Evolve

With this spell, a wizard can cause a normal animal to
evolve and change into an intelligent, basically humanoid
lifeform. By using evolve on multiple specimens and exerting
patience, a wizard can potentially create an entire race of servant
creatures.
The creature to be affected must be a normal, nonmagical
animal. Small creatures are usually the target of the spell, but
a normal animal of any size can be used. While mammals are
the best subjects, the spell can be successfully performed on
all sorts of creatures, including such diverse animals as reptiles
and insects. The spell does not work on plants. The animal
receives a normal saving throw based on its Hit Dice to
avoid the effects of the spell; the saving throw is adjusted according
to the creature’s life order, as follows.
Life Order

Adjustment:
Mammal: 0
Bird: 1
Reptile: 2
Amphibian: 3
Fish: 4
Arthropod: 5
Other: 6