It is only our arrogance that makes us believe we are at the Top of the Food Chain.
If the study of ecology has taught us anything, it is that there are relationships of types of energetic exchanges (gravitational, electromagnetic, chemical, etc) between types of relatively independent entities (molecules, life forms, planets, solar systems, galaxies, etc) that sustain each other's dynamic equilibria. In a nutshell, everything is a type of "food" for something else.
What are Humans food for?
According to Gurdjieff, human death, or certain types of human work, produces a sacred substance called "Askokin" that can be consumed by higher intelligences (demiurges, angels, devas, spirits, etc) that are responsible for maintaining the universal order.
If all life is farmed by higher powers as part of a great ecology to serve a universal purpose, then human life has the potential to provide higher qualities of energies than other life forms. If these qualities can be produced through death or through conscious labours and intentional suffering, then human life has a clear purpose.
If Askokin is produced by death alone, it would seem that a human being simply returns to the Earth to be recycled - from "dust to dust" - and the energy liberated at death is automatically harvested. If there is anything left over from the debt of life that has been paid with a commensurate amount of Askokin, there may be a chance for some form of consciousness to continue.
Alternatively, if a human willingly undertakes conscious labours and intentional suffering, then these qualities of energies can be liberated during life, with no need to produce them at death as the debt (or much of it) has been paid. The 'surplus' Askokin can then be used to feed a more structured consciousness to continue after death.
In either case, the consciousness of human life serves cosmic purposes. The choice for an individual is simple, either attempt to serve consciously during life to produce something for oneself, or, serve unconsciously until death and roll the dice.
And another angel came out from the altar, which had power over fire; and cried with a loud cry to him that had the sharp sickle, saying, Thrust in thy sharp sickle, and gather the clusters of the vine of the earth; for her grapes are fully ripe. And the angel thrust in his sickle into the earth, and gathered the vine of the earth, and cast it into the great winepress of the wrath of God. Revelation 14:18-19 KJV