Giles

The trick will be designing a society in which competition is a purely positive thing. With respect to certain resources in certain nations, we are already approaching the situation that fafalone describes.

Generally, higher capacity, redundancy and safety margins are better - you can't win a marathon on one lung. You think about exercise when you need to exercise, and it prepares you (think how useful this would be in predator-prey interactions.) Your immune system can handle more diseases than it will ever encounter. You can survive injuries. I suspect the amino acid code is a matter of chance in some degree. once you've got one you can see how hard it would be to change. Nevertheless it does vary to some extent. There are also certain likely pressures on it. It should be mentioned it's not exactly the same in all organisms, but it's always three base pairs to a codon. There are more than four bases though, if not more than four at a time, and more than 20 amino acids. it's probably at least partly a matter of stability. A redundant coding system is more stable in the face of mutation (please note that natural selection favours a LOW rate of mutation in the short term - higher organisms have other ways of generating variation). Conversely, four base types is more concise than two (2 bits/pair rather than 1). Because of the way pair matching is carried out, another base with similar chemical properties to an existing one would be a liability. Your post seems a little confused. Life is no as concise as it could plausibly be with a similar underlying chemical structure; nor is it very long-winded (unlike me). Finally, it shows signs of being constrained by past design. I'm not sure there's much problem for evolutionary theory in that. I think we both need to learn more biochemistry to discuss this with confidence.

It's hard to speculate about what organisms 'need'. After all, you only need less than half of your lung capacity to survive. Another problem is that characteristics have to arise through adaptation. That means they have to fit the enviroment. There are few characteristics so specialised that they would be completely useless in an enviroment that the organism could survive in. Nor are many organisms likely to experience such a drastic, unexpected change in habitat in one life time.

If a gene is no longer under selective pressure it will tend to mutate into uselessness over time. This includes the part of the genome that controls its expression. This is what a lot of junk DNA is. You can't discriminate species over time meaningfully; there is no distinct cut-off between a population being of one species and it being of another due to evolution.

History of science and philosophy of science are inextricably linked, which is why i suggested it as one forum in the first place. I do think we should keep this site as a science specialist though. I would say, history is also academically pretty rigorous, it's not so far from science. Philosophers and scientists were pretty much the same thing ('natural philosophy') until recently.

He's right you know. hard going for us non-physics people tho.

(Since MrL ain't here yet... ) Red, Riley Hobsen and Bence is pretty much the cambridge course in book form, since it's written by three cambridge lecturers. Hence its usefulness.

You'd need three giant computers to help you run the world, much like whichever giant robot anime it is with the ever more scetchily drawn existentialist ending. Either that or multivac and a coin (obscurity ahoy!) Then the computers could get on with it, and you could get on with building a ridiculous throne room. And employ stephen fry as butler called jennings-smythe.

I think the -1 decribes the position of the base relative to the start of the exon, i.e. one base towards the 5' end of the mRNA strand, certainly within the scope of the splicosomes activity. This fits with these mutations causing most of the incidence of the disease. At face value "the 5' half" would mean the half of the mRNA strand closest to the 5' end. It would make more sense for it to mean the 5' end of each exon, but that could just be me jumping to conclusions. Most of my textbooks are still in Cambridge, so i can't check until sunday

This is in a eukaryote, right? In any case i'm having trouble with it as well, even though i know what all the words mean. can you quote any more of the source?

That's really interesting. Following the links, though, it looks like the author's personal hobby horse, which always inclines me to be skeptical.

They may be different but they're hardly unrelated. Obvious example, read popper and kuhn.

W is watt, i.e the unit of power (energy per unit time). I can't remember what 1W is in joules/second. m^-2 is 1/(metres squared) so it's power per unit area.

could you be more specific or give a source?

I didn't. I just thought it would confuse the issue.

Contemporary possible 'intermediate stages' in 'bacteria sex': 1. Transformation and plasmids. Bacteria can take up and release small loops of genetic material called plasmids, and while inside the bacterium these can be treated as part of its genome, and even reproduce with the cell. A bacteria that takes up a plasmid is said to be 'transformed'. 2. Conjugation Certain bacteria have external structures called pili (from the latin for spear). When the pili of two bacteria of the same species meet, if certain other conditions (chemical signals etc.) are met, the two fuse, and the cytoplasms of the two cells become continuous, allowing plasmid exchange. 3. F+ and F- e. coli (I think that's the right terminology). A certain Eschera coli plasmid will lead to conjugation when one cell with it and one cell without it come into contact, the F- cell being transformed to F+ when it receives the F plasmid. This is not unlike having two sexes. So it's not that hard to see how single-celled organism might have acquired sexual characteristics. Unfortunately its hard in the fossil record to see what actually happened. There is an intermediate stage between being unicellular and multicellular - so called 'colonies'. Famous example is the portugese Man o'War 'jellyfish'. Another type that has made waves recently is slime moulds, colony organisms formed by eukaryotic unicellular organisms under conditions of food scarcity. With one of these incorporating something like the 'sexual' bacteria, you can see how specialist structures would be favoured much as they were for every other function. Transformed components could then begin to form another organism, which of course encourages wombs an so on... This raises the question of the two physiological different sexes we have. This is a question of 'evolutionary stable strategies'. If the two sexes make a substantial contribution to the young's survival, there is an advantge to be had making a smaller contribution to more offspring. You would get an 'arms race'. Furthermore, this would encourage other differences because if two individuals made a low contribution to the offspring's survival it would probably die. This also raises the pressure for the highly contributing parent to contribute even more care, and eventually the situation polarises. So you have division into male (contributes sperm) and female (contributes egg and care), and both sexes avoiding mating with themselves, until eventually they can't.

what about suggest a 'history and philosophy of science' forum? at the moment that sort of thing would go under 'metaphysics and pseudoscience' which excludes quite a lot. or there's GD i guess.

No one is sure yet what constitutes 'conditions for life', nor do we know quite what the chemistry of every part of prehistoric earth was like. So we can't actually tell how likely life (even just the 'RNA world') was, nor how quickly (compared to expectations) it arose. we need to be careful not to ignore the anthropic principle. life may have had only a few hundred years to appear on hundreds of billions of earth-type planets. a cell's life cycle is measured from the reproduction that produces it, until it divides itself. change 'cell' to 'organism' and all is well tho.

Whales may not have had the opportunity to develop gills; they've only been down there about 60 million years. bear in mind how long it took to get out of the water in the first place. brains are very expensive organs (yours uses about 20% of your oxygen supply). patterns can emerge in design due to developmental mechanisms as well - each cell just following a simple local rule. It's easy to imagine a spiral forming by this sort of mechanism.

Because the arguments in question have become so bogged down as to be indigestible to the general public (gould's last work on the subject was 1500 pages of impenetrable prose, which he needed proffessional philosophers to help him write), no one is making exciting new claims, and there haven't been any eye-catching experiments. In any case, gould and his cohorts are not really so far from the strict neo-darwinists. If anything, the press tend to exagerate the contrast (as did gould himself).

(Molecular) cladistics gives the most parsimonious phylogeny. The odds of molecular convergence (as opposed to conservation) across a lot of characteristics are pretty low.

Biogeography: An evolutionary and ecological approach The Master and Margarita by Mikhail Bulgakov The Law of The Peoples by John Rawls The Structure of Scientific Revolutions by Thomas Kuhn Principles of Development by Wolpert et al.

We don't have a purpose in the sense that one our tools has a purpose - the sense of being created for a purpose. rather we can decide a purpose for ourselves. and we've got quite far by doing that. we might not be physically big, but that's a rather crude value system. not many supernovae have the equations for their own demise.

I'm not sure how you would measure the speed of a 'thought'. In nerve signalling, all the important stuff is taking place by transfer of ions or signalling molecules across membranes. This transfer is carried out by proteins in the cell surface membrane (remember an enzyme is just one kind of protein). Action potentials do travel more rapidly along axons with a larger diameter, i.e. a larger membrane area/unit length. A larger membrane area means (I assume) more protein 'pumps' or 'channels' , so I think you are correct in this limited sense. (more on nerve signalling here: http://faculty.washington.edu/chudler/ap.html http://faculty.washington.edu/chudler/synapse.html)