Yes. As the divine wisdom is the cause of the distinction of things for the sake of the perfection of the universe, so it is the cause of inequality because the universe would not be perfect if only one grade of goodness were found in things.
As the wisdom of God is the cause of the distinction of things, so the same wisdom is the cause of their inequality. This may be explained as follows.
A twofold distinction is found in things; one is a formal distinction as regards things differing specifically; the other is a material distinction as regards things differing numerically only. And as the matter is on account of the form, material distinction exists for the sake of the formal distinction.
Hence we see that in incorruptible things there is only one individual of each species, forasmuch as the species is sufficiently preserved in the one; whereas in things generated and corruptible there are many individuals of one species for the preservation of the species.
Whence it appears that formal distinction is of greater consequence than material. Now, formal distinction always requires inequality, because as the Philosopher says (Metaph. viii, 10), the forms of things are like numbers in which species vary by addition or subtraction of unity.
Hence in natural things species seem to be arranged in degrees; as the mixed things are more perfect than the elements, and plants than minerals, and animals than plants, and men than other animals; and in each of these one species is more perfect than others.