Leaf+Arrangements


 * LEAF ARRANGEMENTS**
 * LISTENING REVIEWEXERCIS E(Skills 1 through 6)**
 * //175//**
 * Questions 1 through 6. Listen to a lecture in a botany**

Phyllotaxy is a scientific term that refers to the arrangement of leaves on the stem of a plant. On most plants, leaves are arranged in a definite pattern. It's very unusual for a plant to have randomly placed leaves. One of the main reasons why the leaves on a plant stem are arranged in an orderly way is to ensure that each leaf is exposed to the maximum amount of light with a minimum amount of interference from other leaves. The first type of leaf arrangement is the alternate arrangement. In this type of leaf arrangement, there's only one leaf at each node, and a node, by the way, is the spot where the leaf's attached to the stem. The next type of leaf arrangement is the opposite arrangement. In this type of leaf arrangement, there're two leaves at each node, and these two leaves are opposite each other on the stem. This type of leaf arrangement is not as common as the alternate arrangement, with one leaf at each node. The last type of leaf arrangement is called the whorled leaf arrangement. This type of leaf arrangement is the least common of all. It is not as common as either the opposite or the laternate arrangement. In this type of arrangement, in the whorled arrangement, three or more leaves are attached to the stalk of the plant at the same node.
 * 0Today, we're going to talk about phyllotaxy. Phyllotaxy is a scientific**
 * term that refers to the arrangement of leaves on the stem of a plant. On most plants, leaves are arranged in a definite pattern. It's very unusual for a plant to have randomly placed leaves. One of the main reasons why the leaves on a plant stem are arranged in an orderly way is**
 * to ensure that each leaf is exposed to the maximum amount of light with a minimum amount of interference from other leaves.**
 * e The first type of leaf arrangement is the**
 * alternate arrangement. You can see this**
 * type of leaf arrangement in the diagram.**
 * In this type of leaf arrangement, there's only one leaf at each node, and a node, by the way, is the spot where the leafs attached to the stem.**
 * e The next type of leaf arrangement is**
 * the opposite arrangement, which you can**
 * see in the diagram. In this type of leaf arrangement, there're two leaves at each node, and these two leaves are opposite**
 * each other on the stem. This type of leaf**
 * arrangement isn't as common as the alternate arrangement, with one leaf at eac.hnode.**
 * o Where was I? Oh, OK. The last type of**
 * leaf arrangement that we're going to look**
 * at is called the whorled leaf arrangement. This type of leaf arrangement is the**
 * least common of all. It isn't as common**
 * as either the opposite or the alternate arrangement. In this type of arrangement, in the whorled arrangement, three or**
 * more leaves are attached to the stalk of the plant at the same node. In the diagram, you can see three leaves at**
 * the same node, but it's also possible for there to be more than three leaves at the same node, and the leaf arrangement would still be considered a whorled arrangement.**
 * e Now, ... Ihope you've been paying**
 * careful attention to this information**
 * about phyllotaxy, ... because I ...um ...**
 * have an assignment for you that's a bit different from the homework assignments**
 * you've had so far. Your assignment is to visit the universitys botanical garden. Were you aware that this university has quite an extensive botanical garden? In the botanical garden, there're examples of many different kinds of plants, and**
 * each plant is labeled with the name of the**
 * plant as well as other information about the plant. For your assignment, you are to find three examples of each of these different types of leaf structures, write down the names of the plants that have these leaf structures, and then turn in**
 * your lists on Friday. It'll be quite easy for you to find examples of the alternate leaf structure because, as Isaid before, this is the most common type of leaf structure. It'll be a bit more difficult to find**
 * examples of the opposite structure, but by**
 * far the most difficult leaf arrangement for you to find will be the whorled structure because this leaf arrangement's so rare. You11have to spend some time finding examples of the whorled leaf arrangement in our botanical garden. See you on**
 * Friday with your lists ... eh ... uh ...**
 * Hold on for a minute! Just a word of warning .... You'd better not put off the assignment until Thursday evening, as I'm sure many of you are used to doing. The botanical gardens close at sunset each day, so if you try to put this assignment**
 * off until Thursday evening, you won't be**
 * able to get it done.**
 * 1. WHY IS THE PROFESSOR DISCUSSING LEAF ARRANGEMENTS WITH THE STUDENTS?**
 * 2. WHAT POINTS DOES THE PROFESSOR WANT TO MAKE ABOUT LEAF ARRANGEMENTS ON PLANTS?**
 * 3. DRAG THE APPROPRIATE DESCRIPTION OF**
 * EACH TYPE OF LEAF ARRANGEMENT TO THE BOX BELOW THE NAME OF THE LEAF Al\P.ANGEM."E.Nl.**
 * 4. DRAG THE APPROPRIATE DESCRIPTION OF LEAF ARRANGEMENT OCCURRENCES TO THE BOX BELOW THE NAME Of THE LEAF ARRANGEMENT.**
 * S. WHAT DOES THE PROFESSOR SAY ABOUT THE BOTANICAL GARDEN?**
 * 6. LISTEN AGAIN TO PART OF THE LECTURE. THEN ANSWER THE QUESTION.**
 * //(professor)// See you on Friday with your lists ....**
 * Eh ... uh ... Hold on for a minute! Just a word of warning .... You'd better not put off the assignment until Thursday**
 * evening, as I'm sure many of you are used to doing.**
 * WHAT DOES THE PROFESSOR MEAN WHEN HE SAYS THIS:**
 * //(professor)// Hold on for a minute!**

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