I have never bought the idea, which is just about universally accepted by the scientists, that we Germans, and Danish, Irish and Welsh evolved from Negroes who walked north out of Africa 50,000 years ago.
No, I cannot believe that we evolved from African negros.
That's not the idea. We didn't evolve FROM Negroes. The facts are that the Negroes and all other current peoples have evolved from modern humans who lived in Africa at least 160,000 (possibly 300,000) years ago. A small group left Africa 70,000 years ago. All other peoples--Europeans, Asians, even Australian aborigines--are descended from this group and are more closely related to each other than any of them are to Negroes.
So why the differences? A lot of evolution can happen in 70,000 years. Mutations create traits which, if helpful for survival, will spread through the population over many generations. Skin color is one of these. Dark skin is definitely helpful in the tropics and light skin is helpful at high latitudes. Therefore Europeans with lighter skin will survive longer and have more babies. The whole population will eventually get light. We had dark skin until about 7,000 years ago.
A couple of other points.
There are a lot of other differences between races than skin color. Bone density and structure, protruding lower faces, receding craniums, and (in my opinion) a proclivity for emotion and violence plus low IQ are all genetic characteristics of Negroes. (But it's "raciss" to say so.)
Humans are NOT descended from Chi mps. Humans and Chi mps are descended from an ancestral ape and the separation occurred about 6,000,000 or 7,000,000 years ago.
Incidentally, Humans and Chi mps are much more closely related to each other than Chi mps are to Gorillas.
Look up the dictionary definition of "subspecies" and tell me why Negroes are not a separate subspecies.
There were other "out of Africa" migrations before 70,000 years ago, going back to about 1,500,000 years ago by Homo erectus and others that were not the same species as us.