"What do you mean by "more evolved"? What metric(s) is/are measured to determine the level at which an individual is "evolved"?"
Pick some metrics. It doesn't matter. If evoloution is real, the devil is in the details. If the theory holds, plants and animals should have evolved to suit their particular environments. Changing the environment of one group should put them at the disadvantage when placed in a different environment.
I probably should have been PC and said "evolved differently" but that's not what Darwin alluded to, even though I think that applies as well.
My point is, that it can't be ruled out as a possiblity, or even a probablity when scientifically addressing the theory of evoloution as it relates to man.
On a side note, it's interesting how plants are rarely, if ever, discussed when the subject of evoloution pops up. I'm still wondering how that sharp thorn came to be. ;)