Geology or Biology?
Paleontologists straddle two worlds. The fossils we study come from the ground, and this geological context is important for better understanding the prehistoric environment. Yet, we also need to understand the biology of the now-dead organisms - all of those protuberances used to define species are muscle scars, or neurovascular foramina, or *something* that once had soft tissue. Unfortunately, it's also difficult to be a "jack of all trades." Paleontology graduate programs typically are housed in geology, anatomy, or biology departments, and your choice in this matter will have huge ramifications.
Why Does the Department Matter?
In the simplest sense, the type of department will dictate the types of classes you take in graduate school. Don't count on getting the opportunity to take strat-sed in a biology program. In a broader sense, it will dictate the types of resources and faculty at your disposal. A geology department is far more likely to have access to good thin-section equipment, the toys needed for rare earth element analysis, and experts in taphonomy or sedimentology. By contrast, a biology or anatomy department will probably have more to offer for dissecting facilities, soft tissue histology equipment, and experts in anatomy or functional morphology. So, department focus will generally (but not always) offer opportunities and constraints unique to the discipline. As noted below, your training will also define the types of positions for which you can apply later on.
Help! I Don't Have a Background in [Biology / Geology]!
This depends completely on the school and the individual. I originally wrote off my current anatomy department, because I was coming from a geology undergrad program. I didn't think they would ever want or consider a student who didn't have many biology courses - yet, it has mattered very little in the long-run. There's really no adequate preparation for human gross anatomy (other than to just take the course)! For me, and many others, it's been no problem to make the jump from geology to biology. I know fewer who have gone the other way, but that's probably just a sampling bias. In any event, don't write off a program if you are truly interested! Many departments are willing and able to help you fill any gaps in your knowledge, and it's best to talk to someone in the program itself to find out their expectations.
The most important thing to consider in this regard is where you see yourself in 20 years. Both geology or biology backgrounds probably offer equal opportunity for entry into the museum world, but if you're chasing after university-level jobs, give this topic careful consideration. Do you want to be in a geology department? An anatomy department? An evolutionary biology department?
I have a strong personal bias towards anatomical paleontology (just to be upfront). When choosing a graduate school, I saw much better job prospects with a background in anatomy. I could find a home in a biology, anatomy, or even possibly geology department (if they were more interested in a paleontologist than a stratigrapher). Anatomy offers the option of landing a job at a medical school (teaching gross anatomy), or teaching anat-phys at a liberal arts school, or finding a museum job. The options seemed narrower, and the job market smaller, for geology. Additionally, my research interests (understanding dinosaurian anatomy and paleobiology) were much more appropriate for a biology or anatomy department - I didn't feel that I would necessarily get the resources that I needed in the (quite excellent otherwise) geology departments to which I applied. Finally, I felt like I wasn't constrained when it came down to the final job search. I was able to apply for anatomy, geology, and museum jobs (with some success). So, there are no regrets in my mind about the course of action I followed.
Ultimately, the decision is up to you. Readers: feel free to chime in with your own thoughts!
Up next: Miscellanea Part I - Location, Size, Timing, and Job Prospects