True religion consists in knowing God, in knowing our relationship with Him, our duties towards Him, and ultimately, our destiny after leaving the material body in which we reside. People who wish to regain their sight and see life in its true light must turn to Krishna, the Supreme Personality of Godhead, and attach themselves only to His word and teaching, which represent true pure light, true celestial sustenance; thus, they will see the purpose of existence realized for them.
Lord Krishna sometimes appears personally, or He is represented by a qualified being whom He Himself endows with special powers, but in either case, the goal is the same: to bring suffering beings back to Him, to their original abode. The happiness that conditioned souls yearn for is not found anywhere among the countless material planets and galaxies.
This eternal happiness for which they thirst can be obtained only in the kingdom of God. But forgetful beings, held in thrall by the attributes of material nature, know nothing of this kingdom. Therefore, the Lord comes to spread knowledge of the spiritual world, which He accomplishes sometimes in person, in the form of an Avatar, and other times through His qualified representative, also called the son of God. These Avatars and sons of God do not limit their message of returning to God to human society alone; their activity also extends to all other categories of beings, from virtuous saints and celestial beings to beings lower than humankind.
The ultimate goal of existence is to seek to know Krishna, God, the Supreme Personality, as He truly is.
The ultimate goal of existence is also to return to Krishna, to His infinite, absolute, and eternal kingdom, in order to regain the position of eternal servant that we had with Him at the beginning of all things.
What is the evolutionary cycle of species?
Evolutionary cycle of species, or the soul's journey through species.
Lord Krishna teaches us about the hierarchy of beings and the different species.
Among the creations produced by the two manifested energies [spirit and inert matter], those possessing life force [vegetables, grass, trees, and plants in general] dominate over inert matter, stone, earth, etc.
In turn, reptiles, worms, and snakes, which are capable of movement, surpass immobile plants, and animals with developed intelligence are superior to even reptiles.
Human beings are superior to animals, and ghosts to human beings, because they do not have physical bodies.
Above the ghosts are the Gandharvas (celestial singers) and, even higher, the Siddhas (perfect beings), then the Kinnaras (superhuman beings with supernatural powers), and finally the asuras (unenlightened, evil beings, who can subdue the aforementioned beings).