Return to Unit D Main Page	Unit D Changes in Living Systems: Multimedia Segments Lesson 1.4 (DLSG*) A Field Study Simulation of a Local Ecosystem Chapter 1 Review Career Profile: Rehabilitating Injured Wildlife Lesson 2.1 (DLSG*) Succession on Land Lesson 2.1 (DLSG*) Aquatic Succession Lesson 2.2 Forest Harvesting *DLSG segments are designed for use with the Distance Learning Student Guide for this unit.