Two Parts/Paragraphs:
Read the following article:Late Pleistocene human population bottlenecks,volcanic
winter,and differentiation of modern humans by Stanley Ambrose
http://www.bradshawfoundation.com/stanley_ambrose.php
Part1:
What is an evolutionary bottle neck and what are the consequences?
Part2:
What caused the bottleneck 70,000 years ago? What were the consequences to
early humans?