Animals live in populations. Groups of populations inhabiting the same area make up biological communities. Processes operating at these levels control the biodiversity of habitats and regions. This subject presents the conceptual framework needed to understand these processes and illustrates that framework whenever possible using examples from rainforest populations and communities, which are among the most complex and interesting ecological systems in existence. Topics presented include population growth, species interactions, community patterns and dynamics, food webs and the effects of disturbance and scaling on diversity. An extended field trip to the zoology and tropical ecology field station at Kirrama allows students to look firsthand at these systems and the animals inhabiting them and see how they interact.