The requirements are to complete high school as to enroll in a bachelor's degree program. Biologists must have a 4year undergraduate degree, such as a Bachelor of Science in Biology, for entry-level research positions. Some classes to take are microbiology, biochemistry and molecular biology. employers prefer biologists with a Master of Science in Biology or in any life sciences when working in applied research, product development, management or teaching in the high school level. If you wish to conduct independent research or teach in a university setting must have a doctorate degree in biology or a closely related field.
information from: http://degreedirectory.org/articles/Biologist_Career_Definition_Job_Outlook_and_Education_Requirements.html