The first 57 pages of the UbD Professional Development Workbook introduce three different templates for "backward design" of an instructional unit: a brief 1-page template, a somewhat more detailed 2-page version, and a very detailed 6-page breakdown that gets into the details of day-by-day lesson planning. The remaining pages are mostly taken up by examples of unit plans in everything from science to history to English.
After looking through the different designs, I've decided to go with the 2-page version for planning my ecology unit. It gives a bit more space to describe different portions of the unit than the 1-page version, especially for the Stage 3 tasks and lessons. The 6-page version looks too detailed and complex for my first attempt at unit design; I don't want to fall into "paralysis by analysis." I'll stick with the 2-pager for now and expand my ideas as necessary once I have a basic framework in place.