"Real" ringworlds

[Primogenitor]

An easy one to start with then

Note: plants do have a circulatory system, its just different to animals, esp mammals. They draw water into the roots and this goes into long tubes all the way up to the leaves where it evaporates. As water evaporates it draws more up the tube by surface tension and capillary action, kind of like drinking a straw. As the water moves, nutients such as minerals are brought with it from the soil up to the leaves. Theres another system which goes the other way, but im not sure how that works.

The reason you need a cirulatory system is because of surface area/volume ratio. Above a certain distince from the outside the cells of the organsim cannot get to oxygen/food at a fast enough rate. This is the reason you dont have worms above about 1/2 cm wide, they get longer because that keeps the distance the same. You could have a worm 10 miles long, as long as it is no more than the critical width.
One way to get around this is to put air tubes reaching from the outside inwards. Then as long as no cell is too far from a tube, its OK. But they can ony be a certain length before diffusion doesnt work.
So the bottom of the tubes is filled with a liquid, many chemicals will disolve in water better than in air.
Something that can carry oxygen/co2 in it (heamoglobin like).
The ends could seal over with cells that can move the required stuff from the air into the liquid in the tubes.
The tubes could join up within the organism so that they can exchange liquid. However, its still moving by diffusion.
It could be pumped by the walls of the tubes contracting, like your throat when you swallow.
The same liquid could also carry nutrients, waste, hormone, anything that need to get to all of the cells.
Some of the cells in the middle of the tube network become better at pumping, so that those at the outside can become specialised into transfereing nutrients/gases into the liquid.
Voila, you have a proto-heart, a proto-blood, and proto-blood vessels.

Remember, at all stages it only has to compete with the previous stage. This is also not orthodox theory, this is just off the top of my head. It probably has several holes in it, but im sure they can be fixed.

Evidence:
Insects have air tubes going into their bodies.
I dont think fish have a heart (cos i know the gills evolved into it).
Plants dont need a pump to move water.
Many small organisms are just filled with water(n stuff).
In an embryo, the heart doesnt start beating for some time. Gets nutrients from amniotic fluid)
There are many liquid containing orifices, the mouth for example.
Arteries are partially contractile and muscle lined.

Next!

[Spoo]

I dont think fish have a heart (cos i know the gills evolved into it)

Fish have hearts. The gills "evolved into" lungs.

[Primogenitor]

My mistake. Ive just looked it up to confirm.
Fish have a two chambered heart and a single circulation (Heart->Gills->Body->Heart).
Mammals and birds have a 4 chanbered heart and a double circulation (Heart->Lungs->Heart->Body->Heart)
I got confused.

It is more basic than a mammal heart however, so it still shows that you dont need a complete mammalian heart to have a working circulatory system.

[ May 16, 2003, 19:18: Message edited by: Primogenitor ]

[Loser]

The argument of the eye, and the approach that Jack used with the circulation system, has a name. It is Irreducible Complexity, and it would disprove evolution if a case of it could ever be proven to exist.

There are a number of candidates for Irreducible Complexity status, and the eye is actually one of them. The problem with the eye is not so much that is competing with other eyes, but that even the simplest vertebrate eye, and a few invertebrate eye, is filled with a clear fluid. It is the formation of this fluid that has the potential to be a case of Irreducible Complexity. Without this clear, and non-living, fluid, the vertebrate-type eye is not possible.

Currently, however, we do not even understand how this fluid forms during the embryonic stages. One moment the entire eye-sack is filled with odd blood vessels, the next is filled with the 'human jelly'. The metamorphosis is not understood at all, Last I heard. It is easily foreseeable that once we understand how this process occurs during the development of every vertebrate life form on this planet we will better understand how it could have happened the first time.

Another example is the cilia. These organelles are constructs that require complex and perfectly configured elements to function at all. Without any one of these elements these rudimentary limbs would simply not function at all. To view matters in evolutionary terms, the whole construct would have had to spontaneously generate in a complete, if relatively simple, form, as there are no 'more primitive' Versions possible. To take away even a single molecule, or even a single atom from one of the constituent molecules, would render the whole apparatus not less efficient but totally nonfunctional

Almost all cilia are made of the same clever molecule, though sometimes (as on the humane sperm) the same structure is repeated on top of itself numerous times to increase the strength of the whip. But this matter has only been studied for a few decades, and you can't hold it against science if the scientists don't figure out everything right away.

There are a couple other contenders for Irreducible Complexity status, but just because they might be irreducible does not mean they are. Give it time, science will pin it all down, even the things it has gotten wrong so far. But when you start questioning scientific theories, you need to use science to challenge them. build a hypothesis, test it, publish it for your peers, respond to their criticism.

Or, of course, you could always just engage in energetic discussions, like this one. They're Grrrreat!

[Jack Simth]

Originally posted by Primogenitor:
It is more basic than a mammal heart however, so it still shows that you dont need a complete mammalian heart to have a working circulatory system.

I'm confused - where did I specify mammilian? Even worms have hearts, blood, and veins (of a sort).

Edit: Point of fact, I seem to have even specified that I wasn't just talking about mammals:

It appears to be required for any non-plant that is bigger than a few cells

[ May 16, 2003, 22:22: Message edited by: Jack Simth ]

[Jack Simth]

Originally posted by Loser:
Give it time, science will pin it all down, even the things it has gotten wrong so far.

Just because it might be possible to "pin it down", doesn't mean it is possible to pin it down (to paraphrase yourself). Making that leap (as you appear to) is an act of faith.
Creation theory can readily explain such irreducibly complexities right now while, at present, evolution doesn't seem to be able to. Yet you seem to believe that evolutionary theory is a better explanation of such things. This is a very curious leap of faith on your part.

[Krsqk]

I think the problem with most of these debates was alluded to further down in this thread and discussed quite a bit in the Plato's Pub thread a few months back. Any data (not evidence--see below) we can present can be fit into almost any hypothesis with a minimum of difficulty. Because no one is offering their theory as the "We-have-all-the-details-worked-out" theory (ok, no one who can be taken seriously), it's fairly simple to reinterpret the data to fit your pet ideas.

Probably the biggest hurdle to obtaining true "evidence" is our very limited scientific understanding. Some have estimated that the invention of the computer has allowed us to understand 22,000 years' worth of research in this century (in pre-computer years)--an improvement of 220 times--but all it has done has demonstrate our lack of understanding. Each new advance opens up a new level of complexity which must be studied, and it takes decades before we can be said to have a grasp on a new field of study. We will have no real "evidence" until we reach the informational limits of the complex world in which we live. Obviously, we need to build a Central Computer Complex III to speed things up.

My other peeve with this issue is not one with the real reasoned debaters, but the psuedosciencemongers (did I just invent a new word?). At least in popular media, evolution is portrayed as a scientific hypothesis against alternate supernatural hypotheses. Evolution is not scientific, but naturalistic. The issue is usually one of competing worldviews, not one of science and myth.

[edit]The distinction between scientific and naturalistic is important because most people think evolution is scientifically provable while recognizing that creation is outside the realm of science. The only "scientific" means of proving macroevolution is to observe it (requiring long periods of time), which still would not prove it as the means of species origination.

Also, I don't buy into the currently popular "Evolution has nothing to do with origins" mantra. Micro-evolution has nothing to do with origins, nor is it much disputed(although I think the terminology is unfortunate--adaptation worked quite nicely, thank you). However, when one says "Microevolution, ergo macroevolution," one is dealing with origins and hypothesis. Unless, of course, one wants to Fyronize the word origin to mean "the origin of the first life form" instead of "the origin of all life forms." It's always helpful to know exactly what we're saying here.

[ May 16, 2003, 22:37: Message edited by: Krsqk ]