The selection and elevation of holy sparks is a product of the sin of Adam HaRishon. After he sinned, he was dispersed into many facets of creation and souls; we are essentially cells from within his entire being and essence.
Since then we are summoned to raise these sparks from the four general ranks in creation; inanimate, vegetation, living and man. It is in the Beit HaMikdash where we can correct and refine these sparks in the loftiest way. Each rank represents one of the four worlds of creation.
The salt used for the korbanot elevates the world of the inanimate. The first fruits raise the sparks found in the vegetation world. The animals which are the aspect of the living category elevate the rank of living. Israel who represents the entire world raises the sparks on the level of man. In this way all parts of creation are refined and corrected.
This is deeply missing today. Our Rabbis teach us that prayer replaces part of the avodah of Bikkurim as we are able to rectify some of these energies in this way. Tefillah enables us to elevate the four worlds, however not to fully correct them. This can only occur through the Beit HaMikdash and korbanot; this is the only way we can perfect creation in its entirety.