You have actually covered two topics. As a general group dogs would cover all species of domestic dogs for example Poodles, Great Danes, etc. As for bears it covers all species such as black bears, brown bears etc. You are correct in pointing out that Grizzlies and Kodiak bears are sub species of Brown bears and as you asked, yes the sub species developed due to specific environmental locations and conditions.

Bear taxonomy has been screwed up for centuries. During the early 20th century, almost every specimen brought in was described as a new subspecies or even a new species. Now, the pendulum has swung in the opposite direction and everything is considered to be a single species, on the basis of a few natural hybrids. I suspect that the truth is somewhere in between.

The brown bear (Ursus arctos) includes all brown bears plus grizzlies and Kodiaks.

I was playing deer hunter, and they had kodiak, grizzly and brown bears. I know kodiak and grizzlies are different, but they are both types of brown bear. There are like 16 sub species of brown bear, throughout north america and europe. So what i couldn't understand is; so is brown bear kinda like a dog, and the kodiak and grizzly and others like breeds of brown bear. or is there a brown bear that evolved here and there depending upon where it lived to get the sub species