The focus was on Primates and the antics of our closest relatives made for rewarding viewing. Clever old Attenborough built the series to a wonderful ending - a simple act of generosity from one chimp to another in the lending of a tool for cracking open a nut. Everything was kept beautifully low-key, with the overwhelming implications of what we might understand by the idea of the higher nature of some animals being left to itself. A nice contrast was created with the first sequence of the episode, in which we saw the sometimes ruthless discipline employed within groups of hamadryads, and conflict between their 'tribes'. (Fabulous visuals there, by the way - but then you can apply that comment to any sequence at all in the series.)
I suspect the final episode was all a touch more teleological in its implications than the makers may have bargained for, but I also suspect that's something written into the nature of things that we can't get away from.