quote:
Wow, she must have been some kind of WOMAN — since ONLY her lineage survived among all the supposed competing hominid type groups and sub-groups!
Actually, as PaulK points out, this isn't so surprising. It is to be expected.Consider all the people alive today. Now take a set that consists only of the mothers of this first group. Since a woman can have several children and we are excluding childless women, this second group must be smaller than the first.
Now take all of the mothers of the women in this second group. Again, we are ignoring women who had no children or only sons, and one woman can have several daughters, so this third group is going to be smaller than the second.
Likewise, if we take the set of all mothers of this third group, this fourth group will be smaller still.
So, going backwards like this, we always have a set of females that are small (in numbers) than the previous group.
Eventually, we will get a group that consists of a single female -- the common female ancestor of all of the women in the previous groups, and so of all the humans in the first group.
As PaulK points out, this simply has to happen -- the only question is how far back do we need to go before we reduce the female ancestry to one? Perhaps only a few thousand years, perhaps we need to go all the way back to a mammalian ancestor in the Cretaceous.
As it turns out, an examination of the mitochondrial DNA (which is usually only inhereted from the mother) suggests that this "mitochindrial Eve" lived about 60,000 years ago.