Because it's only when you do that, that you can talk about --  -- it's only when you do that, [that] you can talk about how we looked like and how we behaved at different times, and how those likes and looks and behaviors changed through time.
これでようやく お話できる  これでようやく別々の時間に 我々の祖先の容姿と行動について また時間を経てそれらがどう変化したか 語ることができるのです