Scientific names are given to any organism to classify them in a standardized manner. Generally two word names (binomial nomenclature) are given to organisms. Since these are standardized names, i.e. only one name is given to a organism, it can be used unambiguously around the world to refer to the same animal. An organism may be called by a local name in a given region (and in a regional language) and it may get very confusing while looking at the ecosystem (entire earth) as a whole. Scientific names prevent that confusion.
Scientific names also allows for precision naming. A local name may be used for all the organisms of that class (say snakes, think how many different types of snakes are there, but all are referred to as snakes), which creates confusion in identifying individual subclass. Scientific names prevent this as well.
Scientific naming also enables understanding of relationship between organism classes. For example, cats and lions are from same family (felidae), just different sub-families and hence will share some part of their scientific names.
Hope this helps.