Test

[Jacques Cinq-Mars]

Test

[shenzhou]

This paper has an interesting perspective on human brain evolution.

Neocortex evolution in primates: the ‘social brain’ is for females

Patrik Lindenfors. Biology Letters. DOI:10.1098/rsbl.2005.0362

Abstract:

According to the social intelligence hypothesis, relative neocortex size should be directly related to the degree of social complexity. This hypothesis has found support in a number of comparative studies of group size. The relationship between neocortex and sociality is thought to exist either because relative neocortex size limits group size or because a larger group size selects for a larger neocortex. However, research on primate social evolution has indicated that male and female group sizes evolve in relation to different demands. While females mostly group according to conditions set by the environment, males instead simply go where the females are. Thus, any hypothesis relating to primate social evolution has to analyse its relationship with male and female group sizes separately. Since sex-specific neocortex sizes in primates are unavailable in sufficient quantity, I here instead present results from phylogenetic comparative analyses of unsexed relative neocortex sizes and female and male group sizes. These analyses show that while relative neocortex size is positively correlated with female group size, it is negatively, or not at all correlated with male group size. This indicates that the social intelligence hypothesis only applies to female sociality.

The paper can be downloaded here: http://www.zoologi.su.se/research/Lindenfors/Publications/05BL.pdf

[SNARK]

Hey!

Thank you for letting me join your forum. I am a sculptor and have recently been engaged to produce eight life-size hominid figures for a museum in Spain. My hope and interest in your group is to understand the proportions and morphology of these ancestors in a way that allows me to more accurately reflect the fossil record. To that end, I have questions about skeletal reconstructions and joint-to-joint measurements and information or access to any schematic drawings that illustrate said skeletons from frontal and profile views. The hominids I am intersted in are: Oreopithecus, Dryopithecus and Australopithecus (Africanus and Afarensis).

Where do I start?

Thanks!

Tim Lawrence
Sculptor

[Askur]

Wouldn't it be more correct to call the modern man Homo sapiens domesticus rather than Homo sapiens sapiens?
When we take a look at human populations that have lived as hunters and gatherers until recently, like the aboriginals, they have a much thicker skull and bigger jaws and teeth than most other people.

When humans domesticates animals, the same pattern is always repeated; an increase in under- and overbites, smaller body size (at least in the start), expanded breeding season (or breeding year round), shorter jaws, smaller teeth, monomorphism (males and females looks more alike), neotony, juvenile behavior, skull changes, reduced brain size and other stuff. When humans selected the kind of animals they wanted, they were picked for their meat, milk and fur and so on. Never for reduced brain size, curled tail, reduced jaws or any other well known traits, even if modern breeding of today are often extreme and selecting animals because of the way they look, that was a luxury out ancestors could not afford. These are traits that just followed. Not just once or twice, but as far as I know, always, no matter what species of mammal who were selected. So it is clearly not a coincidence.

Each time humans have become farmers and starts to live in permanent settlements and change their way of life from something "primtivie" to more modern, we see exactly the same changes in us after some generations.

In the last thousands years most people over the world have evolved shorter jaws (which often gives too little room for all the teeth, even if also they have been reduced in size), a reduced sense of smell, even new blood types and bio chemistry, an increase in under- and overbites, monomorphism (reduced secondary sexual characteristics, neoteny in other words), reduced brain size (if I remember correct, it has become reduced with as much a 10% since humans started to grow their own food), thinner skull and weaker muscles, most likely more juvenile behavior and other traits.

Just the same pattern as in domesticated animals. It seems that after humans started to live in early permanent villages and towns, where they domesticated animals and were growing their own food, they became self-domesticated.

In crowded environments and a new way of living, there is always someone that will do it better than others, and there is always someone that will produce more offspring than others. Even today we will probably see some pattern on who is having most children in the biggest cities in the world, and who is producing few or none. Of course, the bigger the cities are, the slower the evolution goes with all those poeple there are not bottle-necks which can speed it up. The original natural selection may be gone, but there is still other forms of selections going on, even if it may not be constant over time and goes very slowly.

Some says those humans living today have almost identical DNA with the humans that lived in caves and made paintings on the cave walls. Maybe, but this is also the case with domesticated animals and their wild cousins, and still we see some very big differences. It is said if we took a new born baby from its parents hundred thousands years ago and brought it to our modern time, no one would be able to tell the difference when he or she grew up. This is probably true, but I suspect it would be a very big chance the child would not like to go to school and sit on a chair most of the day and listen to teachers. There is a big chance the child would become one of these problem childs, not being quite comfortable with the modern way of living and all its noise, rules and laws and so on. That's just my opinion, but thats what I think.

It seems like Homo sapiens sapiens is almost extinct, and is being replaced by Homo sapiens domesticus. Is there any other way to explain the changes in us that have showed up since we stopped living as hunters and gatherers?

[Askur]

Wouldn't it be more correct to call the modern man Homo sapiens domesticus rather than Homo sapiens sapiens?
When we take a look at human populations that have lived as hunters and gatherers until recently, like the aboriginals, they have a much thicker skull and bigger jaws and teeth than most other people.

When humans domesticates animals, the same pattern is always repeated; an increase in under- and overbites, smaller body size (at least in the start), expanded breeding season (or breeding year round), shorter jaws, smaller teeth, monomorphism (males and females looks more alike), neotony, juvenile behavior, skull changes, reduced brain size and other stuff. When humans selected the kind of animals they wanted, they were picked for their meat, milk and fur and so on. Never for reduced brain size, curled tail, reduced jaws or any other well known traits, even if modern breeding of today are often extreme and selecting animals because of the way they look, that was a luxury out ancestors could not afford. These are traits that just followed. Not just once or twice, but as far as I know, always, no matter what species of mammal who were selected. So it is clearly not a coincidence.

Each time humans have become farmers and starts to live in permanent settlements and change their way of life from something "primtivie" to more modern, we see exactly the same changes in us after some generations.

In the last thousands years most people over the world have evolved shorter jaws (which often gives too little room for all the teeth, even if also they have been reduced in size), a reduced sense of smell, even new blood types and bio chemistry, an increase in under- and overbites, monomorphism (reduced secondary sexual characteristics, neoteny in other words), reduced brain size (if I remember correct, it has become reduced with as much a 10% since humans started to grow their own food), thinner skull and weaker muscles, most likely more juvenile behavior and other traits.

Just the same pattern as in domesticated animals. It seems that after humans started to live in early permanent villages and towns, where they domesticated animals and were growing their own food, they became self-domesticated.

In crowded environments and a new way of living, there is always someone that will do it better than others, and there is always someone that will produce more offspring than others. Even today we will probably see some pattern on who is having most children in the biggest cities in the world, and who is producing few or none. Of course, the bigger the cities are, the slower the evolution goes with all those poeple there are not bottle-necks which can speed it up. The original natural selection may be gone, but there is still other forms of selections going on, even if it may not be constant over time and goes very slowly.

Some says those humans living today have almost identical DNA with the humans that lived in caves and made paintings on the cave walls. Maybe, but this is also the case with domesticated animals and their wild cousins, and still we see some very big differences. It is said if we took a new born baby from its parents hundred thousands years ago and brought it to our modern time, no one would be able to tell the difference when he or she grew up. This is probably true, but I suspect it would be a very big chance the child would not like to go to school and sit on a chair most of the day and listen to teachers. There is a big chance the child would become one of these problem childs, not being quite comfortable with the modern way of living and all its noise, rules and laws and so on. That's just my opinion, but thats what I think.

It seems like Homo sapiens sapiens is almost extinct, and is being replaced by Homo sapiens domesticus. Is there any other way to explain the changes in us that have showed up since we stopped living as hunters and gatherers?

[Askur]

Wouldn't it be more correct to call the modern man Homo sapiens domesticus rather than Homo sapiens sapiens?
When we take a look at human populations that have lived as hunters and gatherers until recently, like the aboriginals, they have a much thicker skull and bigger jaws and teeth than most other people.

When humans domesticates animals, the same pattern is always repeated; an increase in under- and overbites, smaller body size (at least in the start), expanded breeding season (or breeding year round), shorter jaws, smaller teeth, monomorphism (males and females looks more alike), neotony, juvenile behavior, skull changes, reduced brain size and other stuff. When humans selected the kind of animals they wanted, they were picked for their meat, milk and fur and so on. Never for reduced brain size, curled tail, reduced jaws or any other well known traits, even if modern breeding of today are often extreme and selecting animals because of the way they look, that was a luxury out ancestors could not afford. These are traits that just followed. Not just once or twice, but as far as I know, always, no matter what species of mammal who were selected. So it is clearly not a coincidence.

Each time humans have become farmers and starts to live in permanent settlements and change their way of life from something "primtivie" to more modern, we see exactly the same changes in us after some generations.

In the last thousands years most people over the world have evolved shorter jaws (which often gives too little room for all the teeth, even if also they have been reduced in size), a reduced sense of smell, even new blood types and bio chemistry, an increase in under- and overbites, monomorphism (reduced secondary sexual characteristics, neoteny in other words), reduced brain size (if I remember correct, it has become reduced with as much a 10% since humans started to grow their own food), thinner skull and weaker muscles, most likely more juvenile behavior and other traits.

Just the same pattern as in domesticated animals. It seems that after humans started to live in early permanent villages and towns, where they domesticated animals and were growing their own food, they became self-domesticated.

In crowded environments and a new way of living, there is always someone that will do it better than others, and there is always someone that will produce more offspring than others. Even today we will probably see some pattern on who is having most children in the biggest cities in the world, and who is producing few or none. Of course, the bigger the cities are, the slower the evolution goes with all those poeple there are not bottle-necks which can speed it up. The original natural selection may be gone, but there is still other forms of selections going on, even if it may not be constant over time and goes very slowly.

Some says those humans living today have almost identical DNA with the humans that lived in caves and made paintings on the cave walls. Maybe, but this is also the case with domesticated animals and their wild cousins, and still we see some very big differences. It is said if we took a new born baby from its parents hundred thousands years ago and brought it to our modern time, no one would be able to tell the difference when he or she grew up. This is probably true, but I suspect it would be a very big chance the child would not like to go to school and sit on a chair most of the day and listen to teachers. There is a big chance the child would become one of these problem childs, not being quite comfortable with the modern way of living and all its noise, rules and laws and so on. That's just my opinion, but thats what I think.

It seems like Homo sapiens sapiens is almost extinct, and is being replaced by Homo sapiens domesticus. Is there any other way to explain the changes in us that have showed up since we stopped living as hunters and gatherers?