The purposes will vary slightly from belief system to belief system. Writings such as the Judeo-Christian Bible and/or the Moslem Koran will in of themselves have more of a noble purpose. Peace, prosperity, fertility, brotherhood, to name a few. However, later human interpretations of these early books will usually loose the original meanings. Influenced by the current governmental systems in charge; purposes such as conquest, conversion (religious), territorial expansion; are added to the list. If Jesus saw what we were doing in his name after 2000 years, he’d spin in his grave fast enough to power New York City! (Theoretically of course, the Christians believe he rose into Heaven).
The purpose for animals, you know the answer - TO SERVE MAN…
Why? This I answered in the “Religion” thread topic…