【正文】 t a difficult task. Now how do you think this affected their lives? Stu: Well if they could travel so easily over such a large area, they could trade with people from other areas which I guess would lead them to form alliances ? Pro: Exactly. Having an efficient means of transportation, well, that helps the Iroquois to form a federation linked by natural waterways. And this federation expanded from what is now Southern Canada all the way south to the Dalever River. And this efficiency of birch bark canoe also made an impression on newers of the area. French traders in the 17th century modeled their...well they adopted the design of Yreka?s birch bark canoes, and they found they could travel great distances more than 15 kilometers a month. Now besides the bark, Native Americans also used the wood of the birch tree. The young trees were used to support for loggings with the waterproof bark used as roofing. Branches were folded into snow shoes and the Native American people were all adept to running very fast over the snow in these birch brand snow shoes which if you ever tried walking in snow shoes you know wasn39。s what the Native Americans did. They would peel large sheets of bark from the tree to form lightweight yet sturdy canoes. The bark was stretched over frames made from tree branches, stitched together and sealed with resin. You know that sticky liquid that es out of the tree? And when it dries, it39。s one of the great things of birch bark. The taste of the birch tree doesn39。, another layer a tougher inner layer of the tree adheres to the bark, producing a stronger material. So the winter bark was used for larger utensils and containers. Stu: I know people make utensils out of wood, but utensils out of tree bark? Pro: Well, birch bark is pliable and very easy to bend. The Native Americans would cut the bark and fold it into any shape they needed, then secure with cords until it dried. They could fold the bark into many shapes. Stu: So if they cooked in bowls made of birch bark, wouldn39。re going to focus on Iroquois and Hooray peoples. They lived in the northeastern great lakes region of North America. Now, back then, their lives depended on the natural resources of the forests, especially the birch tree. The birch tree can grow in many different types of soils and it39。ve been very helpful. Thanks. Pro: Anytime. Bye Stu: Bye. Lecture Pro: So we39。ll need photo copiers too. There is down the hall to the left. We have system where you have to use copy cards so you39。s great! At my last school, it takes really a long time to get the materials I needed. So when I had a project, I had to make a plan away in advance. This sounds much faster. Another thing I was wondering is: is there a place where I can bring my puter and hook it up? Pro: Sure. There is a whole area here on the main floor where you can bring a laptop and plug it in for power but on top of that we also have a connection for the inter that every seat. Stu: Nice, so I can do the all research I need to do right here in the library. All I have the resources, all the books and the information I need right here in one place. Pro: Yeah. That39。s the section where we have language, literature and arts. And if you go down stairs you will find history section. Generally, the students who concentrated in Latin American literature find themselves research in history section a lot. Stu: Hum, you are right. I am a transfer student and I39。m wondering if you can give me a few quick points just about library. I?d really appreciate it. Pro: Sure. I will be glad to. What39。 this means that when the bat approaches, the moth can detect the bat?s presence. So, it has time to escape to safety, or else they can just remain motionless. Since, when they stop meeting their wings, they will be much hard for the bat to distinguish from, oh… a leave or some other object. Now, we have tended to underestimate just how sophisticated the ability that animals that use ultrasound are. In fact, we kinds of assume that they were filtering a lot out. The ways are sophisticated radar on our system can ignore the echo from the stationary object on the ground. Radar are does this to remove ground clutter , information about the hills or buildings that they doesn?t need. But bats, we thought they were filtering out kinds of information, because they simply couldn?t analyze it. But, it looks as we are wrong. Recent there was the experiment with trees a