DNA suggests that Beaker people did replace Neolithics in Britain

[Duncan Head]

http://www.bbc.co.uk/news/science-environment-43115485

https://www.theguardian.com/science/2018/feb/21/arrival-of-beaker-folk-changed-britain-forever-ancient-dna-study-shows

[Andreas Johansson]

Interesting, thanks

[Imperial Dave]

disease is a possibility although one wonders how such a widespread 'overunning' of the gene pool could take place so completely

[Erpingham]

Disease is an obvious factor.  A disease which was endemic among the newcomers but spread slowly because of their dispersed culture could go like wildfire through a population used to assembling people together in masses to celebrate events. 

A weakened population could more easily be displaced from the prime agricultural land and set on a declining path.

But, without more evidence to fine tune the diffusion/migration model, be difficult to say anything hard and fast.

[RichT]

From what we know of more recent examples (such as the replacement of the population of the Americas by Europeans and others) it's a combination of many causes - disease, violence, displacement and competition all have a part to play. Climate changes would exacerbate the effects of displacement particularly (by taking the most productive land).

[Anton]

Very interesting.

One of the reasons disease was so devastating in the New World was its populations isolation from the immunity developed to trans species diseases by the incomers.  Neolithic Britain was not isolated, in fact the sea ways were busy and the advance of the Beaker folk relatively slow. Also the original population seem to have been mixed stock farmers not too different from the Beaker Folk.  Given that I'd expect trans species disease immunity to have already developed.  Disease could have played a role but it would not be my first choice as the decisive agent of population change.

I hope we find out more.

[aligern]

I'm a great believer in the effect of disruption on native populations. Hunter gatherers have lives that run to a rythm , in winter we go to the caves , fish by the river and eat the meat we smoked in the summer...in summer we folliw the aurochs to their summer pastures and kill a few. When someone new arrives they disrupt the pattern of life and likely  the pattern of breeding.  A transhumance lifestyle only needs interrupting for a few seasons  to cause a steep real population decline. The Beakers might only advance slowly, but if they disrupt the hunters each time they will gradually destroy them.
Roy

[Erpingham]

But the Beakers (a whole tribe of ginger-haired figures in lab coats?) are displacing farmers.  Technologically, they aren't much in advance of the natives.  They are also not warriors falling on the peace-loving hippies of Stonehenge - Neolithic violence is well attested.  So, we must look for things that might explain why the natives were swept aside with limited interbreeding.  Disease is one possibility.  Failure of the natives to adapt to climate change, with the Beakers being better adapted?  Implossion of native society due to external and internal stresses previously mentioned leading to Beakers opportunistically occupying a semi-deserted landscape and able to overcome the remnants of native society?

[Imperial Dave]

Easter Island scenario? Unlikely but....?

[Erpingham]

Easter Island scenario? Unlikely but....?

Wasn't that based on failure to sustainably exploit resources?  The natives in Britain had plenty of space to expand into, unless they were self-limiting in what type of land they could utilise and used it all up.  Given that they settled the whole of the British Isles it seems unlikely.

Another possible factor would be a murrain or animal epidemic which the newcomers animals carried but were resistant to.  If they were heavily pastoral, it would be pretty catastrophic.  The plausibility of this  being an agricultural question, we should summon Jim.

[aligern]

The latest thinking I have heard about Easter Island is that the population adaoted to the changes they caused quite well and that collapse did not occur until after the first contact with Europeans and the diseases they brought. Even quite mild diseases in a European context could be deadly to thise who had lived in isolation.

It would be remarkable for there nor  to be intermarriage, so even if disease had carried off three quarters of the natives one would expect mixing. Also if the beakers move onward slowly the population further West would bounce back.
One thing that does keep populations exclusive is religion. Perhaps the two populations were so inimical to one another that mixing was a form of pollution?
Roy

[Erpingham]

It would be remarkable for there nor  to be intermarriage, so even if disease had carried off three quarters of the natives one would expect mixing.

I think the study suggested 10% pre-Beaker DNA (though its not a big sample).  So some intermarriage can be allowed for, or other integration.

One thing that does keep populations exclusive is religion. Perhaps the two populations were so inimical to one another that mixing was a form of pollution?
Roy

Well, their different funerary practices would suggest religious differences but how deep or exclusive these were we'd be guessing.

[Jim Webster]

Easter Island scenario? Unlikely but....?

Wasn't that based on failure to sustainably exploit resources?  The natives in Britain had plenty of space to expand into, unless they were self-limiting in what type of land they could utilise and used it all up.  Given that they settled the whole of the British Isles it seems unlikely.

Another possible factor would be a murrain or animal epidemic which the newcomers animals carried but were resistant to.  If they were heavily pastoral, it would be pretty catastrophic.  The plausibility of this  being an agricultural question, we should summon Jim.

it is possible, but the equivalent of smallpox hitting a a naive human population is at least as possible

[Imperial Dave]

initial contact with new Beaker folk, disease outbreak followed by westward migration/segregation and follow up of occupation of vacated lands

[Jim Webster]

initial contact with new Beaker folk, disease outbreak followed by westward migration/segregation and follow up of occupation of vacated lands

According to the celebrated authority wiki, the population of Mexico fell from 25-30 million to 3 million in fifty years.