While all are dogs, a Chiwawa, a Labador Retriever and a Pit Bull all look different, sound different when they bark, and if you slap each one upside the head each will fuck you up in their own particular way.
Not so much the Lab but the Chiwawa would be pissed.
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Each strain evolved differently according to it's environment around the world - Sativas in the tropics with long flowering periods because of the warm year round temperature, Indicas where it's colder with a shorter growing season requires a shorter flowering period for the strain to survive. Strains at high altitudes near the equator get lots of UVB, affects the trichs differently and they'd evolve to produce a different mix of cannaboids than a strain that evolved along the north western coast of North America, where it's wet with a shorter growing season.
As for phenos, think of children in a family - two girls have the same two parents but don't look exactly alike, one might be athletic and smart while the other is clumsy and stupid (bet you thought I'd say athletic and short). When they grew up if both had children with the same man the athletic daughter may have more chance have athletic children than the clumsy women becuase of passed genes.
So if you want to have athletic children you may have a better chance with the athletic girl = breeding phenos within a strain for the traits that you want your new strain to have. A good example of this is Bubblegum - it was brought to Europe where Serious developed the sativa pheno and TH developed the indica, both through inbreeding.
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