Paralith

In general I think it's safe to assume that keeping our crops and food animals clean, healthy, and parasite free will result in more production. And doing so is an ongoing challenge in the agricultural industry. Like I said, I don't know a whole lot about all the possible effects of radiation; I wouldn't be too surprised if small amounts of controlled radiation in certain situations can have unexpected benefits. But if your goal is to consistently replace old cells with new ones, even if it's not necessary, I don't think using radiation is the way to go. Your body does have its own mechanisms to detect and eradicate unhealthy cells, after all - otherwise we'd get cancer a lot easier. And again, increasing the cell turnover rate will not necessarily make you healthier, but it will increase your risks of getting cancer.

First of all, you have to stop thinking in terms of "improving" the ecosystem. I mean, think about it: what exactly makes one ecosystem better than another? What does it mean to have a positive effect on an ecosystem? You need to think about defining these ideas. For example, it is possible to have one ecosystem that is more stable than another, that isn't rapidly changing into a very different system, such as a changing environment, or one species rapidly taking over where it didn't before, etc. But is a stable ecosystem "better?" For the organisms living in it, maybe. But not for those organisms that would do better in a different type of environment. Some ecosystems are more productive than others; a rainforest generates much more biomass every year than a desert does. But that's mostly because of the physical environment - all the sunlight in the world won't do a plant much good if it has to keep its stomata closed all the time to prevent the loss of precious water - and therefore unable to take in more C02. "Better" is a much too subjective term to apply to something as complex an ecosystem. Find out exactly what it is you're really trying to achieve - more biomass production, more stability, more diversity? But don't say, I want a "better" ecosystem. Some parasitic organisms do keep their target animals in check. In the rainforest, there is a whole slew of species of fungi, each specifically targeting a certain insect. And to reproduce, these fungi inevitably end up killing their host. Some researchers believe that without this pressure from the fungi, insects may very well take over rainforests. But if they did, that wouldn't necessarily make the rainforest less stable - just different (after a period of change, of course) in its species complement than it is today. I'm not sure what you mean by "automatically controlled by concurrency, food access;" there are many other ways different animals effect each others' population size. Lynx popultions and the population of their primary prey, rabbits, will go through opposing osciallations over time. That is, as rabbits increase in number one year, Lynx increase in number the next year as they can feed more. But more lynx eat more rabbit, and the rabbit number goes down the next year. Less rabbit means less lynx food, so the lynx number goes down the year after. Less lynx means less predation on rabbits, so again the rabbit number rises. Again with the subjective terms - "improve," "weak," "effectiveness." Whether or not an organism is considered strong or weak will depend on its environment. A polar bear may kick all butt in the arctic, but plop it in the middle of an the African savannah and it would probably quickly overheat and die. An animal that lives a lot in burrows and has evolved defense mechanisms against most parasites will not suffer from parasitic infection as much animals that rarely have to deal with parasites - and thus have fewer defenses. And how do you "improve" selection? Even in humans, where many people think natural selection no longer holds much sway over our evolution, perhaps sexual selection is now more prevalent, or even cultural selection. Is one of these types of selection better than another? Evolution doesn't "throw" out anything; a species will die when it is no longer able to survive in its current environment, and cannot adapt. And what makes an ecosystem more effective? Do you mean more productive? Do you mean more stable? I think you migh misunderstand how radiation effects cells. The most significant effect of radiation is its mutagenic one - its ability to mutate DNA. While some cells will probably die, others will live, some of which are mutated, and several of which will probably become cancerous. Also, a higher frequencey of cell replacement requires a higher level of cell division, as that's how you make new cells. Every time a cell divides, it has to replicate its DNA, and every time DNA replicates, there is a small chance an error will occurr, and a small chance that error will go unnoticed by proofreading mechanisms, and a small chance that the resulting mutation will result in a cancerous cell. So the more cell growth and division there is, the higher the odds are that cancer will develop. Though I suppose if your goal is to stress an animal, giving it cancer will do just that. All organisms are susceptible to many different kinds of stress, and are usually subjected to at least some of them throughout their lifetime. I don't see a need to go out of our way to find new sources of stress for organisms. If an organism's environment changes in such a way that it is no longer adapted for it, it will experience stress, and the species will either adapt to the new environment in some way, or it will die. Selection will work within its context. We don't need to "increase" or "improve" it, unless you're trying to select for something specific. And as I've already said several times, this is what you need to do: figure out exactly what your goal is. If it's efficiency of energy conversion, I've already addressed that in my first post. If it's something else, you need to define it.

In a word, yes. A complex interaction between genetic and environmental influences, about which there is still very much left to learn.

If you want to convert solar energy into energy stored in organic molecules more efficiently, then it isn't the whole ecosystem that you need to look at - it's the molecular mechanics that actually partipate in energy conversion, and these have a limited efficiency. Only a certain percentage of the total light energy that plants absorb is actually put into carbohydrates, and only a certain percentage of the energy in plant carbohydrates ingested by herbivores can actually be extracted for their own uses, etc. Much of the energy in these exchanges is lost to heat, etc. Without getting down to these base mechanics, I don't think a significant change can be made in the efficiency of organismic energy conversion. Besides the fact that creating a perfect ecosystem isn't really the way to achieve your goal, your ideas about creating a "perfect" ecosystem in the first place are kind of flawed, such as creating organisms without "opposite interests." If you have a herbivore that feeds on a plant, there are opposite interests. If you have two species of plant that both want to take root in the same patch of soil, you have opposite interests. If you have two individual neighboring plants that are both trying to suck up the water in the surrounding soil, then you have opposite interests. There is really no way to remove competition 100% from an ecosystem unless you have nothing but a single organism - and that's not really an ecosystem - or unlimited space and resources - which just isn't practical. You also mention removing organisms that don't contribute anything "positive" to the ecosystem. Ignoring that "positive" is a highly subjective term and maybe not even applicable, even something like a virulent virus or locusts can have positive effects on certain organisms. A virus that effects predators helps take the pressure off of the prey. Locusts that tear down large vegetation clear up space for new smaller plants to take root after the locusts have passed on. Ecosystems are complex, intricate entities, and I don't think there is such a thing as a perfect one.

NIH puts a lot of effort into researching a lot of diseases, not just because they are on the rise, but because they can be devastating to the people who have them. And I'd imagine that if you look at many other complex genetic disorders, that they also appear to be "on the rise" due to increased awareness.

In the animal world, "cheating," also called extra-pair copulations, or EPCs, can be common, even in species traditionally considered monogamous, especially birds. A female can gain multiple benefits from a mate - genetic quality for her children, and direct aid in raising them, receiving food, etc. But, not every female can have the male of best genetic quality for her mate. So, she will pair with a male that can help her raise her offspring, but then sneak off to mate with the male of high genetic quality. And that male won't turn down a chance to have offspring that he doesn't even have to take care of. It's very possible that a similar situation occurred when humans were evolving. But notice lucaspa said in this society, as in modern humans today. Things are different now then they used to be, I think that much has been easily established in this thread. But, as has also been stated in this thread, many of the mechanisms that worked thousands of years ago have yet to change, to catch up to this change in environment. Today, if the people participating in EPC are smart, they use birth control, and no offspring result. So, in reproductive terms, better to stick with one mate with whom you agree to have children. Obviously, there are complexities and situations in which things are a little different, but generally, this is the case (I think) lucaspa is talking about.

Hello. I've actually been posting for a while now, but I sorta missed the fact that there's an "introduce yourself" thread. Oops! ^^; I am addicted to cheese puffs and I enjoy small cats that dress up like food. (http://en.wikipedia.org/wiki/Nyan_Nyan_Nyanko - based on my informal research, if you are female you will find this very cute, if you are male you will find it utterly ridiculous. Let's see if my results are supported!) To illustrate my dorkiness, I chose my avatar because it is of a species of butterfly whose genus name begins with the same letter as my first name, and whose species name begins with the same letter as my last name. And yes, I did have too much time on my hands.

but if they didn't make sure that rat poison kills rats, and they sold rat poison that doesn't really work, then you would get more rat infestations in buildings with people, and more small children may suffer painful bites and possibly get terrible diseases. Animal testing can benefit human life in many more ways than just vaccines, though most people agree that testing cosmetics on animals is pushing the limit. However, I think it's rather silly to question whether or not rats feel pain. They way they struggle and squeak when you stick them with a needle should tell you that at the very least they'd much rather be doing something else. If we're going to do animal testing, I think it's important to accept that yes, it can be painful, and yes, they probably don't enjoy it. Then you take what you're doing seriously, and you don't start testing cosmetics on rats because who knows if they feel it anyway.

http://www.google.com/search?q=microorganisms&start=0&ie=utf-8&oe=utf-8&client=firefox-a&rls=org.mozilla:en-US:official as a friend of mine likes to say, go read the internet.

The important thing you have to keep in mind about studies like this is that they don't say that decisions are made "automatically." They say that when confronted with certain problems or situations, your brain, in essence, encourages you towards certain conclusions. Rewards you if you make certain decisions by making you feel good. But just because we are offered encouragement or awards doesn't mean that we're bound to follow them. We can still choose to make a different decision, even though it might make us feel bad. (And when I say "we," I mean humans. I don't know if other animals have this same capacity - I would guess that less intelligent animals simply follow the rewards their brains give them.) In general, the fact that we are encouraged to be altruistic in some ways does not suprise me. In a species where social standing can be key to reproductive success, it pays to behave in ways that make you look good to others. And if it feels good to be nice to others, then that behavior is more likely to happen.

Whoops. My apologies. I did miss that. That's not necessarily true - it depends on the environmental context. If the environment in which you live is relatively stable, then variety is not immediately necessary to the propagation of your alleles. Especially if it is easier to have more children with one mate then it is to maintain two mates. Unless having varied offspring increases the number of your alleles that ultimately remain in the population more so than having offspring from only one mate, then this behavior won't be worth the effort and will not be selected for. For the majority of time in the majority of places, a relatively stable environment is the case. And besides, even with just one mate, there will still be some variation among your offspring due to the nature of sexual reproduction. This is assuming, of course, that the ONLY benefit one can gain from multiple mates is an increase in the genetic variety of your offspring. There are plenty of other possible benefits one can gain by having multiple mates, but usually variety is not the driving force behind them.

Sterilization of agar and plates is usually done in an autoclave machine, which reaches much higher temperatures than microwaves, and are designed for sterilization. If you're working at a research facility it's standard to have one.

I'm not saying that people can be unselfish because we're all related somehow. I'm saying that one hypothesis for why humans can be so altruistic with each other is that during our evolution, we lived in family groups. In more recent times, this has changed, but there is usually a lag time between the change in the structure in the environment and the evolution of populations to have genes optimized for the new environment. Saving a five year old over an 80 year old would have been evolutionarily favored in the family-group environment, and so we have the genes to encourage us to do so. Today it might not be evolutionarily favored, but the genes are still there, as they haven't had time to adapt or otherwise change. (I'm not forgetting that the human consciouness can overcome their genetic moral suggestions if they want - just discussing the genetic aspect alone at this moment.)

I'm assuming you're talking about movement of sugars in a plant, which move according to the "source-sink" model. They go from a source of sugars, where they are constructed (such as in a leaf, from photosynthesis) or stored (such as a tuber, etc), to a sink, where they are needed for growth or energy. Mineral nutrients and the like are distributed through the plant in the xylem water, which moves from roots upwards to shoots. Sugar movement in the phloem is not unidirectional, and depends on where the source and sink are, which can change. If that's what you're asking, your question is in the wrong place.

I don't think prisoner's dilemma** really applies here; in the scenario from the OP, there really isn't much the people about to get run over could do to significantly betray the person helping them; ok, so they could not reciprocate in the future, but it's no gaurantee the situations will ever be reversed. Also in a single-occurence prisoner's dilemma, each party is unaware of the other's actions, and that's also clearly not the case in the OP. Also, as far as not caring that any offspring to come out of the five year old wouldn't be related to you, this might not have been the case in the environment in which our morals may have been evolutionary shaped. Evidence suggests that early humans often lived and/or traveled in large family groups, so most of the time, if you're going to risk your neck to save someone, they will probably be related to you. This is also part of a hypothesis about adoptions - why go to all the expense and effort to raise a child that's not yours? In this model of early human life, a stranded child in your group is probably related to you in some way, so our genes evolved to encourage the adoption instinct. **for people who might be unfamiliar with prisoner's dilemma: two criminals who work together are caught by the police, and put in separate interrogation rooms. If they both stay silent, the police only have enough evidence to put them both in prison for 5 years. If one gives up his partner, he will get 1 year of prison and his partner will get 10. If they both give each other up, they both get 15 years. In most studies, when put in this situation once, both parties often end up betraying each other. But other studies found that if this interaction happens repeatedly, that the partners will learn to work together. A real life example of this is trench warfare in WWI - groups of enemy soldiers stationed in opposite trenches for long periods of time began to cooperate with each other - only bombing each other at certain times every day and the same place every time, etc, so both groups could still act like they were fighting, but nobody would die. Generals had to regularly move units around to prevent this from happening.

I suggest visiting this forum: http://www.protocol-online.org/forums/index.php It's a forum that mainly discusses scientific procedure and protocol. You might even be able to find some sticky threads that have already discussed your question.

You really need to stop thinking that organisms can somehow "decide" or "choose" how they evolve. They don't. Random mutations that are advantageous in one way or another build up over time. Let's take sight as an example. The origins of sight lie in sensitivity to light. Unicellular photosynthetic organisms often have eyepots, light sensitive cells that tell the organism to move toward the source so they can photosynthesize. It's very likely that something similar also occurred in evolutionary history. So even this very rudimentary version of sight can be beneficial. You may ask, so why can't plants see? Well in some ways, some can. They can bend their stems and leaves to follow the sun as it crosses the sky. But as said before by Macroscopic, not much more than this is needed for modern plants, as sun is their major energy source and they don't otherwise move. But it is also advantageous for heterotrophic (organisms that get their energy by ingesting exterior organic material - aka, eating stuff) unicellular organisms to be sensitive to and move towards light as well - because that's where the photosynthetic organisms will be that they can eat. Again, even a simple version of sight can be advantageous. So what about another small improvement? perhaps being able to note when a dark patch moves through the light will allow these heterotrophs to move toward that dark patch as being a likely prey item. Simple but still advantageous. So sight develops, not because an organism "decides" to do so, but because those organisms with slightly better sight can find their food more easily and eat more, thus reproducing better/faster than those with slightly worse sight. Add billions of years and millions of mutations and you end up with sight as it is today.

Nerve impulses do not move at the speed off light. An electric pulse, and electric energy, is not the same as light energy. A nerve cell, or neuron, at rest (not transmitting a signal) maintains an electric gradient; that is, the inside of the cell is more negative than the outside of the cell. When the neuron receieves of signal of some kind (whether it be input from your sensory cells or a signal from another neuron), this gradient changes dramatically. It happens very fast, but it's still not the same as the speed of light; it does take a few miliseconds. For more details about the mechanism check out this wikipedia article: http://en.wikipedia.org/wiki/Action_potentials It's pretty thorough.

Nicely put. I'll have to remember that.

The basics are that sometimes signals external to cells can trigger a pathway that will utlimately express certain genes that otherwise remain unexpressed. And if never exposed to those signals, the genes will never be expressed.

Well, as I said previously, it's hard to find cases of habitat loss alone. And since you disagreed with me, I tried. But animals don't live in bubbles, and extinction is complicated - I'm all the more convinced of it now. Though the Layson Rail case includes alien predators, those predators did not prey upon the rails themselves, but on the vegetation of their habitat, stripping it completely. Human caused, either way. Both the Colombian Grebe and the Bachmann's Warbler live in wetland areas which have been drastically reduced. Wetlands are particularly biodiverse areas, and have classically been targeted for destruction as in the past most people did not understand their ecological significance; they were considered gross and smelly swamps, and many were filled in. The Colombian Grebe most certainly suffered from predation, but the population was also attempting to survive in a tiny fraction of their previous habitat. I think any species in that case becomes extremely susceptible to any other perturbation. And for the Bachmann's warbler, it like most of the species in this list still lists some hope for finding it again. But I think a sense of pragmatism tells how how small that hope is, especially if there hasn't been a sighting for nearly 20 years. Farmer's may persecute the cuban Kite, but we don't know if that means they went out and looked for them and killed as many as possible. Probably, if one ventured near their farm, they shot it. And once most of the Kite's habitat was replaced with farm - well. I imagine that the Imperial Woodpecker was hunted for folk medicine for as along as humans have been living in that area - at least well prior to deforestation. It was only until habitat loss weakened the population that the folk medicine trade actually may have become significant. However you put it, habitat loss is bad. It's one step closer to extinction, with the next or previous steps involving predation, or pollution, or disease. I don't think one factor should get precedence over the other when it comes to conservation. However, I also understand that resources are limited, but at the rate habitat loss is going, I don't think it's one that can be forced to the backburner.

Well, the beauty of some viruses is that they already target specific tissues and/or cell types. Viruses have a "preferred" range of hosts for which they have been selected to target. And if viruses have a means of targeting cell types, then there probably will some day be a way to adjust that means to target the cells we want them to target. (Just used the word target(ing) five times! yerk.)

I think the biggest danger of habitat loss is making animals more susceptible to other contributing factors to extinction. I was looking up examples of birds that have gone extinct in the last 50-100 years (I thought more recent examples would probably be better documented) due mostly to habitat loss. And I did find some - but most of the species listed had habitat loss in combination with other factors. I didn't make note of most of them, as your original post asked for something with habitat loss alone mostly to blame. Turning away the majority of the examples I found for this reason seemed, to me at least, to lend support to my statement above. Either way, here are the examples I found so far; some you will find listed as Critically Endangered, Possibly Extinct, usually because there are a few strips of area left to be thoroughly searched, even though a confirmed sighting has not been made for years. Most list other threats to the animals other than habitat loss, but usually indicate that the most devastating blow was the habitat loss. Laysan Rail (http://www.iucnredlist.org/search/details.php/18083/all) Columbian Grebe (http://en.wikipedia.org/wiki/Colombian_Grebe) Cuban Kite (http://www.birdlife.org/datazone/species/index.html?action=SpcHTMDetails.asp&sid=30037&m=0) Imperial Woodpecker (http://en.wikipedia.org/wiki/Imperial_Woodpecker) Bachman's Warbler (http://www.iucnredlist.org/search/details.php/22927/all)

Exactly. And the honeybee has genes that "tell" it to work for the good of the colony, because the members of the colony have those same genes, so if the honeybee dies but in doing so saves other members of the colony who go on to reproduce, it has albeit indirectly ensured the transfer of its genes to the next generation. Genes that will again "tell" the next generation of bees to work for the good of the colony. That's the point of saving relatives. Relatives have some of the same genes as you. And in the case of many species of bee, sometimes almost all of them have the exact same genes as you. Isn't the definition of speciation the forming of a new species? You can't say species aren't a reality and then go on to describe reality using a term dependent on the existence of species. Just playin' the devil's advocate here. I understand what you're trying to say; but the idea of a species is a tool to help us better understand evolution, and I think can be applicable as long as it is understood that not all organisms can be defined as a finite species.

Clear cut examples would be great, but as Sayonara and I both said, extinctions are so complicated that finding a clear cut example other than a sweeping knock out of life from a volcano may be next to impossible. And for the same reasons, merely suggesting that some estimates of extinction due to habitat loss might be exaggerated is not enough to say that habitat loss is CLEARLY not significant. Especially considering the fact that the estimates may not be exaggerations at all when extinction debt is taken into consideration.