Also, classes in forest management, GIS ArcView, radio telemetry, wildlife management, and writing classes will be of great value. During your summer breaks, spend a few months each year working seasonal biology jobs.
Many universities hire seasonal biologists with degrees and who are still working on their degrees.
I have worked with two different engineering firms over the last couple of years. Many job announcements I have seen usually require a MS or a BS and a number of years experience involving wetlands, protected species, writing Environmental Assessments and Environmental Impact Statements, etc. My coworkers from both firms had MS degrees and were able to get their permanent job without having to do very many years of seasonal work. Most firms like to have staff with MS degrees since these people make the firm look better to prospective clients. Be warned, these jobs are also highly competitive, but as we humans screw with the environment more and more, there will always be more of these jobs opening up as long as we want flush toilets, drinking water, strip malls, highways, landfills, subdivisions, etc.