I found articles regarding the "Eve" you asked about in earlier posts. It is a part of the Out of Africa theory and part of molecular evolution. Here are the sites:
http://en.wikipedia.org/wiki/Mitochondrial_Eve
http://www.talkorigins.org/faqs/homs/mitoeve.html
http://www.chartsgraphsdiagrams.com/evolut...ndrial-eve.html
Here is a wiki quote:
"Mitochondrial Eve (mt-mrca) is the name given by researchers to the woman who is the matrilineal most recent common ancestor (MRCA) for all living humans; the mitochondrial DNA (mtDNA) in all living humans is derived from hers. Mitochondrial Eve is the female counterpart of the Y-chromosomal Adam, the patrilineal most recent common ancestor.
The holder of this title is believed by some to have lived about 140,000 years ago in what is now Ethiopia, Kenya or Tanzania. The time she lived is calculated based on the molecular clock technique of correlating elapsed time with observed genetic drift.
Mitochondrial Eve is the most recent common ancestor of all human via the mitochondrial DNA pathway, not the unqualified MRCA of all humanity. All living humans can trace their ancestry back to the MRCA via at least one of their parents, but Mitochondrial Eve can only be reached via the maternal line. Therefore, she necessarily lived much longer ago than the MRCA of all humanity.
The existence of Mitochondrial Eve and Y-chromosomal Adam does not imply the existence of population bottleneck or first couple. They co-existed with a large human population. Some of these contemporaries have no living descendants today, and others are ancestors of all people alive today. No contemporary of Mitochondrial Eve is an ancestor of only a subset of people alive today, because she lived much longer ago than the identical ancestors point......."