one common statement in popular science when speaking about evolution
is that we all derive from a common ancestor, the "original eve".
while a posteriori, it is true that mitochodrondrial DNA allows to
trace back common ancestors in our heredity, it is certainly
overstated. When thinking evolution, our focus is to look back from
the present to our origins, but a the time of these "few" original
eves, many different eves coexisted and acted -as parts of the
whole population- in the evolution.
Evolution is more like a Banyan tree than a graph written on a board
where species evolve from primitive forms into more and more complex
forms, including an idealistic vision of our position on this tree.