Partnerships Implementing Engineering Education Worcester Polytechnic Institute Worcester Public Schools Supported by: National Science Foundation Life Sciences: 4.E.4 Seeds Part 1 of 3 Grade Level 4 Sessions Seasonality Instructional Mode(s) Team Size WPS Benchmarks MA Frameworks Key Words 45 minutes N/A Whole class N/A 04.SC.LS.06 04.SC.LS.07 04.SC.LS.08 3-5.LS.2 3-5.LS.3 3-5.LS.7 Seed, Soil, Root, Plant, Stem, Leaf, Dicot, Monocot Summary Students will be introduced to plants, plant parts, and seeds. The students will apply this knowledge to growing different seeds in different types of soil. At the end of this lesson the teacher will give a quiz. Learning Objectives 2002 Worcester Public Schools (WPS) Benchmarks for Grade 4 04.SC.LS.06 Compare and contrast the physical characteristics of plant or animals from widely different environments (desert vs. tropical plants; aquatic vs. terrestrial animals). Explore how each is adapted to its habitat. 04.SC.LS.07 Give examples of how changes in the environment (drought, cold) have caused some plants and animals to die or move to new locations (migration). 04.SC.LS.08 Investigate how invasive species out compete native plants (e.g., phragmites and purple loose-strife). Discuss how some native plants die as a result. Additional Learning Objectives 1. 3-5.LS.2 Identify the structures in plants (leaves, roots, flowers, stem, bark, wood) that are responsible for food production, support, water transport, reproduction, growth, and protection. 2. 3-5.LS.3 Recognize that plants and animals go through predictable life cycles that include birth, growth, development, reproduction, and death. 1 of 17
Partnerships Implementing Engineering Education Worcester Polytechnic Institute Worcester Public Schools Supported by: National Science Foundation 3. 3-5.LS.7 Give examples of how changes in the environment (drought, cold) have caused some plants and animals to die or move to new locations (migration). Required Background Knowledge None Essential Questions 1. What is the main function of the roots of a plant? 2. What is the main function of the leaves of a plant? 3. What is the difference between a dicot seed and a monocot seed? 4. What are the parts of a seed? 5. What does a seed need to grow? Introduction / Motivation Ask the students about their previous knowledge of seeds and a plant s reproductive process. Ask them if they have gardens at home and if so, what do they grow? Find out if they understand what it takes to grow a plant; that it needs water, light, and nutrients. During this first lesson the idea is to get all of the students up to the same basic level of plant and seed knowledge. Procedure The instructor will: 1. The teacher can present the information in any manner he/she wishes. The attached pages are meant to act as handouts for the students to read either before or after lecture. Materials List Materials per class Amount Location None N/A N/A Vocabulary with Definitions 1. Petiole connects the leaf to the stem 2. Veins carry nutrients and water through the leaf. 3. Blade the main part of the leaf. 2 of 17
Partnerships Implementing Engineering Education Worcester Polytechnic Institute Worcester Public Schools Supported by: National Science Foundation 4. Stomata tiny holes on the underside of the leaf that allow air to move in and out of the leaf. 5. Monocot the veins in the leaf are in parallel lines. Monocot sprouts have one leaf. 6. Dicot the veins in the leaf branch out from one another. Dicot sprouts have two leaves. 7. Stem the part of the plant that holds up the leaves. 8. Node the place where a leaf grows. 9. Green Stems die in the winter. (Some green stemmed plants live through the winter by using underground roots and grow new stems in the spring.) 10. Woody Stems live for many years. (The stems grow wider and taller with age. The stems grow thicker to support the height of the tree by adding a ring of cells around the trunk each year.) 11. Root usually grows underground. Roots absorb water and minerals from the soil by using root hairs. 12. Root hairs tiny structures that grow near the end of a root. 13. Root tip where the root ends. It has a slimy cap that helps it push through the soil. 14. Taproot the main root that is longer and thicker than the rest of the root system. Smaller roots branch off of it. 15. Fibrous Root network of branching roots with no main root. Most monocots have this type of system. Assessment / Evaluation of Students The instructor may assess the students in any/all of the following manners: 1. A graded quiz. Lesson Extensions 1. This lesson is intended to act as an introduction to plants (roots, leaves, seeds, and stems) to be followed by an experiment and engineering activity (see Seeds Lesson 2 and Seeds Lesson 3). 3 of 17
Partnerships Implementing Engineering Education Worcester Polytechnic Institute Worcester Public Schools Supported by: National Science Foundation Attachments 1. Reading Handout 2. Quiz Troubleshooting Tips None Safety Issues None Additional Resources None Key Words Seed, Plant, Stem, Leaf, Dicot, Monocot, Soil, Root 4 of 17
Leaves There are many different types of leaves. Most leaves have a petiole (pet l) which connects the leaf to the stem. Leaves also have veins to carry nutrients and water to the leaf. If you hold a leaf up to the light, you can usually see the veins. Different kinds of leaves have different patterns of veins. Some leaves have parallel veins and some leaves have branching veins. The main part of the leaf is called the blade. Although leaves can be many different colors, the blade of a leaf is usually green. A chemical called chlorophyll (klôrfil) is responsible for the green color. Leaves have tiny holes called stomata. They are located on the underside of leaves. Stomata are usually too small for you to see. The tiny stomata allow air to move in and out of the leaf. The part of grass growing above the ground is a leaf. A leaf can give you clues about other parts of the plant that you might
not be able to see. By examining a leaf, you can tell what kind of sprout the seeds of the plant will form and how many petals its flower might have. To predict what kind of sprouts and flowers a plant will have, find the veins in its leaves. If the veins are arranged next to each other, in parallel lines, the plant is a monocot. The word monocot tells you what to expect from the type of plant. Mono means one. Cot is short for cotyledon (kät l dn), the scientific name for the first leaf that sprouts from a seed. Monocot sprouts have petals in multiples of three. Plants with six or nine petals are monocots.
If the veins in the leaf branch out from one another, the plant is a dicot. The prefix di means two. Dicot sprouts have two leaves. Some dicots you might see in a vacant lot are buttercups and forget-me-nots. The flowers that dicots form have four or five petals. Dicots can also form flowers with a multiple of four or five petals. Flowers with eight or ten petals, for example, are dicots.
Everything needed for the new plant to grow is inside the seed. A tiny young plant, formed from the fertilized egg, is inside the seed. The seed also contains stored food that gives the tiny plant energy to grow. The plant uses the stored food until it can make its own food. Notice that the dicot seed contains more stored food than the monocot seed. Also, the dicot seed splits in two more easily than the monocot seed. The seed coat on the monocot seed is thicker than the seed coat on the dicot seed. How could this effect how quickly a young plant sprouts?
The function of the leaves is to use the sunlight they absorb to make food. This process is called photosynthesis (f t sin th sis). The word comes from two Greek words. Photo means light. Synthesis means putting together. During photosynthesis, plants use the sun s energy to combine water and a gas called carbon dioxide to make a kind of sugar. This sugar gives plants energy and the building blocks they need to grow. Oxygen, which is a gas, is released during photosynthesis. The oxygen is given off into the air. Photosynthesis takes place in tiny structures called chloroplasts. Chloroplasts can trap the sun s energy because they contain a chemical called chlorophyll. Chlorophyll is the chemical that gives leaves their green color. Stems
Some plants are tall and some are short. Tall plants have long stems, and short plants have short stems. The stem is the part of the plant that holds up the leaves. The plants leaves are attached to the stem. The place where a leaf grows is called a node. In some plants, only one leaf grows at a node. In other plants, two or more leaves grow at a node. Most stems grow upright. Some stems, however, grow along the ground. Others become attached to objects such as fences and wires. A climbing stem may grow along the surface of the object to which it is attached. Stems may branch out in many directions, or they may not branch out at all. Tree trunks are stems. They usually branch out a few feet above the ground. Some stems do not branch at all.2 A tree trunk is a stem that branches.3
The stems of a climbing plant, such as ivy, branch many times. Some stems, like the stem of a tulip, do not branch at all. This photo shows a climbing stem. 4 If you were to visit a vacant lot in the summer, you would see many plants with soft, green stems. If you returned to the same lot in the winter, you would not see many of these plants. This is because the stems and leaves have withered and died. Some of these plants, such as buttercups, leave behind seeds. The seeds will grow into new plants the next spring. Other plants with green stems, like dandelions, have underground roots that live through the winter and grow new stems the following spring. Most woody stems grow taller and wider as they age. Plants that have woody stems usually live for many years. Although they grow only during the spring and summer, they are alive in the winter. As woody plants grow taller, their stems grow thicker to support them. The stems add a ring of cells around the trunk each year. If a tree is cut down, you can figure out how old it was by counting the rings.
The rings give clues to what the weather was like while the tree was growing. During years when the weather was cold and dry, the rings of the trunk are narrow because the tree did not grow very much. During years when there was plenty of rainfall, the rings are thicker because the tree grew.
Stems have two important functions. First, they hold up the leaves of plants so that they are in the sunlight. Second, stems carry water, minerals, and food to different parts of the plant. Stems transport water, minerals, and food through tubes. There are two types of tubes. There are two types of tubes inside tree trunks and other stems. Each type of tube carries a different material. The xylem (zlm) carry water and minerals from the roots to the leaves. The phloem (flem) carry food from the leaves to other parts of the plant. In young, green stems, bundles of xylem and phloem are usually scattered through the stem. In woody stems, the phloem layer that carried the food through the tree is just below the outer layer of bark.
Roots In a vacant lot, you probably won t see a very important part of every plant. The root system of a plant usually grows underground. A plant s root system is made up of many roots and root hairs. Root hairs are tiny structures that grow near the end of a root. Root hairs absorb water and minerals from the soil. There are millions of root hairs on many plant roots. A root ends at the root tip. Root tips have slimy caps that help the roots to push through the soil as they grow. Root systems are usually as large as or larger than the rest of the plant. A large tree can have more than 500 root tips. Have you ever pulled plants out of the ground? If you have, you might have noticed that not all roots look the same. There are two types of roots. Some plants, such as dandelions, are hard to pull out of the ground. A dandelion has a long, thick root that grows deep into the soil. A main root that is longer and thicker than the rest of the root system is called a taproot. Smaller roots branch off of the taproot. Plants with taproots are typically dicots.
When you try to pull grass out of the ground, you get a tangle of skinny roots. Grass has a fibrous root system. A fibrous (fbrs) root system is a network of branching roots with no main root. Most monocots have fibrous root systems. Most plants with fibrous roots live for only one season. Many plants with taproots survive through the winter by storing food in their thick roots. The green part of the plant withers and dies in cold weather. When warm weather returns, a new stem, leaves, and flowers grow from the root.
References 1. Destinations in Science. Addison-Wesley Publishing. 1995. 2. http://www.photo.net/photo/pcd0796/flower-garden-downtown-munich- 36.tcl 3. http://www.bakerlite.co.uk/a_year_of_a_tree.htm 4. http://www.leeandkristin.net/annarbor/arb/ivy1.html
Name: Date Seeds on the Brain For each question below, please circle the correct answer for each question. 1. Which part of a plant takes in carbon dioxide? a. petals b. roots c. leaves d. pollen 2. Which part of a plant takes in minerals and water? e. petals f. roots g. leaves h. pollen 3. Which seed type sprouts with only one leaf? a. lima bean seed b. dicot seed c. tricot seed d. monocot seed For each of the following questions, please write TRUE or FALSE. 4. Carbon dioxide, which is a gas, is released during photosynthesis. 5. Food is stored inside of seeds to give the tiny plants energy to grow. 6. Seeds are carried by the wind to the location where they will grow.