If Environments Differed, Why Didn't Man Evolve into Separate Forms?

   Man came out of Africa, it is said, and migrated to the other climes of earth. Some were hot, some were cold. Some would have placed him fishing in oceans, and other had him chasing the hills for his meat. Not every environment was the same.
   So, why is man all the same? Why did only one form evolve?
   He might have swung from trees in one environ while not a tree was to be had in another, but rather there was nothing but parched land to walk on. He faced even different foes of nature,  for even the beasts he fought against probably varied from clime to clime. And even the diseases and pestilences he encountered probably differed.
    So, why did just one form of a man evolve? The clothes he threw on his back varied. It is they that were dictated by the environment, not the form of the man, himself. Maybe he hunched over a little more back in those early years and maybe he was shorter, but the form has remained basically the same, and that despite the different climates that should have pressured different looks
   Doesn't adaptation to the environment suggest that different types of humans would have evolved? And, in migration, many of these humans became so far removed from each other that there would not have been much cross-breeding going on between them, that they should remain the same.
   Yes, different races developed, but can we look at those different races and see the influence of environment in their differences? Skin pigmentation is perhaps the chief thing. If it is a result of environment, why didn't the environment affect us in other ways, in our form? None of us have a different form, such as being web-footed or fur-covered.
   Differences? I am told some in high climates have wider nostrils and broader chests, to accommodate breathing the thin air. And, some of those in colder climates developed shorter limbs, so the blood would not have to go as far when circulating. I have not double-checked those thoughts, but would guess they are correct. If so, they temper the point I am making, a little.
   At this point, noting men from different climes share the same form, and noting that image appears to be the same as when homo sapiens were first to have come about, I think of a scripture. "So God created man in his own image, in the image of God created he him." (Genesis 1:27)
   Is it significant that only one image, one form, of the human evolved? for if all men were to be in the image of God, indeed, only one image would evolve.
   I wonder if in this matter, as to why man did not evolve into different forms, if religion does not hold a better answer than what evolution does.
    (Post edited and parts rewritten Feb. 8, 2015)