Evolution works as a fork in the road. Some change, some don't. But as time passes, both keep right on evolving. We do not come from any modern apes, but we are both primates. There was one common primate that existed in the past that is our great great great (thousands or even millions of greats) great grandparents for all primate species. You don't look exactly like your siblings. In 1,000 years, assuming your seed is kept alive that long, your great great great.....grandchildren will all look different. If you are white, and your white brother marries a latino woman, your nieces and nephews wont look the same as your children. They could marry an Eskimo and a Russian and the differences of the next offspring grows larger. If the black sheep of the family marries a black sheep from another family (dumb, unsuccessful, etc.) that line might turn out fairly dumb, whereas the success from your family might marry a successful person and that line turns out very successful. Play it out over 100,000 years and you might even become responsible for 2 different species, one dumb and one smart. More realistically, the dumb line might not continue the line and die off without offspring eventually. The original dumb one didn't survive the 100,000 years.
Hopefully that makes sense. I'm using regular langauge as opposed to scientific language. Read up about Mendel's flowers if you'd like a brief introduction to genetic heritage.