Peez

I don't think that anyone is suggesting that any traits provide "any advantage to the long term survival of homo sapiens [sic]". Evolution by natural selection works (generally) through the survival and reproduction of individuals, not species.If you mean Homo sapiens, then no. The evidence suggests that we have been around for a few hundred thousand years at most.That is an interesting assertion, do you have any reason to think that it is true?Nobody is trying "to endow these traits with super-survival powers." All that some are suggesting is that some of these traits may have conferred an advantage with respect to survival and/or reproduction.It is interesting that you are comparing the "survival" of large groups of organisms to that of one particular species. Note that there is no reason to suppose that living bacteria are members of the same species that were found billions of years ago. That being said, there certainly are many species that have (so far) endured much longer than we have. This is not relevant to the topic at hand.Probably not.

Peez

ps418

And it need not even be a strong advantage. In a given environment, every trait is either neutral with respect to fitness, or has an arithmetic mean advantage or an arithmetic mean disadvantage. Unless the arithmetic mean effect of a trait on fitness is null, there will be some selection one way or the other. (Of course, this involves idealized assumptions, such as that traits vary independently of each other, that often will not hold in the real world) In any instance, including hairlessness, it may (or may not) be the case that the net fitness advantages of hairlessness just barely outweigh the disadvantages.

Patrick

Oolon Colluphid

Yup. And though someone else can be more specific, I’ve read somewhere that even tiny degree of advantage -- something like 1% -- can spread through a population in X (surprisingly small number of) generations.

Oolon

Nic Tamzek

ps418 wisely writes,

Eh, good point. I was just trying to think of a way to gather novel information in this particular instance, since the common sorts of evidence (present usage, ecology, etc.) seem to be inadequate in the hairlessness case. There could be e.g. some evidence regarding the time that it occurred, and if it was fixed due to strong positive selection.

Regarding fur protecting from flies and mosquitos, I actually don't know squat about it. However it seems possible that there is a bit of an arms race, and that while present fur isn't perfect protection, it's far better than nada. If you think of bears, apparently their fur is thick enough to prevent bee stings everywhere except their nose. For buffalo etc. it's probably a combination of tough, coarse hair plus a tough hide.

We need an ectoparasitologist...

ComestibleVenom

pz,
I find it very hard to believe that it would be possible to make any progress in understanding human evolution if we couldn't make plausible working hypotheses around which evidence could be provisionally interpreted. Waiting for ironclad proof of every candidate element in a theory of human evolution would be a sure recepie for being unable to come up with any interpretation of evidence we do find.

That being said, I can obviously see the need for being clear on the status of such hypotheses.

ps418

Depending on the heritability of the phenotype, of course, as well as the fitness of the all the other phenotypes, if any, that it is genetically correlated with.

In the War of the Fitness Maximizers, I suspect there are very few slam-dunk solutions, and lot and lots of ad hoc compromises where the fitness advantages of a phenotype just barely outweigh the disadvantages.

Patrick