Below is a general shape of e^-x and also e^x side by side for comparison:
as you can see they are just flipped versions of one another as one would expect.
Now, to answer the question why is e^0= 1? Well that is because any number raised to the power of 0 will equal one:
ie. x^0 = 1 (where x is any number)
e is just another constant in mathematics, such as pi.
e = approximately 2.71828
therefore, e^-1 = 2.71828^-1 = 0.3678, which is just a single point or dot.