What is the practice of classifying organisms called?

Taxonomy

In science, the practice of classifying organisms is called taxonomy (Taxis means arrangement and nomos mean method).

And,

The modern taxonomic system was developed by the Swedish botanist Carolus Linnaeus (1707-1778). Hope this helps..

Good Luck

sheep is a herbivore animal whereas grasshopper belongs to the class chordates but both of them feed on greens.  

if grasshopper and sheep feeding on a pasture land, i do not think both of them will have any impact on each other. however, the number of the species can make difference. since sheep feed on greens, there is a possibility there left no pasture land for the grasshoppers or they may get extinct.

1. efficient use of space

2. elimination of groundwater contamination

3. energy generation

4. lower carbon footprint