Undertoad Saturday Mar 9 03:24 PM3/9: "Lucy" artist's reconstruction
This is "Lucy", based on the famous Ethiopian discovery found by archaeologist Leakey. This week the Brit science journal <i>Nature</i> published details of an analysis which promises to tell us much more about human evolution. It tells us that modern traits of humans first showed up in Africa 130,000 years ago, and then expanded outside of Africa about 90,000 years ago. It also tells us that the original line evolved and did not go extinct.
I wish I knew more but <i>Nature</i> wants $25 to read the damn article... proving that evolution has officially stopped.
narkosys Saturday Mar 9 04:45 PMis this based on an artists rendering? or did they actually take the time to reconstruct the skull and use forensic artists to build the face?
narkosys
Undertoad Saturday Mar 9 06:00 PMI don't know! The rendering came from the French Yahoo News so even the French translation wasn't any help.
Somewhere around here I have an australopithecus (sp??) reconstruction of a face only, and it is the creepiest thing you'd ever want to see. If I can find it, I'll make it tomorrow's IotD.
Undertoad Saturday Mar 9 06:05 PMOK, it's Homo Erectus that I have the reconstruction of, and it WILL be tomorrow's image.
Nic Name Saturday Mar 9 07:23 PMHomo Erectus again?
Undertoad Saturday Mar 9 09:56 PMA better one. Just you wait.
juju2112 Saturday Mar 9 10:10 PMHomo sapiens did evolve around 120,000 years ago, but Australopithecus afarensis (Lucy) is actually 3.2 million years old.
Lucy was very controversial because the discovery basically proved that hominines walked upright as far back as 3.2 million years ago. Her brain was not much bigger than a chimp's. So, basically, we evolved our upright stance long before we evolved intelligence.
Nothing But Net Saturday Mar 9 10:10 PMWell, today we have 'Lucy erectus'. Is tomorrow's IotD going to be 'Desi erectus'? :p
juju2112 Sunday Mar 10 01:29 AMHere's an actual pic of Lucy; about 40% of the skeleton was recovered.
Check out the femur.. see how it's angled towards the center of the body? That helps the hominid keep it's balance when standing. You can tell an amazing amount of things from just a few bones.
This pic is kind of a hodgepodge of different clues to bipedality.
The coolest part of it all I think are the hipbones. Check this out.
In order for humans to retain their center of balance when standing, they have to have a small birth canal. This forces babies to be born much earlier than normal so the head will be able to fit through the pelvis.
So, since human babies have only a very small percentage of their brains when born, they are completely helpless when born. This results in extremely long maturation rates compared to other animals. Also, since the baby is out of it's womb, it's brain is subjected to constant stimulus while growing -- resulting in higher intelligence. Not to mention the fact that the brain is now free to grow to be as large as it needs to be.
Nothing But Net Sunday Mar 10 01:54 AMjuju2112...
Do you work for the fucking Discover Channel?
juju2112 Sunday Mar 10 01:57 AMlol... no, I just happen to be in a human evolution class this semester. :]
But anyways... I think it's cool. If it weren't for us standing upright, we probably never would have developed intelligence.
Nothing But Net Sunday Mar 10 02:14 AMIt is a well known fact that human males lose most brain function while in a reclined position, especially when there are reclining females in proximity.
Count Zero Sunday Mar 10 10:37 AM
Quote:
Originally posted by juju2112
So, since human babies have only a very small percentage of their brains when born, they are completely helpless when born.(...)
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An interesting fact is that the human brain has a fixed number of neuron cells... So the difference between a baby's brain and an adult's is not structural.
Actually, when you get older your brain cells start dying. So an average baby has a bigger number of neuron cells than an average adult.
Bitman Monday Mar 11 04:44 PM
Quote:
Originally posted by juju2112
In order for humans to retain their center of balance when standing, they have to have a small birth canal. This forces babies to be born much earlier than normal so the head will be able to fit through the pelvis.[/b]
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I thought our 9-month cycle was actually longer than other animals.
sapienza Monday Mar 11 09:02 PMWell, I think he means developmentally earlier. Pull a kitten out of its mom and it'll be walking around and functional within a few weeks. Pull a human baby out of its mom and it's just a little eating/shitting machine for the first few years!
'Course, I shouldn't presume to speak for him ....
dude123 Tuesday Mar 12 10:58 AM
Quote:
Originally posted by Count Zero
An interesting fact is that the human brain has a fixed number of neuron cells... So the difference between a baby's brain and an adult's is not structural.
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I would say that that means that the difference is entirely structural - it's the connections between neurons that change, not the number of neurons. See this article. The number of connections doesn't necessarily increase, but the "right" connections are formed, which means you get smarter.
Also, hasn't very recent research shown that we actually can make some new neurons as adults, at least under some conditions?
juju2112 Tuesday Mar 12 05:49 PMPerhaps I misspoke. I was just relating what my teacher had said and I guess i misinterpreted what he meant by "brain growth". It looks like you're both right.
Neuron content aside, though, if the baby is born any later on in its physical development, the head won't fit through the pelvis. The brain being subjected to constant stimulus earlier on in its devleopment seems to be important, as intelligence is somehow related to the connections between the neurons, which are formed during the first three years after the baby is born.
Anyway, computers are definitely my specialty, so i'm really not an expert on this. But this class is just so awesome that I just had to share some of the theories with you guys. :]
(decent link showing you're both right: http://www.growingchild.com/brain.html )
Your reply here?
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