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LWN.net Weekly Edition for May 23, 2013
An "enum" for Python 3
An unexpected perf feature
LWN.net Weekly Edition for May 16, 2013
A look at the PyPy 2.0 release
Experimenting on the BSDs
Posted Nov 15, 2012 8:26 UTC (Thu) by man_ls (subscriber, #15091)
Posted Nov 15, 2012 16:36 UTC (Thu) by khim (subscriber, #9252)
But what does it change? Decade ago *BSD had tons of advantages over Linux, but they all concentrated on smaller niches and eventually Linux caught up. Linux is still not on par in select few niches, but their number is dwindling.
At some point is stops being feasible to support the whole separate OS just for these few separate narrow niches.
Posted Nov 19, 2012 9:16 UTC (Mon) by ortalo (subscriber, #4654)
Ok, that's probably a form of subsiding, helping or something like that. And then?
If one has to choose between evolving Linux into a shark or a dolphin; my choice is taken. (And, by the way, there are already plenty of sharks in the sea, may not be so safe in the long run.)
Posted Nov 20, 2012 9:49 UTC (Tue) by mpr22 (subscriber, #60784)
Posted Nov 20, 2012 12:01 UTC (Tue) by man_ls (subscriber, #15091)
Posted Nov 20, 2012 17:32 UTC (Tue) by viro (subscriber, #7872)
 in fact, human eyesight is amazingly good for mammals - more or less on par with medium-sized eagles; still losing to big ones, but not by much. Most of the mammal species are nowhere near that resolution. Horse is about 4 times worse, cat - about 10, and those are relatively good. Anthropoids are very unusual in that respect - we'd managed to re-evolve fairly decent eyes. We even got part of the colour vision back; still only 3 receptors instead of the normal 4, though ;-/
Mammal evolution, literally
Posted Nov 20, 2012 21:39 UTC (Tue) by man_ls (subscriber, #15091)
In fact adaptation to different ecosystems is the only measure of success that we may objectively use. We might focus on how our group of previously dwarvish creatures (less than a metre long) have invaded almost all ecosystems, often becoming their apex predators. Birds have not colonized the seas, for example, other than flying above them; and yet they have a whole continent (Antarctica) to them.
If we follow this line of reasoning, we might argue that bacteria are the living champions and that we should devolve to single cell organisms, since we have 10 times more bacterial cells in our bodies than human cells...
But the particular thing I had in mind was that crazy habit of laying eggs around and then abandoning small birds to their luck after at best a few weeks. This is way better than fish just lying eggs around, but much worse than our viviparous system. By "evolving into mammals" I was specifically thinking about breast-feeding their offspring, which allows us mammals to create affective bonds and teach every new generation the old tricks. That is the indubitable advantage of primates which humans have taken to an extreme, by living several decades with their parents.
So our friendly penguin-like operative system should evolve towards the breast-feeding dolphin and not backwards to the offspring-eating shark, even if some of them are viviparous.
Posted Nov 22, 2012 7:25 UTC (Thu) by viro (subscriber, #7872)
As for vivipary vs. ovipary... Archosaurs use the eggshell as calcium store for embryo, so they are pretty much locked into using hard-shelled eggs. Which has very little to do with the amount of time newborns spend in contact with parents; precocious mammalian species can have the contact ending very fast and "few weeks" is nowhere near the longest you can get with birds.
The only measure of clade being successful is its survival; scala naturae is an artifact of the way we use mnemonics to turn messy and complicated history into something that can be easily remembered, as long as you don't look into details...
Posted Nov 22, 2012 9:56 UTC (Thu) by man_ls (subscriber, #15091)
The resolution each species you have mentioned has is -- what it needs to survive. Or more specifically: the lowest resolution it can get away with. Birds of prey need to locate their victims from a long distance; primates need accuracy to locate tree branches when they jump. Note that horses have better eye resolution than humans overall, but do not have a central fovea with increased accuracy.
The fact is that longer development periods are present in mammals than in oviparous animals. Even marsupials have to support their offspring for a certain time before they are ready -- not so with the more primitive monotremes. I think that breasts and milk are great advancements that have allowed mammals to thrive in many environments and in harsh conditions -- for example allowing the mother to feed their offspring even when the environment is bare.
I am not trying to establish a single scale from bacteria to humans; each species is almost by definition well adapted to its environment, or it will perish. Adaptations are always amazing: albatross have a gland to secrete excess salt so they can drink sea water, condors can reportedly fly up to 10 km high, penguins thrive in the Antarctic.
But there is a measurable degree of change, or divergence from the original form. There are many species which have survived unchanged during hundreds of millions of years. Mammals, primates and humans have evolved a lot from the time of dinosaurs, changing not only morphologically but also biochemically. For a simple example compare elephant trunks, dolphin tails, bat wings and human hands. While most birds are still very similar to their dinosaur ancestors in their basic shape.
Posted Nov 22, 2012 15:40 UTC (Thu) by raven667 (subscriber, #5198)
Unlike the pop aphorism "Survival of the Fittest" the real world is more like survival of the fit-enough.
Posted Nov 23, 2012 11:58 UTC (Fri) by dgm (subscriber, #49227)
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