Speciation is the process which
different species emerge a
common ancestor species.
generally begins when populations
the same species become
isolated, i.e., when they
separated by some physical
that disallows crossing between
from one population and
of another population.

Groups for a long time kept
under geographical isolation to
accumulate different phenotypical
from each other by
of genetic variability (mutations
recombination) and natural
selection. those differences reach
a that makes the crossing
individuals of one group individuals
of the other impossible or the
generation fertile offspring nolonger
happens is said that speciation
occurred.