How hard is it to get a job in Yellowstone National Park?

I really want to get a job in yellowstone. I would love to do something with wildlife or where i could at least see the wildlife. Ultimately I want to be a wildlife biologist but i have to have a degree to do that, so what jobs are available for an 18 year old there? I figure if i can at least get my foot in the door it might be easier to get a job elsewhere later. How hard is it to get a job in yellowstone? Does anyone know about how much jobs pay there on average?