Howard-Tilton Memorial Library collects materials that support the teaching and research programs of the university's Department of Ecology and Evolutionary Biology. The department offers programs of study leading to the Bachelor of Science, Master of Science, and Doctorate degrees in Ecology and Evolutionary Biology. The department also offers an undergraduate major in Environmental Biology. The department of Ecology & Evolutionary Biology emphasizes three main areas of academic inquiry: tropical biology, wetlands ecology, and global change biology. More specifically, studies of organisms, populations, communities, ecosystems and global systems focus on conservation biology, ecosystem ecology, environmental biology, evolutionary biology, global change, tropical ecology, and systematics. Research is centered geographically in the subtropics — especially Louisiana — and the tropics.