Which of the following scientists is credited with the idea that early life formed through a series of chemical reactions that make simple compounds more complex?

Stanley Miller is the scientist that is credited with the idea that early life formed through a successions of chemical reactions that make simple compounds more complex. He made a breakthrough of experiments in the origin of life by representing that a wide range of vital organic compounds can be produced by fairly simple chemical processes from inorganic substances. Although he worked with Urey on this experiment, Miller is far more well-known and credited for the discovery.

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.