What is the best basis for analyzing/mapping evolutionary hostory

https://en.wikipedia.org/wiki/Phylogenetic_tree. Try this link.

Explanation:

The best basis for mapping evolutionary history would be a phylogenetic tree.  This "tree" shows the relationship between every biological species on Earth in reference to their origin...In evolutionary terms, a common ancestor. This tree also takes into consideration the genetic and physical traits and differences in every species and organism on the tree. Hope this helps : )!

well you should start maybe a time line OR,  In the case of phylogeny, evolutionary investigations focus on two types of ... a high percentage of bases in the same locations, causing these organisms to appear ... history of species, our own included, phylogenetic analysis has ... made recommendations for conservation

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.

that's all i luck!