Sources refer to the Ramchal’s Derech Hashem.
It should be obvious that if something exists, either in Heaven or on Earth, it must be because God deemed that thing necessary and useful in fulfilling His plan for the universe. The laws of physics were designed so that everything in the universe could serve its purpose. [II, 1.1]
As discussed above (part I, part 5), everything in the universe is maintained by spiritual forces. This is true of everything in the physical realm, no matter how imposing or how insignificant it might seem.
God oversees all these forces and their influences, as well as the angels appointed to keep things running. [II, 1.2]
Humanity differs from other species in that we possess free will to interact with forces that lead to perfection or defects. Unlike other creatures, man is not merely acted upon by the universe; we possess the capacity to influence creation. Because of this the degree of providence shown by God to mankind must necessarily be different from that which He extends to other species.
When it comes to man, God’s providence must scrutinize our deeds, something that is not necessary with animals. Similarly, God’s providence must bring humanity results consistent with their actions. Again, this is not called for with other species.
God’s other creatures do not exert influence on the universe; they are merely acted upon. Therefore, it is sufficient that God maintain the species in general; the fate of any individual member is inconsequential. In the case of man, however, individual members exert influence and affect creation. Therefore, individual providence (hashgacha pratis) is called for. [II, 1.3]