Idea for a Sci-Fi story

We kind of know how humans evolved, now the question in my mind is why only humans evolved, why not lions, or donkeys. Does evolution call it quits on an animal after certain time, in th sense the lion has remained a lion since monkeys became man, why idnt they evolve into something different, why isnt that flux seen in them.

Anyhow back to the story, the story will have man as he is now, and somebody will start to notice tht some other animal say ants or bees or eagles have started evolving into an intelligent species, theya re forming societies, countries, religion, worshiping, building houses, gathering food etc, and mans reaction to that. This would be an interesting theory, mans reaction to another intelligent species not from some other planet but in his abckyard, someone who might challenge his hegemony on the planet. will there be war once they start developing weapons, what if they start developing on an entirely different plane, they have nuclear weapons when we had bows and arrows.........

thought this sounds like science fiction, Its my kind of science fiction, or should I call it bio fiction haha, well it tackes human sociology in the wake of a changing environment, a drastically changing environment. The story should deal less with the actual evolution and more with the effect on man, socially, philosophically, intellectually... woudl he try to interfere, or just study, when th realization dawns on him that its a competing civilization what will he do, the individual and the crowd......

anyhow I would still like to pursue this interesting point as to why species stop evolving as if they have reached a plateau of achievement. According to evolution nobody should stop evolving, as species near extinction they should find other ways to survive, start thinking, start building and storing food etc.... what is some species is and we dont know hmmmm