Paralith

A cell doesn't have empty spaces. Everything within it is in solution - in water. And I wouldn't call it a sphere, because cell shapes vary tremendously.

I know I'm coming to the discussion a little late, but I felt compelled to answer this accusation. Establishing clear semantics and terminology is not more important than understanding - it's essential to communication and discussion. Just look at what exploded when people started lobbing the word "intelligence" around. If all parties are not clear on exactly what the word intelligence represents, then misunderstandings will begin, and someone may think that you're saying something that you're not, and will begin to argue with you when you may in fact actually be in agreement when it comes to the heart of the matter. It's impossible to effectively communicate when you don't understand each other, and its easy to have misunderstandings when you're dealing with a complex, nebulous concept in the first place. And you should doubt that everyone will automatically know exactly what you're talking about when you use a world like evolution. You yourself said it has its own connotations in layman's terms, yet it has different connotations in scientific terms, and you are, after all, posting in a science forum. And even so, it often happens that people with a less complete understanding of the theory of evolution still don't have a clear idea on the exact scientific definition of the word and the process that it represents. Humans do not have an "intuitive comprehension of language;" a language is a complex communicative system whose particular rules and definitions must be learned. We may be predisposed to be able to accomplish that learning better than most other animals, but it still must be done. It is a (somewhat unfortunate) part of the complexity of the English language that one word can have multiple meanings depending on context. This is true even when you completely exclude scientific meanings. By forcing scientists to yield to the definitions of lay people, you won't be making the language any easier. And it will be to the detriment of scientific progress, as without agreed upon, clearly defined terminology, communication and development of ideas within the field would slow down significantly. It is a lot easier to say "quantum mechanics" than to have to apply a paragraph full of exact descriptions in layman's words every time you want to refer to a certain phenomenon.

Because there is no issue. No one is arguing that individual organisms do not exhibit purposeful, directed, goal-driven behavior. We're arguing that life, in general, has no more reason to exist than do rocks. Whether or not an individual rock can have purpose has nothing to do with it.

Yes. Once life begins, living organisms have the purpose of reproduction. But why should life exist in the first place? For that there is no reason. Sometimes. You are giving us humans a little too much credit, I think. We are more aware of our own motivations than other animals, but that doesn't mean we are always completely aware of them. A great majority of what you do has a genetic influence (and thus is related to survival and reproduction) to some degree or another, and for the most part you are not aware of that influence. So a baby not being conscious of why its performing a survival action is not that amazing of a thing.

A baby is subjected to environmental influences right from the get go. Its brain is constantly taking in information, learning and re-wiring itself. I wouldn't say that a baby is 100% instinct, either. It may be 98% instinct, especially for the first week or so of its life, but like I said, once it begins to experience the outside world, it begins to be effected by it. And instinct is never conscious. An instinct manifests as an urge, a need, a reflex. You don't think about it - at least, most animals don't. We humans are a little more inward-looking than most other organisms, so we may be more aware of our instinctual urges, but instincts aren't ever supposed to be knowable in the way you're describing.

Except a newborn child has a state of mind. It dislikes being ejected from the warm, safe womb. It wants to be warm again. It is probably hungry, and wants to feed from its mother. Its mind is by no means blank. Nor is it "blind to the ways of mankind." When ejected from the womb the baby bawls and cries, voicing its unhappiness to its caregivers, thusly giving its first recognizable communication seconds after being brought into the world. As the baby grows it will seek to be with other people. It will imitate the adults around it, as this is how it will acquire learned behaviors. You can't be "blind" to something if you're actively seeking it out. Now, this may have some truth, that life and purpose are related. Once life begins, individual organisms within their lifetimes can carry out many actions that are purposeful. My purpose now is to find food. My purpose now is to find a mate. My purpose now is to protect my young. An organism can have any number of proximal purposes. But I assumed you were talking about ultimate purpose, the reason why life came into existence, and why it continues to exist. For that, there is no reason. There is no plan for life. The only function of life is to create more life. It continues to exist because its function is to continue to exist. It began simply because it could, not because life as a whole was ever meant to fulfill some kind of ultimate goal.

If I seem to be stuck on anything, it is only because I'm trying to make sure I understand what you're saying. Which I didn't, and thanks to your clarification, now I have a better idea - though I'm still going to ask you again if I understand you correctly. So you are also going by the definition of authority as "an expert whose views are taken as definitive," though this is not exactly what you're describing, I think. You're saying that if I, as an individual, make an observation about the world - say, that peas are green - and I'm not sure if that observation is true, I will check with several people, and if they all also say, "Yep, them peas are green for sure," I'll be more likely to believe my observation is true than if just one person says, "Yes, those peas are definitely and inarguably green." Is that correct? So, to answer to your original question of why we give "authority" (which according to your description is the ability to make correct observations) to single individuals. We usually only do so when we also have additional evidence that this person knows what they're talking about and, in this particular subject at least, are likely to make the most correct observations. For example, I would much prefer to ask a doctor, and not a group of lay people, to make an accurate observation about the identity of a strange growth on my foot. In our culture we know that doctors spend lots of time in medical school learning how to do just this and have probably practiced this skill on many other people.

You are right, of course. I just think the only way tabula rasa might possibly apply is to experience. A baby might have all those reflexive instincts, but they haven't experienced heights yet, haven't experienced breathing yet - even though they already have a preprogrammed response for when they do experience these things.

That's why I said, when a child first comes into existence, not when a child is first born. Obviously the brain is active and probably gaining experience for some time before actual birth. At exactly what point during development it can be said that the child can begin to "exist" and to experience, I'll leave up to debate; I think science doesn't have a current consensus on that point, anyway. But you're right, in essence we agree with each other. I was just trying to describe the only way in which tabula rasa could possibly have some biological truth to it.

To be honest, I don't understand what you're trying to say. So authority means "the power or right to give orders or make decisions," in other words, if we "give authority" to someone, we are basically giving that person the right to be the leader. So you are saying that we (as in humans, I assume) give the right of leadership to groups more often than we give the right of leadership to individuals. Is this for certain? Where are you getting this statement that you're treating like fact? Did some study show this? And even if it is true that we think of groups as leaders more often than we think of individuals as leaders (which I kind of doubt), why does it necessarily follow then that it is a mistake, that it is wrong to think of individuals as leaders? Wrong in terms of what? In terms of what works best to get a group to achieve certain goals? You need to be more precise about what you're talking about. Right now it doesn't make much sense, at least not to me, and by the looks of things, not to many other forum members either.

Somehow exersize of needed skills and muscles doesn't apply to solitary animals? expressions of happiness for being in the environment you're meant to enjoy doesn't apply to solitary animals? Pronking, also called stotting, is often used a way to show off the animal's health and strength; look how high I can jump. They often do it when they sight a predator, to in essence say to that predator, "Hey, I'm am in really good condition here, see what I can do? I could outrun you no problem. Don't even bother." It's worth it to do so, because discouraging the predator with a few jumps is a lot easier on the animal than actually running full out to escape, let alone the stress they avoid. Now, as to this whole tabula rasa thing. When a child first comes into existence, it has no experiences, no memories. That much is certain. When a child first comes into existence it has a brain designed to understand and organize experience in a specific fashion, and genetic impulses that will motivate it to achieve various reproductively valuable goals once it starts to experience things.

I disagree. Fully grown animals can still play. Play can still be practice for valuable skills they will use elsewhere, exersize for skills and muscles that need to be kept in condition, as a way to from closer bonds within your social group. For the horse to run in a field may be an expression of its happiness, for they love wide open spaces, and they are meant to love wide open spaces because that is the environment to which they are adapted and which they function best in. And I've already addressed why we philosophize about and discussed things that seem unrelated to reproduction. Our ability to do so in the first place would be nonexistent without its relationship to increased reproduction. Our desire to understand, to know, to explore, is part of our instincts that go with our intelligence and our high flexibility as a species to exploit so many different environmental niches. And yes, even the search for a god, or some higher moral principle, can have its reproductive purpose. We are group living animals. The group that cooperates better than other groups will be able to procure, for all its members, better resources, and increase their reproductive fitness. But groups are vulnerable to cheaters - members who do not cooperate or reciprocate, but take advantage of other, more trusting members. Cheaters like this need to be punished somehow. But punishing them can be difficult. It may be physically dangerous to yourself, it may give you a bad reputation in the group, the cheater's family may come after you. But if you have a religion, if you have a supernatural god who deals out the rules and lays down punishment instead, no one individual has to pay the cost of punishing cheaters, and the group has greater motivation to cooperate and work together. These things are not conscious. No human or animal thinks to itself, "gosh, I better do this, because it might increase my reproductive success somewhere down the line!" We have urges, feelings, emotions, curiosities, genetic suggestions that lead us toward these beneficial activities. As humans we can choose to ascribe whatever motive we desire to the things that we do, and being conscious, intelligent animals, have more ability to do so than any other living thing. But to think that we are somehow above and free of our evolutionary history is simply incorrect. I thought the tabula rasa theory went out the window some time ago. Since it's not true.

Well, let's think about the definitions of "purpose." One definition is "an anticipated outcome that is intended or that guides your planned actions." Life has no anticipated outcome. This definition implies a plan, a design. Unless you are a theist, this is just not the case. Another definition would be "function: what something is used for." What is life's primary function? To create more life. It may seem like this discussion, and indeed many other aspects of human behavior, are unrelated to reproduction. But that is not true. The very reason why we have the ability to have this debate, the reason why we evolved intelligence and language, why we involved to be inquisitive and curious and inventive, is because these characteristics increased the reproductive success of our ancestors. Our genes motivate us to persist in activities like these because this is how we develop technology and ideas that give us a competitive edge, this is how we keep our brains sharp enough to successfully navigate the complex social group within which we will eventually find our mate and raise our offspring, etc etc. Most animals, and I think most humans, are not conscious of these genetic influences, so our personal motivation for why we do the things we do will usually seem different and separate from reproduction and natural selection - but ultimately, they are not. So even now, we are still following the only purpose that can reasonably be assigned to life.

No organism is "simply trying to survive." An individual organism's need to survive only persists as a method towards achieving an organism's true "need:" to produce offspring that can in turn reproduce themselves. Humans are no different. Though we may possess characteristics that are different from other animals, these characteristics, like the desire to survive, only came about because they increased our ability to achieve reproductive success. In the big picture of things, we are not that special. Our pleasure is also ultimately rooted in the characteristics that helps us achieve greater reproductive success. Pleasure is just a proximate purpose, not the ultimate one.

Yes, that's what we use, CO2 chambers. I haven't heard of the tail trick, but I've also heard of a method that basically involves popping their skull off of their neck. From what I know it's a method from back in the day, and again difficult to pull off. I'm pretty sure methods of this nature are now illegal.

Reasonably so, within species. There will of course be different alleles for some genes, which would be part and parcel of the whole description of the chromosome and its genes.

Then you'll be waiting a long time, because that data will not be available in completion until a great deal more research has been done.

I would go with a small amount of saline. You could probably get some from a biomedical research supplier, they usually offer sterilized versions of things. In general, I'd have to add my voice to those suggesting you don't do this. I greatly dislike the idea of people who don't know what they're doing sticking needles into their own veins. If anything, see if you can get find a friendly nurse to help you out.

There are some plants that actually do not respond to purely mechanical damage, and will only begin a defensive response if the damage is accompanied by a chemical found in animal saliva. This is an adaptation to prevent the waste of expensive defense compounds every time a leaf accidentally gets ripped. You should do some research and see if this is the case for your plants. If it is, you won't get any reaction at all by just cutting the leaves. I actually did a research project on "talking plants," and unfortunately there's not a lot of truly substantiated evidence for it. Most experiments involve unrealistic environments and/or amounts of the proposed "alarm" compound, so their relevance to real life situations is dubious. However, there is one well studied system of sagebrush (Artemisia tridentate) and wild tobacco (Nicotiana attenuata), where tobacco plants growing next to clipped sagebrushes displayed a significant decrease in herbivore damage compared to tobacco plants growing next to unclipped sagebrushes, presumably because the "alarm" compound given off by the sagebrush incited the tobacco to keep its defensive systems primed. However, they have yet to discern exactly what compound is serving as the "alarm" compound, and as far as I know, no other such system has been found. And I say "alarm," because the plant being chewed on isn't actually trying to alert its neighbors. It's not adaptive to give your competitors a helping hand. It's more appropriate to say that the "listening" plant is eavesdropping on its neighbors, and responding to the defensive compounds that its neighbors release when preyed upon.

Are you possibly thinking of reptiles? They also have a three chambered heart, but with a partial septum dividing the ventricle, which helps to keep the oxygenated and de-oxygenated blood separate. But both reptiles and amphibians have two completely separate atriums.

Looks like it was first used by kids in Namibia who didn't have access to glue or petrol to sniff. link the first part is basically the same as above, but after that they talk about the possible Namibian origin.

Well, I'm not 100% sure, but I'd imagine that the overall pattern is the same, one loop going through the oxygenation organ, be it the skin or lungs or both, and the other loop going through the systemic capillaries. I'm pretty sure that the double loop and three chambered heart is a defining feature of all amphibians.

oh, you mean this: http://www.blackwellpublishing.com/matthews/channel.html (a pretty nice animation) transport proteins are specific. they are designed to only allow certain kinds of molecules pass through them. because of this, it doesn't matter which ions are smaller. the transport proteins will only recognize the specific molecule they are meant to transport.

evolutionary.

there is a picture here that will help you visualize it. Basically, capillary beds in the lungs and skin lead to veins that join together and enter the heart. The heart then pumps the oxygenated blood from these two oxygenation sources to the capillary beds of the body (or systemic capillaries as they're called in the picture). These then lead back to the heart, which pumps the now de-oxygenated blood back to the skin and lungs. Amphibians only have a three chambered heart, so there is some mixing of oxygenated and de-oxygenated blood there.