Paralith

I don't see why you find it so unlikely that a significant amount of lethal shark attacks could go unreported. We're talking about the ocean, here. Even in coastal areas, we're talking about vast areas with a very thin concentration of human life. As others have said, many people simply go missing without any actual knowledge about how they died, or what they may have experienced in the hours/moments before their death (a single weakened human floating in the ocean about to die from exposure is probably easy pickings compared to a pair of healthy swimmers). We're not saying for sure that there ARE lots of attacks that go unreported, but you can't deny the possibility. It's difficult to answer the question of why there are less than expected shark attacks if you're not even sure of the actual frequency of shark attacks in the first place. Even so, I'm not even sure it's right to base your expected number of shark attacks on number of attacks by land predators. Once again, pure density is probably the largest culprit for any discrepancy. We humans are crawling all over the dry land, and are relatively nonexistant in the oceans when it comes to cubic space. We are simply not a typical factor in a shark's life, so their reactions to humans are probably highly variable depending on the specific circumstances of the encounter.

Being a biologist myself, I'll put my bias out in the open and easily admit that I dislike the idea that chemistry and physics require more "smarts" than biology. That being established, let's move on: I can't deny that biology, especially learning introductory biological theory, is a lot of memorization. However, a lot of advanced biological theory and especially practical biological research ends up involving a lot of chemistry and/or physics and/or math. After all, life at its basis is physics and chemistry, but in an organism there are layers upon layers of complexity of chemical interactions that result in the higher level functioning of that organism. We're talking about seemingly endless amounts of different phenomena, and trying to understand the governing mechanisms behind them, how they all interact with each other, their history, etc (depending of course on the specific sub-field you're talking about - biology is a ridiculously broad term and encompasses many specialties; though I'm sure chemists and physicists will say the same thing about chemistry and physics ) So yes, biology does involve memorizing a lot of things - but then you take this knowledge about all these many, many different things, and try to understand and puzzle out their interrelationships. I currently work in a biomedical research lab, and the amount of work we do to identify, characterize, and verify a single relationship - say, the hypothesized statement that the gene Pitx1 is upregulated in and contributes to the disease FSHD - is really rather astounding. That relationship itself is interwoven into many others - how exactly does Pitx1 function normally, how does that function change as a result of upregulation, what about the disease triggers this upregulation, what other genes and environmental effects act on Pitx1, what genes does Pitx1 act on, what are the gross morphological effects of excess Pitx1 protein and do these effects match what we see in the disease, etc etc. By exploring all these things and comparing the knowledge we gather to previously gathered knowledge, hopefully we will slowly piece together what's really going on. I don't know if the intellectual demands of physics and chemistry research are quantitatively more or less than this, but it's definitely nothing to scoff at.

I have several thoughts on this. First of all, if we follow your terminology that lions will kill a person "without hesitation if given a chance," then I think my own personal experience has disproved that. I've been on safaris myself, and gotten very close to several lions in a very open truck that was not particularly high off the ground. If humans really were a prime menu option for lions, then I think my truck and many others like it or even more open than it would be highly unsafe; a determined lion would have no trouble getting to a person inside one. Secondly, simply by being on the ground, a human enters a much more prey-like position relative to a lion. And I don't know the details of the story you related, but I'd imagine that once the woman saw a lion stand up and move towards her, her first instinct was probably to run back to the bus. Thirdly, there are several other reasons why a lion might kill another animal that are not related to their desire to eat it. A threat to females and cubs can easily arouse the aggression of a pride male. Lions are also known to kill cheetahs and hyenas, adults and juveniles alike, and not eat them. They kill them because these species are the lions' primary competitors. In fact, lions in a park will learn that tourist trucks relentlessly mob the few, poor cheetahs in the park whenever they are sighted (the trucks literally form a circle around the cheetahs, following them wherever they move, and it only gets worse when other drivers see the commotion, and zoom in ASAP to get their load of tourists a photo opportunity - again, this is from personal experience). The lions will follow this commotion to the cheetahs, and kill them. I think behaviors of this kind are less common in sharks, and I think in general they are less likely to view a human as a threat to them that needs to be attacked rather than escaped from. Fourthly, lions in a park are exposed to hundreds of tourists on a nearly daily basis. Many sharks, especially the larger ocean-going ones, spend a vast majority of their time out in open ocean with nary an mammal to be seen, let alone people. In short, land predators like lions have much more opportunity to develop abnormal behaviors in relation to humans than sharks do. And to connect back to my third thought, they also have much more opportunity to learn to recognize humans as threats of some kind. A lion has a limited territory where he hunts and where his females live; a shark has giant swathes of ocean it can retreat to should should it encounter an unpleasant human. Unless a solo person presents a much less threatening situation than a mob of thrashing humans, making it more likely that the shark may approach and investigate the possibility of an easy meal.

Hi Lance, sorry I'm late to this very interesting discussion. I mostly agree with your original theory, that most shark attacks are probably investigatory, or that some aspect of the human and/or its behavior at the time elicits a predatory reaction. Along these lines, they say that the worst thing you can do when faced with a big cat is to turn and run from it - running is prey behavior, and even though they may not have been particularly interested in you to begin with, you can elicit the predator's instincts by acting like the food they eat. (Anyone with a pet cat knows how much more interested they become in a given toy once it starts moving.) I suspect that this happens a lot with shark attacks on humans as well. I think you're underestimating the effect of "fighting off" a shark, though. You don't have to represent a significant threat to the shark to make it go away - you just have to cost more energy in the struggle than the shark will get from eating you. I remember a study done on lizard-eating snakes - if the lizard struggled for a certain amount of time, the snake would let it go - the cost of the meal was going beyond what it was worth. These lizards posed no actual threat to the snakes other than inefficiency. Even if a shark has gone beyond the initial reaction/investigation and does decide it wants to eat this human it has in its mouth, if it seems like the human will be too hard to subdue, the shark may then decide it's not worth the effort. This may help to explain the USS Indianopolis incident somewhat. Many of the sailors in the water were already injured, and all were tired and weak from the ordeal of the ship's sinking, and only became more so as the days went on. I agree that the role the sharks played was probably exaggerated to some degree, but I wouldn't be surprised if some sharks did take advantage of their weakened state.

Hmm. I think women in general tend to prefer more personal interactions. There is also a general computer sufficiency bias that leans in the males' direction, for various sociocultural reasons, that probably discourages a decent amount of women from in-depth internet forays. These differences will diminish as time goes on, though, and internet interactions become an increasingly important part of people's lives in general. This forum in particular is also fairly representative of women in science in general. There are simply more men in the field. For now.

You're also going to need pipettes. The ones we use in my lab are $300 a pop, and you'll need at least a few sizes (10 ul, 200 ul, and 100 ul, I would say). The reagents themselves will get expensive, and you will have to continually replace any consumables as you use them. Tips for the pipettes will be about $50 per case (has ten boxes), more if you want filtered tips which are a good idea if you're working with bacteria, to prevent contamination. A 100 g bottle of pure agarose to make electrophoresis gels with is over $100. PCR reagents, media, petri dishes, tubes of various sizes, TBE, antibiotics, etc etc. It tends to add up. Just keep that in mind. Not to mention the fact that PCR reagents (at least the polymerase enzyme) need to be kept at -20 degrees C, and if you buy competent bacterial cells (for transformation aka plasmid uptake) they need to be stored at -80 degrees C until they are used. So you'll need some heavy duty freezers. And probably a bunsen burner to help keep the area sterile when you're working with your bacteria plates.

Firstly, the parents should be able to pass down the mutation, because it is artificially created in them when they were embryos, so the mutation is in all their cells, including their gametes. Secondly, yes sometimes the mutation can be lost, especially if you're dealing with in inserted plasmid (I'm not familiar with the exact mechanics of making knock-outs). But there really isn't much you can do to prevent that. You must genotype all your pups, whether it be via PCR or RTPCR or Southern blot, before you use them in your experiments to ensure that they still have the inserted mutation.

Hopefully, but like I said, it depends on what kind of experiment you're doing. But that's what we do in our lab - we just test the mice when they're at the correct age. It might mean spreading out the tests into 4 or 5 repeats, but that's how it is.

Is this a homework question, tman?

Well, you'd probably start with making the knock out in 2 or 4 mice, half male half female, and breed the rest of them from these initial pairs. It would be far too difficult and expensive to artificially knock out all 50. Though breeding babies makes things a little more tricky if you need them all to be the same age, or have a specific gender ratio. How important that is depends of course on the nature of the experiment you're trying to conduct.

I don't think it will be successful without some genetic tinkering. Neither parent will have a Y chromosome, and the Y chromosome contains some genes that are required for the development of fully functioning sperm.

The individuals of most species die long before they get physically too old to breed - and not typically by suicide, either. Predation, starvation, accident, disease, killed by a rival, etc.

Jerry, from the get go you appear to have a misunderstanding about some basic scientific concepts - mainly, the difference between proof and support. Logically, it is impossible to 100% prove anything. There is disproof, and there is support. Scientific hypotheses do not reach the level of theory until they have been repeatedly and substantially supported and have failed to be disproved. Evolution by natural selection is such a theory and is one of the most well supported theories in science. Along those same lines, a computer simulation is not proof. It is support - it demonstrates that, based on parameters observed in nature, it is possible for such a system to occur. You are right to question how accurate those parameters are, since that is ultimately what determines how accurately a computer model can represent reality. I'm not very familiar with the subject matter in the video so I can't say myself - probably Lucaspa or someone else better versed in these things can weigh in on that subject. However, I'd like to point out that the single base pair mutation that causes sickle cell anemia is, when heterozygous, advantageous. Individuals heterozygous for this single base pair mutation are more resistant to malaria, and this advantage has been so great that the mutation has persisted in the population despite the obvious disadvantage suffered by individuals homozygous for the mutation. So there is your example of an advantageous single base pair mutation. You offered it yourself. To address your three questions as best I can: Q1: if we're only talking in terms of what may support or disprove evolution, then abiogenesis has no relevance to the topic. Evolutionary theory only addresses the changing generations of life, not what came before it. A problem with abiogenesis does not present a problem with evolutionary theory. It's definitely a difficult topic, and researchers have yet to come to a solid consensus. However, I wouldn't necessarily say they are working on "negative proof," as you call it. We don't yet understand it, so - we don't yet understand it. And we're working on finding ways to understand it. That's all. There's no implicit suggestion that it MUST have been one way or another. We just have yet to figure it out. Q2:Yes, you did. Q3: Irreducibly complex arguments never stand up. Time and time again, they have been disproved. I do not know much about this specific mechanism myself, and unfortunately do not have time right now to research it, but I will later and post again.

generally, if you're having trouble researching a specific question, start by doing some general research about your subject. All that information that martin found can be located by a simple google search for porphyria. You may have been trying to be too specific with your search terms.

Oh yes - there are very strict laws in place that protect the privacy of personal medical information - the HIPPA laws. At my workplace in the research department of a hospital, we all have to go through training to understand these laws, especially since we may be using human medical data in our research - and since I work in the genetics department, this most certainly includes DNA sequences. If we do use this data, extra precautions must be taken to protect the identities of the participants. Any research involving humans in any way is reviewed by an IRB committee and put under strict scrutiny before it is approved.

Not necessarily - not if you can continue to aid your offspring even after you yourself can have no more. You can help them have more.

....what?

What dangers are you thinking about, exactly? The act of DNA testing itself is not physically dangerous to you - they do a cheek swab or draw blood, then work with the sample in a lab. Are you worried that some people might use your DNA information for nefarious purposes?

I don't think anything in the cell would be a good analogy to the brain. The brain actually takes in, processes, and stores information about the outside world. There is no particular structure in the cell that performs this type of task.

Sam, the only time in this thread that you seriously defended your position in life, you did so largely on your own account. When I stated that you were not a practicing research scientist in this field, it was only to say that NONE of us are right now, that we ALL are expected, as reasonable people interested in science, to conduct our discussions with integrity and be able to back up our claims with supporting references. I don't think I necessarily agree with Sayonara about debating with scientists - because most of the members here are not practicing scientists. But this is a place where we uphold sound scientific practice, regardless of what you do or do not do in real life. If you feel the profound need to defend your real life practices and status in this forum, I suspect it is largely due to a perceived threat, and not an actual one. I personally don't care if you've never done biological research. I'll still debate you either way. I just expect you and myself and every other person here to debate with integrity. That's all.

Again, you keep putting words in my mouth that I did not say. It's quite irritating to debate someone who keeps responding to points I never made. To be clear: I never said you can prove anything. I said, provide a source that SUPPORTS - not proves, SUPPORTS - the statements made. And I don't know what point exactly you're trying make with all your ranting about "never being sure of the truth;" what I meant is this: Say for example, you describe a certain species of red bluejays. I have never heard or seen of such a thing, nor do I think that birds called bluejays would be red. I ask for a source; a published paper and/or a guide book on exotic birds etc is pointed out, and I find out that yes, there are recorded observations and studies of red bluejays. But, if all you've got is cross-my-heart-swear-to-die I've seen one myself, well, I'll admit to the possibility that you did, but also leave open the possibility that you were mistaken. Note that I am not declaring ultimate absolute truths here. Sayonara answered this one well enough. Ideas are the starting point, and I am not going to condemn a new idea simply because it is new. But I will reserve judgment until the idea is tested. Haha, this is quite amusing. So, for the idea that chronic pain causes emotional reactions that are indirectly related to the pain itself, acceptable support of this idea, in your mind, is your telling me that you have had this mental experience. And yet, in your earlier posts, you condemned using first hand accounts of one's thoughts as support for theories about the nature of mental activities. According to your own words, dreams are the only window to the true nature of thought, and we humans are incapable for one reason or another of actually communicating to each other through language with absolute truth the nature of our dreams and therefore of our thoughts. Yes, Sam, you could have told him that - but like you, he didn't put his complete trust in first hand anecdotal accounts. They probably played a large role in seeding the IDEA in his head, but then he set about finding objective evidence in support of this idea. At one point in history, many people would have looked at the statement "light objects fall more slowly than heavy objects" and said, "Ha! I could have told you that!" but objective testing of this idea found out that it was false. Human discussions and ideas are invaluable to science, but it's the testing of the hypotheses that come out of these processes that is the essence of science.

No, not "any and all". Please don't put words in my mouth. But if you make a statement that goes contrary to what I or other forum members know/understand, then it is only reasonable that you provide a source that supports your statement. The same is expected of all of us. When it comes to a highly complex biological structure like the brain, I would expect that it will take a good deal longer than "years n' years n' years" to completely unravel it. And I'm not sure what counts as "much of anything" to you, but from what I can tell they're learning new things all the time. Did you yourself not just link to a paper that made a new discovery about the workings of the brain? Check out some journals on neuroscience and neurobiology - chock full of papers and coming out with more all the time. They may not have yet answered all the questions we have about animal and human consciousness, but I wouldn't discount all the existing knowledge as being not "much of anything." It's certainly more than we knew even fifty years ago. Haha, yikes, don't get so riled up. Did I ever say that all people are 100% truthful to each other 100% of the time? I would hope not, as that's a silly statement to make indeed. What I was trying to point out is that, relative to studying the thoughts of animals, we can get a better idea of the thoughts of people because we can communicate our thoughts to each other. These communications may not be 100% completely accurate in every detail, but a reasonable amount of honesty can lead to a reasonable assessment of some aspects human thought. A type of assessment that can't be made at all with animals - except perhaps with a few particularly bright non-human primate individuals that are taught sign language. The comparison was my point, Sam. It goes without saying that simply talking to another human is not enough, all by itself, to completely understand all aspects of thought. Hell, even those of us willing to talk about some of our dreams probably can't remember most of their content anyway. Human language is not the ONLY way we can study thought, just one of the ways in which we can gain some additional data, taken with a grain of salt.

All I'm trying to say, Sam, is that you are not a currently researching scientist in this particular field. I'm not trying to insult you or what you may have done in other fields at other times. As neither you nor I nor Lucaspa nor anyone else in this thread (so far as I know) are currently researching scientists in this particular field we all have to look to the work of people who are. I not sure what you mean by suggesting that I'm biased against the very thing I'm trying to resolve; nor am I trying to say that human thoughts are that much more well understood than animals' thoughts, when it comes down to the nitty gritty of brain function and what exactly is going on in there. If my statements seemed to suggest otherwise, that was my mistake and I apologize. To rephrase: until we have increased knowledge and better understanding of how thought processes work and how to compare them between us and other animals, we can't be 100% sure either way. We do, however, have a greater (though still incomplete) understanding of our own thoughts than of animal thoughts, because we humans have language with which we can explain our more conscious thoughts to each other. Even with animals, though, certain behavioral tests can be done to test various theories about their mental processes. I'm more familiar with these, as I have read about several of them recently. And beyond this, advances in neurobiology are slowly unwinding the very basis of thought.

The offspring of a female lion and a male tiger are called tigons, and the offspring of a male lion and a female tiger are called ligers, and they are the largest cats in the world (siberian tigers are the largest pure cats in the world). Only female tigons and ligers are fertile; males are sterile. The key thing to think about when it comes to defining separate species is a barrier to gene flow. The most obvious barrier is of course physical separation, but behavioral and anatomical barriers can also work just as well. If the males and females of two different species don't give each other the right behavioral mating cues, then they might not ever mate, even if their ranges overlap and they were physically capable of having fertile, hybrid offspring. It's all a moot point if they never mate in the first place. Lion and tiger hybrids have been known to occur in the wild, but very rarely, probably because even when lion and tiger ranges did overlap in the past, the behavioral differences prevented most potential hybrid matings. And what small amount of gene flow that might have come from these very few female hybrids is not anywhere near enough to begin a true hybridization of the two species.

To Sam: Perhaps I should have clarified. Whether or not you were ever a practicing research scientist was not my point. In the current subject under discussion, you are not a research scientist. Work on fMRI's is all well and good but unless that work can offer some support of statements you made about the dreams of animals and whether or not they are abstract and conscious the way they are in humans, that work is irrelevant to the subject at hand. And because you are not actively out there gathering support for this subject, any arguments you make in this subject have to be based on existing data. And as Sayonara nicely pointed out for me, even Stephen Hawking does this, as well as a lot of actual mathematic proofs. For your example with the horse, as well as many other anecdotal examples of animal behavior that seems similar to human behavior, it is possible that this does indeed represent conscious, abstract thought. But it is also very possible that it does not. The alternate explanation could be given that, the horse had learned an association with humans and its care - with humans and feeding (in the winter), humans and grooming, etc. She may not like every human that cares for her, but care for her they do. So when injured and in need of care, she simply knew that if she waited for a human to come, care for her injuries would shortly follow. As you were the first human to find her, she waited for you to care for her, and you did. Association fulfilled, she left. This is logical of course, but not very abstract. Whether or not she thought to herself, "Dammit this hurts, I hate that human but I know he'll see me in pain with these quills in my nose and then he'll take them out, so I'll let him near me. After that, though, I'm outta here," is doubtful. This requires a level of self reflection that most animals probably can't accomplish; but at the very least, until we have better methods of understanding the mental thought processes of animals and comparing them our own, we can't be 100% ure either way.