orpheus last chant

just a short question....what do you think we are evolving into....i always thought that (if we don't nuke ourselfs into nuclear winter and die, or poke the ozone layer with enough holes to suntan urselves to death) we will get even bigger heads, taller foreheads.... feet get smaller, mouth even more hairless, and start lookin like (strangely) the homunculus in our brain... well except for the ears....

Jinto

Not likely. What humans will evolve into depends purely on what selective pressures are exerted on human beings, and has nothing to do with following current trends. While increased hairlessness (aside from our heads) may become more prevalent due to sexual selection, I see no pressure for any of the other traits you described.

Elvithriel

The next step in human evolution is by our own hand.

ps418

To emphasize Jinto's point: are people with bigger heads and smaller feet achieving greater completed fertility than those with smaller heads and larger feet? If you want to know what humanity will look like tomorrow, that's the kind of question you'd want to answer.

Patrick

orpheus last chant

i was only mentioning those stuff because over time we did become less hairier than our ape ancestor (so i thought this will go on) .if over a period of time we use less a certain part of our body (like feet because we have cars and etc.) won't that turn them into a sort of apendix....

same way as our head became bigger over time (up to 1500 cm2) won't that continue....?

does evolution depend only on selective breeding?

Oolon Colluphid

Pretty much. The crucial bit to grasp is this. Evolution by natural selection is based on differential survival and reproduction: some organisms are better endowed by inheritance to leave descendants than others. And their ancestors in turn were better endowed by their parents, and so on.

So if an environment shifts so that some feature (a novel accident or otherwise) becomes more useful, then any enhancement of that feature will spread through the population, and the population will have evolved. (It’s populations, or more specifically lineages, that evolve, not individuals.)

This is why it is difficult to say in what ways if any we humans are evolving, at least in major ways. We are so in control of our environments. We may well -- indeed I suspect we are certain to -- continue to evolve in relation to parasites an pathogens, for there is room for natural selection. But even there, medicine can potentially outstrip the pathogens, allowing many to survive who would otherwise succumb and so not pass on their heritable lack of resistance to the pathogen.

Now, if we were to put a population on an island, allow no outlander interbreeding and provide them all with motorised wheelchairs... then shoot anyone who walks (especially the young) and encourage only the wheelies to breed... then after one hell of a lot of generations their legs might be found to have reduced.

But that thought experiment reveals the problems. We interbreed through travel, and engage in a wide range of activities. The genes for less leg muscle and reduced femur will not remain on the island. Instead, within a generation or two they can find themselves in a suburban schoolkid who is simply not good at sport. If the culture prizes sportsmen (or the merely fit and active), then those same genes that on the island were an advantage in the genetic-legacy stakes could be a disadvantage in their new environment.

So the genes that enable a mountain-climber to exist on less oxygen may find their way into his grandson, a sea-level-living couch potato.

And a real-life example: the sickle-cell allele that confers malaria resistance can (has) found itself widespread in malaria-free Americans, and not just African-Americans, and leads in a double-dose to sickle-cell anaemia. Formerly, most of those with the disease died before reaching adulthood. That is, died before leaving any descendants. But with medical treatment, their legacy can now be passed on.

Future directions? Increased brainpower? Not necessarily, we have computers to think for us in many ways, and it depends on what we’re trying to think about, which is vastly varied. And would it be enough to produce differential breeding success?

Increased... oh, I dunno... dexterity (ref keyboards)? Only for those in an environment containing such things, and their genes can be shuffled into bodies of others in completely different circumstances. And again, enough of an effect to limit breeding?

Decreased body hair? Only through sexual selection, and that is so open to cultural influences -- and there is such a wide range of tastes out there (try any large porn links site, you won’t believe what some people find attractive... and they probably wonder at one’s own tastes) -- that this too seems unlikely.

In short, this side of something really major that re-introduces natural selection (the first colonisation of Mars, perhaps)... or some pretty odd and vastly widespread cultural causes of reproductive selection... we are too homogenised a species, and too non-specialised a species, for evolution to take us in any predictable direction.

Cheers, Oolon

BigBadShrubbery

Just two quick questions:

Why Homo? Wouldn't Pan be better?

Why Sapiens? Humans aren't really that wise.

Craig

That's kind of how I've always thought too, until we start having smaller groups of humans isolated somewhere we probably aren't going to change a whole lot.

It's way too easy (now) to survive and reproduce for both those with advantages and those without. We've conquered natural selection pretty well, as evidenced by our huge numbers.

orpheus last chant

why homo and sapiens...that is our name duh....

homo sapiens sapiens

Non-praying Mantis

For that, you'd have to ask Karl Linnaeus, he's the one that came up with Homo sapiens.

NPM