【正文】 itical species that keeps the system going. Now, beaver populations are on the rise again, but there is something to think about. Consider humans as part of these ecosystems, you39。t live in running water, and then the birds and animals that eat them, lose their foods supply. Professor: Precisely, so the beaver in this ecosystem is what we call a keystone species. The term keystone kind of explains itself. In architecture, a keystone in an archway or doorway is the stone that holds the whole thing together, and keeps it from collapsing. Well, that39。t there? Student: You just have a regular running stream, because there is no dam, so the ecosystem would be pletely different, there would be fewer wetlands. Professor: Exactly, so, now let39。s something about wetland, and ground water too. Professor: OK, good. Wetlands have a big affect on ground water, the amount of water below the surface of the land. Think of wetlands as, Umm, like a giant sponge, the earth soaks up a lot of this water that39。s like there is more standing water, more Stillwater around, and that water is a lot cleaner than swiftly flowing water, because the dirt and settlement and stuff has the chance to sink to the bottom. Professor: More important for our discussion, wetland areas support a lot more variety of life than swiftly flowing water. For example, there are more varieties of fish or insects, lots of frog spices, and then species that rely on those species start to live near the wetlands too. Student: Yes, like birds and mammals that eat the fish and insects, and you can get trees and plants that begin to grow near the standing water, that can39。t until a convention center and a parking garage was built about decades later that malls started to be successful. TPO 13 – Lecture 2 Narrator: Listen to a part of a lecture in an ecology class. Professor: So, continuing our discussion of ecological systems whole systems. The main thing to keep in mind here is the interrelationships. The species in the system err…. and even the landscape itself, they are interdependent. Let’s take what you’ve read for this weekend and see if we can apply this interdependence idea. Mike? Student: Well, um…, how about b eavers ecosystems with beavers in waterways. Professor: Good, good, go on. Student: Like, well, you can see how it39。t necessarily inc lude things like sculptures or decorative walkways or… or even eye catching window displays, you know art. Although I bet the first to admen those things are ascetically appealing, however, visually pleasing sights, while there are not a part of pedestrian malls design that matter than most. The key consideration is a pact and convenient layout. One which allows pedestrians to walk from one end of the mall to the other in just a few minutes, so you can get the major stores, restraints and other central places without having to take more than one or two turns. Now, this takes a careful uncreative planning. But now what if one ingredient to this planning recipe is missing? There could quite be possibly long lasting effects. And I think a good example is pedestrian mall in the Louisville Kentucky for instance. Now when the Louisville mall was built, it has lots of visual appeal, it was attractively designed, right in the small part of downtown and it pretty much possessed other design elements for success. But now, here is my point about location es into play. There wasn39。s where access to the public transportation es in, if… if the designer planed to locate the malls in central transportation hub, like bus terminal, a major train, subway station or they work with city officials to create sufficient parking areas, not too far from the mall, which make sense because people can drive into the mall area or then they need easy access to it. OK, so that39。s we39。 you’ll note that in your paper. See, your paper should pare what is expected of children at certain stages of development with what you actually observed. Student: Ok, I have one more question now. Professor: What’s that? Student: Where can I find a child to observe? Professor: Ur, I suggest you contact the education department secretary. She has a list of contacts at various schools and with certain families who are somehow connected to the university. Sometimes they are willing to help out students with projects like yours. Student: Ok, I’ll stop by the educational department office this afternoon. Professor: And if you have any trouble or any more questions, feel free to e by during my office hours. TPO 13 – Lecture 1 Narrator: Listen to the lecture in the city planning class. Professor: In the last 15 years or so, many American cities have had difficulties in maintaining a successful retail environment. Business owners in the city centers or the downtown areas have experienced some financial losses, because of the city movement of th