedule permitted it. I think I would combine points 1 and 3 into the fact that simply getting into the field of biology requires a that a very broad knowledge base be established first - even so you can decide where in biology you want to specialize, if nothing else. I think that problem is just that the field of biology is so huge - a bio 101 class will only briefly touch on the surface of all the subjects it tries to cover. Even the specific field of ecology is also very broad, and again, an ecology 101 class will only be able to go into so much detail if they want to achieve good coverage of the field as a whole. Thus why it seems that these classes are relatively easy - it's because they are. And I'm honestly not sure of a good way around it, especially since it's pretty universal to require the broader, more general classes before you can get to the upper level, more detailed ones, where the science really does get challenging. And in comparison to engineers, biology students spend less time in that zone of challenge while they're in school, because they spent so much time covering the basics. We're not saying that biology isn't rigorous. We're saying that the training of its practitioners isn't as rigorous, which is detrimental to the functioning of the field.

No, though the current state of drugs makes it livable. There are, however, some people - well, very very few people, I should say (don't get your hopes up, everybody) - who aren't susceptible to it because they have a genetic mutation causing their cells to lack the protein that the HIV virus attaches to. Which is pretty nifty.

Ouch. I hope I don't really sound that cold. I just honestly believe that if every single pit bull owner was a capable, responsible one, there simply would be no attacks. But that is not the case. And I've said before that I can understand banning a breed in general because of the cost and effort it would take to safely ensure every owner is a good owner and that attitudes about pit bulls are changed. Like people have been saying, when it comes to regulating things that are dangerous to humans, there are lot bigger things to worry about than dogs.

DrDNA himself said that some of his engineering acquaintances did meet with success in the field of biology. We're not saying it's not possible - just that many of them have trouble adjusting. I agree that their training is better only in that it is more rigorous, which I do think that biology training should be.

the point is that a good dog owner stops the dog before the mauling ever takes place. a dog that is allowed to maul is clearly not under it's owner's control, and, as you say, will not simply stop if asked nicely. I think using people as an example works against you. People are a lot more plastic than dogs. The difference is that people are a lot less inclined to change just because someone else is telling them too. A dog is much more willing and able in this respect. once a dog is well enough trained the owner doesn't have to be present 100% of the time. Dogs descended from territorial animals, and an ill-trained dog that thinks he's the boss will defend what he thinks is his territory. Yet a border collie can still be kept happily in an urban setting if given the right amount of exersize and allowed to expend their natural energy in a controlled manner. The same goes for a pit bull. If a pit bull is kept pent up, it will become frustrated like any other dog will, and being a pit bull it is more likely to express that frustration in the form of aggression, whereas maybe other dogs will do that zany spinning in circles thing, or just bark like crazy. I'm not trying to say that pit bulls aren't aggressive. They most certainly can be, but they are just as capable of being safely trained and controlled, and like we agreed, most pit bull owners just aren't that responsible. And if you own a powerful dog like a pit bull, or a rotweiler, etc, you have to be responsible for it.

They are also still dogs, which have been bred for thousands of years to listen to a human as an authority figure. "a caring and loving home" does not an obedient dog make. Pit bulls are strong, aggressive animals able to do serious damage to people with much less effort than a smaller, weaker dog. What makes a pit bull obedient and less aggressive is not hugs and kisses, but consistent and confident handling. Even the most loving owners can let their dogs walk all over them, and will be unable to control their dogs when they decide to be aggressive. A well owned dog doesn't make it's own decision to be aggressive, it looks to it's authority - the human. With proper handling, a pit bull is safe. With slightly improper handling, a pit bull is capable of doing great harm. A pit bull most certainly requires a very capable owner, and unfortunately, the majority of people who want pit bulls are not.

It was a college class - Vertebrate Anatomy and Phylogeny. I never learned so much in one semester. The lab portion consisted of these dissections, though I think my lab teacher didn't go as much into the evolutionary relationships as the other lab teachers did. Still, I learned a lot.

The "bodily harm" bias definitely skews the data if you're trying to accurately represent dog aggression towards humans; but the issue at hand is not dog aggression in general, but dog aggression that significantly endangers human safety. As an analogy, let's compare ping pong and baseball. Both sports involve balls coming straight at you at high speeds. But only baseball players are required to wear helmets. The overall number of ball-person collisions is probably very similar, but a baseball can really injure you, so action has to be taken to prevent that injury. Going back to dogs, if you're trying to decide what dogs are more likely to seriously hurt a person, then it makes sense to only look at instances of dog attacks where serious harm was incurred.

Not of the top of my head, and rather than have me search for you, head on over to this web site: http://www.ncbi.nlm.nih.gov/sites/entrez That should help you find some good papers. I'm sure there are lots from the people who did the human genome project and things like that. I usually work with specific genes, myself.

Well, unless you're looking for mutations in a specific gene, you're going to have to sequence the whole genome of your bacteria before and after UVC irradation and compare the two. You'll probably also have to do some calculation to take into account the natural rate of mutation as well.

if possible, a few rounds of dissections where you compare homologous structures in different animals would be interesting. and you could show how the structures were specialized for each given animal's lifestyle.

Yes, they attack more than other breeds. but what we're arguing is why. You say it's because they're simply inherently too aggressive and it doesn't matter who has them or how they're owned, and so they just shouldn't be allowed near people. I agree that they attack more often, but for different reasons. I think changing attitudes about pit bulls and more education about how to properly handle them would be fairer to the dogs themselves, but if it's easier for the NZ gov't to just ban the breed instead, then that was their choice. I definitely agree. People who want nasty mean dogs will get pit bulls and allow them to be mean and nasty. The only trouble with any kind of licensure will be the difficulty in enforcing it, and whether or not a given gov't wants to spend money on something like that.

There is an alternative explanation for the increased number of pit bull attacks other than their being innately more dangerous than other dogs, which I mentioned before but no one seemed to pay attention to, haha. Probably because it's not much more than my own conjecture, but I'll say it again. Once pit bulls had an established reputation as being good fighting/guard dogs, people who want mean aggressive dogs get pit bulls and raise them that way; people are afraid of pit bulls before they even get a chance to know the individual animal, and immediately show signs of fear and/or running away, inciting dominant aggressive behavior in the dog. Even well behaved dogs can go a little bonkers when they see something running away from them, and may react "seemingly without warning." Predators react to prey-like behavior. And as DrDNA said, reading the signs of this behavior ahead of time are hampered by the cutting of the dogs' tails, which most certainly isn't the dog's fault. Combine this with ignorant owners who aren't careful with their dogs and you get pit bulls being the center of more dog attacks than other breeds. I wold say that until you can show that this alternative possibility is false, then you can't be sure that innate aggression is the sole cause of the increase in statistics. Like INow said, correlation is not necessarily causation.

Stop right there. Yes. One diploid cell doubles it's chromosomes, then splits, and then splits again immediately, resulting in four haploid gametes. 2 will have the x, 2 will have the y. That's all the different "types" of sperm there are. And, while I'm at it, male differentiation begins at about 10 days post coitus, when the SRY gene on the Y chromosome begins to express, leading to the development of the urogenital ridge into testes, from which the rest of male differentiation results via hormones. As a woman, I think it goes without saying I personally dislike the idea that I'm incapable of being a genius. I'll be the first to admit that there are definitely inherent differences between males and females that aren't affected by the environment, but I still would like to see more data on this intelligence thing before I'll accept it. The definition of intelligence and genius themselves are still under debate as it is. Though I do think the distribution is interesting, as that's often what male to female reproductive success distributions look like. Take chimps, for example. There are the chimps that make it to the top and hog all the matings, and the chimps that are the losers and get practically none. But, every female in the troop gets her fair share of matings with the top male. This is largely why males are more willing to take risks when it comes to anything related to reproduction - they have a lot more to gain and a lot more to lose than females do.

Agreed. Just as any pit bull can be gentle, so can any other breed of dog become dangerously aggressive outside of proper ownership. However, because a pit bull is a large, strong dog that has been bred to be able to lock it's jaw on things it's been told to bite, then perhaps a pit bull's aggression may be more likely to fatally hurt someone than, say, a chihuahua's aggression. I can accept that. But other big dogs like rotties and german shepherds are probably just as able to seriously hurt someone. I think another reason that pit bulls seem so dangerous compared to other dogs is in fact their reputation. And because they have a reputation, ignorant people who want nasty fighting or guard dogs get pit bulls more than other dogs and then train them that way, further reinforcing the bad reputation. I think it's also very likely that people get bit more by pit bulls because they are more likely to be afraid of a pit bull. If your first reaction to a dog is that of fear and running away, the dog is going to pick up on that and is more likely to respond in a dominant, aggressive manner. And yes, this is very much off the topic of livestock treatment. But hey, at least we're talking about pit bulls and fighting dogs, which relates to the ultimate origin of the thread, the Vick case. *shrugs*

Daphniadance - a lot of the things you're mentioning as proof against rape as a means of procreation are artifacts of modern times, and were not in play at the time rape as an alternative mating strategy may have evolved - such as rapists wearing condoms. Condoms have only been at play for what - a hundred years? The mechanisms of behavioral expression are complex, and usually manifest as a tendencies or urges, not well thought out, conscious efforts by the individual organism. A rapist isn't thinking, "Well, gosh, I'm such a weirdo asshole that I can't attract females, so I'm going to go out and rape a few, that way I'll spread my seed!" A rapist would feel emotions and urges to behave sexually violently toward other females, which, back before there were condoms, would have worked just fine. Also, the reason why there weren't a lot of statistics in there (besides the 1 in 10 children raised by non-biological fathers, which the vlogger and blue_cristal seem to like to repeat), is because there haven't been too many - if any, really - studies done on the genetics of human rape. We're still not sure to what degree the tendency to rape is genetic, and if that tendency would vary between individuals. It's also important to remember that when you're talking about human behavior, and indeed the behavior of many socially complex animals, that we can really only speak in averages and trends. What a given individual decides to do over the course of their life will vary considerably with their genes and the specifics of their upbringing. But these theories aren't entirely baseless, and are usually rooted in studies on animal behavior, especially that of great apes and other primates. I suspect the vlogger didn't mention a lot of stats because lots of text AND numbers will scare away lots of lay viewers

a decent, very basic run down of the mating behavior of sexually reproducing animals. I disagree a little about the reasons why the males of some species don't use the "rape" alternative mating strategy. Ineptitude may be the reason in some cases, but in many, especially the penguins that the author (videographer? vlogger?) depicted with that paragraph, it's because that strategy simply won't work. Emperor penguins raise their young in a VERY tough environment, and you simply need both parents to commit to caring for the offspring if it is to have a chance to survive, and they need to work together. "Raping" a lot of females won't do you much good if none of the babies survive without your help, and even if you "rape" just one female, if the two of you don't get along, the offspring don't stand a good chance. Forming a single, cooperative bond is the best bet. Many human behavioral ecologists think this is also the reason for human monogamy - human children take a lot of investment to raise successfully, so the male needs to commit to and work with his mate and invest a lot in his child.

Am I just out of it, or is this not really anything that earth-shattering? It's called historical constraint, and it's something that I learned about in my first class on evolution. There are traits or suites of traits that evolve in such a way that they can't really be "undone," so any further adaptations or changes have to be done within the constraints of those traits. Animals evolved with one head, so at this point in the evolutionary tree it's pretty much assumed they can't evolve to have two. I think calling it "mutations imposing a direction to evolution" is just calling a rose by another name, as it were. I also think it's not necessary to decide which one is more important, mutation or selection. Doesn't evolution require both? Variation and differential selection of that variation?

Thanks, INow. But I would go even farther and say that even a pit bull that has previously been raised badly can potentially be trained away from that behavior. I know I'll probably get snarked at for citing a tv show here, but if you ever get a chance to watch the Dog Whisperer on the national geographic channel, you'll see what I mean. Cesar Milan has a reputation for being able to rehabilitate even highly aggressive dogs. Like I keep saying, there's that 10000 years of selective breeding of dogs for obedience that is in every breed, no matter how aggressive, which enables dogs to be controlled and trained by humans unlike few other animals.

I don't think the problem is necessarily with the pit bulls themselves. They are bred for aggression but they, like all other dogs, are also bred to listen to people. In the hands of the right owner, any pit bull can be as safe as a kitten. But the real problem is that not every owner has the desire or knowledge to safely control their dog. So if a country or state wants to ban a certain kind of dog because they can't trust that their owners will be responsible, then that's their decision to make.