Actually we are all spirit souls and are intended to associate with God in the spiritual sky where there are innumerable spiritual planets and innumerable spiritual living entities. However, those who are not fit to live in that spiritual world are sent to this material world. This very idea is expressed by Milton in Paradise Lost. Although spirit soul, we have voluntarily accepted this material body and by accepting it have also accepted the threefold miseries of material nature. Exactly when we accepted it and how we accepted it cannot be traced out. No one can trace out the history of when the conditioned soul first began accepting these material bodies.

At present Darwin's theory of the evolution of organic matter is very prominent in institutions of higher learning, but there is information given in the Padma Purana and other authoritative scriptures of the living entities' spiritual evolution from one bodily form to another. This Purana informs us that species amongst plants and vegetables alone. At present everyone is giving stress to Darwin's theory, but in Vedic literature there is immense information about the different species. Darwin expresses the opinion that the species are evolving from lower forms of life, but this is not the whole truth. The soul may progress from lower forms to higher forms, but in the beginning of creation all species were created by Sri Krishna, as indicated in Bhagavad-gita:

sarva-bhutani kaunteya
prakrtim yan ti mamikam
kalpa-ksaye punas tani
kalpadau visrjamy aham

prakrtim svam avastabhya
visrjami punah punah
bhuta-gramam imam krtsnam
avasam prakrter vasat