hi,

see after completing bsc course, you may apply for different government and private organization job where graduation is needed, for example like bank po, clerk, office executive, customer carer representative , relationship manager etc, however if you want to research oriented job or core sector job related with your discipline you have to do post graduation. however msc zoology candidates may wok as a quality assurance officer in biotechnology industry, may work as a lecturer in school and colleges, may work a analyst in museum.