Upright Humans Came Down From Trees, Not Up From Ground

Galvasean

While traditionally many scientists believed that humans evolved to walk upright from a type of ape which walked on the ground using it's knuckles, a signiicant amount of evidence has emerged to show that we in fact inherited our upright walking trait from a tree dwelling ape.

A detailed examination of the wrist bones of several primate species challenges the notion that humans evolved their two-legged upright walking style from a knuckle-walking ancestor.

The same lines of evidence also suggest that knuckle-walking evolved at least two different times, making gorillas distinct from chimpanzees and bonobos

Full article here.

lostexpectation

so when did "we" get up into the trees

Galvasean

lostexpectation wrote: »

so when did "we" get up into the trees

About 260 million years ago apparently:
http://dsc.discovery.com/news/2009/07/28/first-tree-dweller.html

Suminia getmanovi

lostexpectation

is there some eolvution of man type diagram of the animals getting bigger and more ape like up in the trees

http://scienceblogs.com/laelaps/2009/07/suminia_life_in_the_trees_260.php

Galvasean

lostexpectation wrote: »

is there some eolvution of man type diagram of the animals getting bigger and more ape like up in the trees

Perhaps this is akin to what you're looking for? (bear in mind its from 1996 so a lot of things are missing, but it gives the general idea) The one called Australopithecus (just underneath humans in the cladogram) would have been about 4 feet tall and spent time both in the trees and walking upright on the ground and lived 3-4 million years ago. Further down the cladogram (and further back in time) we have Aegyptopithecus, (about 35 million years old) who predated apes and modern monkeys, that was the size of your standard monkey.

lostexpectation wrote:

http://scienceblogs.com/laelaps/2009/07/suminia_life_in_the_trees_260.php

Have to agree with that article. There is an annoying tendancy for 'tabloid science' these days where every potential transitional fossil is heralded as the next big thing (the Ida media frenzy is a prominent example). Suminia was one of many tree dwelling mammal like reptiles living around that time, many of which could be potential ancestors to modern mammals. In fact, a non tree dwelling creature from the same time could have been the direct ancestor of later tree dwellers. It could even be a case that Suminia and it's close relatives were an evolutionary offshoot.

Wibbs

I thought this was a fairly old idea. I remember it being mooted as a theory back in the 70's. Seems sensible.

lostexpectation

thanks i come back and read you answers eventually

r3nu4l

Wibbs wrote: »

I thought this was a fairly old idea. I remember it being mooted as a theory back in the 70's. Seems sensible.

I was the same, I always assumed this was the case...obviously I wasn't listening closely enough in my animal systematics lectures way back when

I can tell you all about the evolution of reptiles to birds and the adaptations of birds to flight but human evolution wasn't covered that closely and I may have been hungover the day that was covered

So, how does this fit in with the theory that humans evolved more than once?

Galvasean

r3nu4l wrote: »

So, how does this fit in with the theory that humans evolved more than once?

Pardon?

r3nu4l

Galvasean wrote: »

Pardon?

Multiregional evolution of humans.

It's an 'alternative hypothesis' but as I say I don't know enough about human evolution to say whether it's bull or not. Richard Leakey couldn't find in favour or against this theory...

Just throwing it out there

Galvasean

r3nu4l wrote: »

Multiregional evolution of humans.

It's an 'alternative hypothesis' but as I say I don't know enough about human evolution to say whether it's bull or not. Richard Leakey couldn't find in favour or against this theory...

Just throwing it out there

Oh that. I'm pretty sure it was discredited along with the neanderthal/modern human hybrid child. Although it's not really my area of expertise. I wouldn't mind hearing Wibbs' views on it.

Wibbs

I would be in favour of a more complex interaction between different humans in the past. The out of africa thing for me has too many holes. It's too pat and a tad too "fashion" driven for me. Genetics is a helluva tool and has told us much, but I think science at the moment is too reliant on it for a source of origins and timescales. Especially given the dearth of fossil remains and viable DNA that can be extracted from same.

Now I do believe humans as a species originated in africa. But I believe that this was in successive waves and later hominids interacted with and reproduced with earlier hominids that they came across in their travels. Specifically Erectus and in the case of Europe Neandertals. I dont favour the pure multiregional hypotheses, where its all about the local. I would think of it broadly as Erectus leaves africa. Moves all over the globe(except the new world). Evolution of hominids continues in Africa, but it also continues in the rest of the world where erectus exists. It seems strange to me that such evolution should be very fast paced in Africa, yet we're to believe that Erectus was pickled in aspic elsewhere even with local adaptation pressures? I don't buy it. Plus as Neandertals in Europe prove erectus did evolve into later forms. Whose to say there's not a similar erectus evolution in asia say. One we've not seen yet. Flores man(another erectus) shows how fluid and local this can be.

Then early not quite sapiens evolves in africa and like an aussie back packer decides to go walkabout. They move into area where erectus and it's descendants live. They get jiggy with it and the populations mix and the earlier gets brought into the later. Other cultural pressures do in the rest of the erectus/neandertals(and some of the moderns too). That makes far more practical sense to me than the current idea, which is erectus stays largely the same for a million years. We come along and completely replace them in those areas with no interaction or gene mix. It just doesn't fit for me.

Even the genetic evidence as outlined in that wiki entry suggests some local continuity of genes, not found in other locales that are significantly older than the 200,000 yr old migration of (nearly) modern humans. That makes no sense if we all stem from that population. We didn't lick those markers off a stone.

Plus in the example I gave on the other thread, http://www.boards.ie/vbulletin/showpost.php?p=61812247&postcount=10 DNA can leave big holes in our understanding of whats going on.

OK I'm of european stock. Lets say I marry an african lassie and we have two sons. One of them marries a japanese woman and the other marries a south american woman from the high andes. If we look at their kids mitichondrian DNA it'll show that they're either Japanese or Andean indian. No trace of African or European. If you look at their Y chromosome DNA they'll look like Europeans. In both cases No trace of African DNA at all, yet they would share the genetic heritage of the oldest people on the planet. That's just over 3 generations, yet we're supposed to believe that over 100's of 1000's generations we're not missing out some huge chunks of what is going on? I dont buy it.

r3nu4l

Ah, right. So if we did evolve from a tree-dwelling ape then what we're saying is that this happened before various Homo species (erctus, sapiens etc) began evolving. The tree-dwelling ape was their ancestor.

This would be opposed to multiple lines of tree-dwelling apes giving rise to distinct local Homo sapiens species

Makes more sense I suppose

Wibbs

Oh yea way before. Erectus was fully adapted for upright walking and running. Analysis(of turkana boy) suggests that erectus was very fast as a runner. Faster than modern humans. Make the Usain Bolt lad look like a pensioner. They were a serious apex predator it seems. Would be amazing to go back in time and see one in action. Magnificent looking buggers.

There are so many unusual things happening at times, even with "us" homo sapiens. Around 40,000 yrs ago a lot of things changed, seemingly overnight. We looked the same in the bones, diet was the same(locally) stone tools didn't change much, but things were afoot. We started to live longer for a start. Much longer. Before that point 30 would be old, 40 would be ancient(though at leats one Neandertal was 40). Then we started to live to 60 for no apparent reason. Art and culture exploded. Again we looked the same in the bones and so far nada has been found in the genes to explain it.

Zillah

Wibbs wrote: »

There are so many unusual things happening at times, even with "us" homo sapiens. Around 40,000 yrs ago a lot of things changed, seemingly overnight. We looked the same in the bones, diet was the same(locally) stone tools didn't change much, but things were afoot. We started to live longer for a start. Much longer. Before that point 30 would be old, 40 would be ancient(though at leats one Neandertal was 40). Then we started to live to 60 for no apparent reason. Art and culture exploded. Again we looked the same in the bones and so far nada has been found in the genes to explain it.

Er, surely it was the explosion of art and culture, which resulted in better and more stable food supplies, organised social structures and safer accommodation?

Diet may not have changed in the content very much, but surely organised farming would result in a quantity change?

Wibbs

40,000 years ago is way before farming though. We're in middle palaeolithic/stone age times here. Oh doubtless there was some environmental change involved, but what was it? It seemed to happen pretty much worldwide very rapidly. There had been art before, but it was sporadic and very small scale(geometric marks in small blocks of red ochre).




As for diet, yes I agree with you farming increases the quantity, but it can be argued decreases the quality for the individual. Early farmers are not as robust as late hunter gatherers and the dietary changes can require adaptations by the body too when novel proteins are brought into the diet(gluten lactose etc).

r3nu4l

Just to update, I have a textbook called 'The Human Past' (got it for free) and read a bit of it last night, it pretty much debunks the multi-regional theory as well...and it's about 15 years old.

Galvasean

r3nu4l wrote: »

Just to update, I have a textbook called 'The Human Past' (got it for free) and read a bit of it last night, it pretty much debunks the multi-regional theory as well...and it's about 15 years old.

Well the recent finds in Georgia seem to throw the door back open for the multiregional theory:
http://www.boards.ie/vbulletin/showthread.php?t=2055677178

Wibbs

Like everything with human evolution I reckon it's never going to be a simple answer. Researchers in Africa are lucky in that they have an amazing array of fossil hominids(even there it's very few) in easily accessible(relatively) outcrops, particularly around the great rift valley. Outside africa the picture is very much more cloudy and the fossil record is very sparse. A handful of bones and fragments. This georgian site is amazing for it's finds because of that. And the notion that erectus may have evolved more outside of africa and then migrated back.

I don't see a problem with that. Neandertal evolved in Europe as far as we know and spread as far as russia and israel.They may have gone even further south during particularly cold glacial times. With their body shape heat would have buggered them up otherwise. Erectus who would have been more suited to temperate and tropical climates may have moved all over the place. They got as far as the far reaches of eastern asia and recent findings suggest they got as far as the island of flores(long enough ago that they adapted a smaller size in response to island living). Amazing achievement considering the size of their brains.

The evidence or lack of it is the problem. Ireland is a good example. Most books will tell you humans only got here after the last glacial period. 8000 years ago?. Yet very early humans were in britain way before that. 600,000 years before that. Homo erectus basically or more evolved versions heading towards neandertals. With our ancestors absence of evidence is always not evidence of absence. The chances are stratospherically high that they were here too for a very long time. Sadly the glaciers scraped so much of the soil away and any evidence with it, so we may never know(southern england got lucky in that the glaciers never fully covered that end so deposits of great antiquity still exist). Then again in the national museum there is a neandertal stone tool, but the label suggests it was brought here by a glacier. Given the glaciers generally ran north to south I don't quite buy that. I'd love to know how they figure a stone tool ended up flowing towards the north from a warmer clime.

Wibbs

What is amazing about modern humans is that we're the odd ones out. If you look at a neandertal you can see features that go all the way back through earlier hominids. Features we don't have. Massive nasal cavities, brow ridges, to name but two and we have features they don't have like high vaulted skulls* flat faces, chins and a few others. Most of our ancestors were far more robust too. I dont care how big a guy you are, or how strong you are, stepping into a cage fight with an erectus and defo a neandertal would not go well for you. "Here bookie, I know the other lad is world MMA champ but my money's on the ginger lad with no chin. Ten seconds down in the first round"

If you had a party and gathered all the major versions of our ancestors, they would be looking at us as the weird ones, more than the other way around. We would be the odd man out as it were. Which is interesting as it suggests a set of evolutionary pressures quite a bit different to our cousins.

Thread for another day maybe.:)



*not just to fit our brains in either as the largest homind brain size wise belonged to a Neandertal.