>>11154190That's what we call speciation. I recommend reading Evolution by Futyama, 4ed, Chapter 9: Species and Speciation.
Essentially there are three kinds, allopatric, sympatric, and peripatric.
Allopatric speciation is probably the most common, in which a physical barrier occurs between two populations, eventually subjecting them under different conditions and thus evolving different traits.
Peripatric occurs when a peripheral poblation becomes isolated.
Then parapatric and sympatric speciation are rare forms and involve no physical barrier between populations. The mechanisms in which occur are varied, some controversial, and most applicable to only to plants.
Pic related: parapatric speciation. There is no physical barrier, but there are conditions in which plants evolve different traits.
