In the arena of developmental and stem cell biology, you could study microbial pathogenesis, endocrinology, cardiovascular biology, cancer biology, cell signaling, cellular specification and differentiation, organogenesis, tissue morphogenesis, or cell-cell signaling during development. You would be working with a variety of model organisms in your graduate work, including worms, flies, fish, frogs, chickens, and mice, as well as human-derived tissues.
If immunology, bacteriology, parasitology, virology, and public health epidemiology are more aligned with your interests, then look to spend a fair amount of time conducting independent research and preparation of an original thesis as part of your biological sciences graduate program.
If the great outdoors are more your style, look for a masters degree or PhD in fieldwork studying the biological requirements for the survival of endangered and non-endangered species or habitats. Expect the research project to last between three to five years in the field and lab.
Additional graduate course work in the biological sciences is expected to round out your education and support your background and research. The coursework is selected jointly by you and your advisor and is made within the guidelines of the graduate advisory committee.
If your master's degree is in the same field as your bachelor's degree, then you might not have to take many additional classes and can jump right into the research. Master's degrees in the biological sciences typically take between two to four years to complete.
For some PhDs, expect the first two years to be primarily coursework. After that, expect to study for your qualifier, which is a test your advisors use to see if you are ready to conduct PhD-level research. Once your qualifier is accepted, the remainder of the graduate work is research.