domenica 19 aprile 2015

Il Clima e l' Uomo.

Esiste una correlazione diretta tra la geografia e l'Uomo, si sa. E questa correlazione - che vale per tutte le creature viventi - è mediata dal Clima, una variabile che ha sempre influenzato gli spostamenti, la quantità e la qualità di vita di tutti i viventi.

Earliest humans migrated to Europe 

1.4 million years ago 

thanks to rising temperatures 

 A warming climate may have enabled the earliest humans to venture into Western Europe 1.4 million years ago, a new study suggests. 

The Acheulean tool technology period - between 700,000 an 300,000 years ago - followed  the more primitive Oldowan period. 

Tools at the time included large stone hand-axes  made from flint and quartzite, used to scavenge from carcasses  
[Credit: Nico Tondini/Robert Harding World Imagery/Corbis]

 Researchers believe that the spread of our distant human ancestors, the hominins, had been halted by colder and drier temperatures. 
But as conditions warmed, they were able to branch out from Africa into Spain, and ultimately spread across Europe. The research was led by Dr Jordi Agusti from the Catalan Institution for Research and Advanced Studies (ICREA). 

Published in the Journal of Human Evolution, the paper suggests climate change affected the amount of resources available.

The theory is based on analysis of the Barranco León site in the Guadix-Baza Basin in southeast Spain. 
Here, simple Oldowan tools have previously been found, linked to the earliest known hominins 1.4 million years ago.
 But they were not able to migrate to this region until conditions improved.

 The researchers said that the early Pleistocene era (the era lasted from 2.59 million to 11,700 years ago) was characterised by colder and drier weather. 
This ‘possibly impeded the settlement of this region by the early hominin population from the southern Caucasus,’ the researchers wrote. 

But shortly afterwards, ‘when the climatic conditions were again favourable, a hominin presence is suddenly evidenced.’ 
It should be noted that the warming climate referred to here is on a vastly longer time scale than modern climate change. 
At the time 1.4 million years ago, though, temperatures warmed above 13°C (55°F) and humidity increased, allowing hominins to inhabit the region - scavenging carcasses in the region with the help of tools. 
‘The data reported here clearly support the idea that the early hominin occupation of Europe was strongly constrained by climatic and environmental conditions, rather than by physiography or cultural factors,’ the researchers wrote. 

Author: Jonathan O'Callaghan | Source: Daily Mail Online [April 14, 2015]