This lesson might work best introduced in small bites over several days. The "river newspaper" exercise in the Assessment will probably be most effective if it is approached as a project of a week or so, culminating in the actual "publication" on a day of significance to the students (., last day before winter break; Earth Day).
You should familiarize yourself with Communicating Ecosystem Services , made available through the Ecological Society of America and the Union of Concerned Scientists.
There are many resources on water and water purification. Thorough writings on ecosystem services, however, are just beginning to emerge. See Additional Resources for several print resources on this topic.
While they all have the three elements of a domain, a community, and a practice, they come in a variety of forms. Some are quite small; some are very large, often with a core group and many peripheral members. Some are local and some cover the globe. Some meet mainly face-to-face, some mostly online. Some are within an organization and some include members from various organizations. Some are formally recognized, often supported with a budget; and some are completely informal and even invisible.
Figure 3: Webkit main flow
Figure 4: Mozilla's Gecko rendering engine main flow( ) From figures 3 and 4 you can see that although Webkit and Gecko use slightly different terminology, the flow is basically the same.
Gecko calls the tree of visually formatted elements - Frame tree. Each element is a frame. Webkit uses the term "Render Tree" and it consists of "Render Objects". Webkit uses the term "layout" for the placing of elements, while Gecko calls it "Reflow". "Attachment" is Webkit's term for connecting DOM nodes and visual information to create the render tree. A minor non semantic difference is that Gecko has an extra layer between the HTML and the DOM tree. It is called the "content sink" and is a factory for making DOM elements. We will talk about each part of the flow: Parsing - general Since parsing is a very significant process within the rendering engine, we will go into it a little more deeply. Let's begin with a little introduction about parsing.