Ahmad

That's as fas as I know, yes. Note that this only applies to what is called dynamic exercise, in which the muscles keep contracting forcefully and periodically. It doesn't apply to static exercise, like weight lifting. So it depends on what you are talking about.

Bioweapons research in the field of molecular biology are more toward targetting specific people. Imagine a virus that can only affect white men, because of the similarity in their genome. The US army as an example contains people from different gene pools, but you have the chineese army for example. Chineese have an isolated gene pool and will probably have similar responses to specific types of diseases.

I'm not sure how related is that to the heart rate, but the warm-down period is very important in this case for the pressure change. In this case, an individual is doing a dynamic exercise in which his muscles are contracting. These muscles have blood vessels going through them, and when they contract, they help in moving the blood towards the heart. They also cause a rise in mean arterial perssure. In this context, these muscles are called "booster pumps". When these muscles are working very hard, their componenet in the mean arterial pressure will be very high. If they stop working suddenly, their large contribution to the current mean arterial pressure will go away, and there will be a large pressure drop because of that. This is why you should stop your muscle action gradually, to allow the regulatory mechanisms to follow up until you reach resting state.

Just to add to that, the heart of a trained athlete does have a lower heart rate, but that doesn't mean that it is not doing the same amount of work. It will be beating less frequently, but each beat will be stronger. Each beat will use a higher amount of energy than that used in the beat of an untrained person. This is because it needs to pump more amount of blood per beat. The amount of work a person has to do is better correlated with the amount of blood he is pumping per unite time, or the cardiac output, which is basicly the same for trained and untrained individuals in the resting state.

This is exactly what I used to think long ago, but I'm not sure anymore. There are still many things about color that we still all agree upon .. One such a thing is the colors most people percieve as matching. There is also how most of us agree that two colors are "close" to each other. Don't you agree that green is more similar to blue that red? This could also be attributed to the physical properties of these colors, but if I was to immagine in my head the colors green and blue, I would still think they are close to each other.

The other way around.

Some people where argueing that homosexuality is a reason for infertility, and based on that, they said that it cannot have any genetic causes, because infertility is against natural selection. So my point is this: even if it reduced fertility and fertility rate for homosexuals was zero (the lowest), that doesn't mean that there can't be any genetic cause (or influence) fot it. To better show my point, I refered to an arbitrary article about several diseases that can cause complete infertility, yet they are influenced by genetics. I'm not saying weather it is genetic or not, I'm just argueing a certain point that was made during the discussion. I think that Skye made my point very clear. Thank you Skye Anyway, I think that homosexuality does decrease the rate of fertility. The means by which homosexuals can reproduce are not possible in most of the world population because of social and technical problems. I'm not sure about the terminology: genetic causes, genetic influence? In all my discussion before this post, when I mentioned any of these terms I mean that it can be inherited. i.e.: can run in families. i.e.: you be more likely to have it because your father and your mother are who they are.

For those who still think that homosexuality cannot be genetic because it is against natural selection, please read this paper with a lot of information about genetic causes of infertility: http://urology.ucsf.edu/patientGuides/pdf/maleInf/Genetic_Causes_Infertili.pdf

This occurs if the testosteron level was high during a certain period of development. I can't imagine anything like this happening by testosterone administered after birth. The same goes for genital organs.

Sorry DocBill, I didn't mean to be rude. I was really serious about what I'm writing, but your sarcasm shocked me.

Also, as the mechanism of loosing useless phenotypes is mutations, which is the same mechanism for gaining new phenotypes. So phenotypes are added and eliminated from the species all the time by the same mechanism. What is it in this mechanism that makes removing useless mutations more favorable than adding new ones?

You are obviosly missing my point. Maybe you didn't read my comments from the beginning. In case you did read them but didn't understand them, let me explain them more to you. Defining weither ones life is convenient or not is something very relative and not part of my speciality. The point I was making is that some features that we have make our lives more convenient that if we didn't have them. Again my example, how did we acquire voluntary control over macturition and defecation? Why isn't it involuntary like in other animals? Why did we get that feature and keep it? Let me explain this more to you. If the only driving force for life and evolution was natural interactions and trial and error with different combinations of genes, then, statistically, we are supposed to see a HUGE number of phenotypes that aren't neccessary for sustaining life in hour bodies, but we must supposingly acquire them through the process of trial and error that we've gone through. So your reply is that these phenotypes that we would have aquired will get lost because there is no pressure keeping them. As I barely find any un-necessary phenotypes in my body, this mechanism of eliminating such genes must be very efficient. Now my comment on this is: what is keeping these phenotypes that are not necessary to sustain life or preserve the species, while they are useful to us.

Still, that doesn't say why do we get to keep many things that make our lives more convenient, yet they are not necessary for our existance. While we don't keep many other things that we might as well have had.

Actually, nothing is selected for. Things are always selected out! Anyway, many things stay in the genome because they are recessive. They are carried by some people, and when they reproduce they give an individual with the phenotype. Just like many of the purely genetic diseases that cause mental retardation or other types of disorders that prevent them from being able to reproduce.

This is so funny. Funny, but not convinceable.