Zombies, Klendathu and The Absurdly Violent Intergalactic Space Fungus.

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Originally Posted by grimmas

Granted but I was more commenting on the time these things take for any noticeable effect. I thought the height change was more to do with improvement in nutrition of the last century rather than natural selection?

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It's both. From memory I think it's about 3/4 nutrition and 1/4 genetics, but it's definitely partly evolutionary. Although scientists haven't nailed down WHY: it could be as simple as sex selection, or it could be that tall genes occur alongside some other beneficial mutation.

Under the right pressure adaptions can show noticeably within a few hundred years (ignoring really sudden stuff like the Black Plague) so there would definitely be some over ten thousand. But without being able to compare the two they may be harder to spot.

It'll be cause it helps you reach the pedals in the car better, and if you're too short you can't jam the brakes on as hard. Natural selection in all it's glory.

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Originally Posted by Morgrim

It's both. From memory I think it's about 3/4 nutrition and 1/4 genetics, but it's definitely partly evolutionary. Although scientists haven't nailed down WHY: it could be as simple as sex selection, or it could be that tall genes occur alongside some other beneficial mutation.

Under the right pressure adaptions can show noticeably within a few hundred years (ignoring really sudden stuff like the Black Plague) so there would definitely be some over ten thousand. But without being able to compare the two they may be harder to spot.

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Cheers Morgrim I was making the mistake of thinking the adaptations needed to be permanent and forgetting It is very gradual process and that every adaptation doesn't result in a new spieces. You'll have to excuse me the biological texts went away after Uni(worryingly quite a while ago now). Always nice to brush up though.

Another point about evolution is that it can only improve, rather than create.

I.e., the human eye is descended from the same design lineage as fish eyes, the same as most other animals. However, it's actually not that great for seeing on land, there are better systems that could be used. Evolution can't make these systems just appear, though, it needs the creatures with the weaker systems to die without breeding so that the ones with the better system prosper and propagate. Since most creatures on land use the eye in mostly the same design pattern, there's no real imbalance in evolutionary advantage that has ousted it.

It's like the evolutionary equivalent of the Sherman tank. Not the best by practically any means, but good enough for the job.

?
Whats the issue with the eye and how could it theoretically be better?

The eye is filled with liquid, which was an evolution that allowed it to see in water without refraction, giving it greater clarity. However, it now suffers refraction because this fluid still exists and is necessary to basically keep the eye's shape, but we're looking through liquid into air.

Apparently this contributes to the limited range of vision, and depth of field problems eyes typically have.

Neil Degrasse Tyson explains it better than I do in his Cosmos series. Episode two if I remember correctly.

That makes sense, enough of an explanation for me anyway.

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Originally Posted by Morgrim

It's both. From memory I think it's about 3/4 nutrition and 1/4 genetics, but it's definitely partly evolutionary. Although scientists haven't nailed down WHY: it could be as simple as sex selection, or it could be that tall genes occur alongside some other beneficial mutation.

Under the right pressure adaptions can show noticeably within a few hundred years (ignoring really sudden stuff like the Black Plague) so there would definitely be some over ten thousand. But without being able to compare the two they may be harder to spot.

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I'm sure I read that the whole 'we're getting taller' thing was a myth?

Though I could be confusing it with average heights only ever going up. I dunno. I can't cite any sources, because I can't remember where I read it?

I'd say based on doorways being built to allow you to pass through them, we're getting taller.

Maybe I am confusing it with average heights only ever going up.

I know the Roman Empire considered my (possible) Pictish ancestors to be massively tall, and the graves from northern Europe around that time don't suggest they were short?