Skip Discover Education Main Navigation

6-8 > Plants
Grade level: 6-8 Subject: Plants Duration: One to two class periods
sections
Objectives | Materials | Procedures | Adaptations | Discussion Questions | Evaluation | Extensions | Suggested Readings | Links | Vocabulary | Academic Standards | Credit
print this lesson plan

Objectives
 



lesson plan support

Students will:
1. Understand the structure and function of roots, stems, and leaves.
2. Identify the parts of a plant by looking at an entire plant or a part of a plant.
3. Understand the importance of plants for animals’ (humans’) existence.
Materials

For this lesson, you will need:
Various market-fresh vegetables such as an uncut carrots, radishes, celery, broccoli, potatoes, sweet potatoes, spring onions, brussel sprouts, asparagus, beets, leeks, ginger, lettuce, parsley
Magnifying glass
Paring knife
Procedures

1. Discuss with students the four organs that are found on plants: roots, stems, leaves, and flowers. Concentrating on roots, stems, and leaves, have students describe the structure and function of each organ. Be sure you describe both their external and internal structures. Depending on the level of the student’s knowledge, actual plant tissue names can be discussed. Diagrams should be drawn or provided for students’ use.
2. Have students pick a plant and brainstorm a unique characteristic or adaptation of each plant organ, based on its habitat. Have them think about all the habitats that plants live in, such as deciduous forest, desert, ocean, freshwater, tropical rain forest, tundra, or grasslands. Have students choose one plant and its habitat and develop an explanation as to why that plant is able to survive with a particular adaptation. Climbing roots, food storage roots and stems, tendrils in vines, and carnivorous plants could all be possible examples. Students should describe the relationships between each of the plant organs and the environment.
3. As a class or in small groups, have students observe, classify, and dissect a number of examples of plant organs that have been obtained from the supermarket. Students should observe each vegetable, describe both its external and internal structure in detail, determine what plant part the vegetable represents, and describe the plant function. If working as groups, students will need to present their knowledge to the entire class.
4. Along with providing students with some obvious examples of plant organs, students should also observe some adaptations of plant organs and be able to explain how that adaptation serves the plant. An example of this would be potatoes classified as stems.
5. Discuss with the students which plant parts were easy to identify and which were difficult. What vegetables contained more than one plant organ? Did any vegetable parts show a useful adaptation for the plant? What variations were found within the same plant organ?
Back to Top
Adaptations

Adaptation for older students:
Have students prepare thin tissue samples to study under a dissecting or compound microscope. Students should be able to identify tissue types that vary between the three vegetative organs of a plant (mesophyll, pith, cambium, xylem, and phloem).
Back to Top
Discussion Questions

1. What plant organ do you think you eat the most? Is it a root, stem, leaf, or flower?
2. Compare and contrast the structure and function of the vegetative plant organs studied. What structures were similar in each organ? What functions did they have in common? What characteristics of each organ could you easily identify when you studied the vegetables? What accounts for the differences in functions of different organs in the same plant? What do you think would happen to a plant’s survivability if one or more of its organs changed—through genetic enhancement, for example?
3. After studying roots, stems, and leaves, discuss how each of these plant organs can adapt to different environments. Discuss examples of an adaptation for each organ.
4. Chose an extreme environment and find out what type of plants live there. What features do the plant organs have that enable them to survive in a swamp, river, desert, or ice cap?
5. Debate whether humans should genetically alter crops and the vegetables that are harvested. Should the United States import and export these crops?
6. Are certain plants endangered in your area? Why do endangered animals receive more support and press than endangered plants? Should they?
7. Discuss how plants can help society and the world. What are some uses other than food for plant organs? Provide as many examples as possible.
Back to Top
Evaluation

Have students present what they’ve learned in oral presentations, posters, computer visual presentations, models, or even as games. Students should be evaluated on the accuracy of the scientific information they present; whether they have included accurately detailed diagrams; their ability to show an understanding of a plant organ’s function; and an understanding of how a plant organ relates to the other parts of the plant.
Back to Top
Extensions

Tree Rings
Obtain cuts from a tree or from various trees (e.g., firewood) to study the annual ring patterns. Where are the rings close together? Are there any scars in the rings? Can you hypothesize why the scars were made? What environmental conditions and changes can be interpreted using tree rings (climate, pollution, etc.)? Calculate how old the trees were.

Simple Seed Experiment
Plant four seeds facing different directions in a clear container (petri dish, glass) near a light source. Each seed should be planted right side up, root facing down. The four seeds should be facing north, south, east, and west, respectively. Support the seeds with filter paper, paper towel, or cotton balls, and water the seeds well. Observe the seed growth over the course of a week. Record the direction of stem growth and root growth from each seed. Did the direction the seed was facing influence the growth?

Labeling a Salad Bar
Create a salad bar with an assortment of plant samples and have students label the organs of each. Students should take one of each sample and develop a means of testing its water content. Once the results have been obtained, they should write the measured water content on each sample’s label. Next, invite class members to load up their plates with healthy veggies! Before dining, students should weigh the total contents of their plates and estimate the total water content. While enjoying their salads, students can share estimates of what percentage of the water they consume each day comes from plants.

Back to Top
Suggested Readings

Plant Survival: Adapting to a Hostile World
Bruce Capon. Timber Press, 1994.
By finding ingenious ways to provide themselves with nutrients, water, and sunlight, plants have adapted to an amazing variety of harsh environments. This book details how plants survive intense competition and the extremes of harsh winters, bone-dry deserts, and total immersion in water.

Science Fair Success with Plants
Phyllis J. Perry. Enslow, 1999.
You’ll find a variety of simple experiments in this book that demonstrate how changes in a plant’s environment, such as amount of light or make-up of the soil, affect its growth and health. Other experiments show how plants’ life processes work, from how water moves within plants to how they reproduce.

Back to Top
Links

Plants and Their Structure
Text and great graphics of plants

Greenhouse Tour - Carnivorous Plants
Photos and info on carnivorous plant adaptations

The Great Plant Escape
Student game and teachers’ guide for information on plants

Photosynthesis
Lots of links to sites on photosynthesis for teachers and students

American Forests
Home page for American Forests; Big Tree listing, global releaf project, global climate change/tree relationship

Back to Top
Vocabulary

Click on any of the vocabulary words below to hear them pronounced and used in a sentence.

speaker    annual ring
Definition:The layer of wood formed in a plant in a single year.
Context:Every year trees make wood in concentric rings in their stems. Each annual ring corresponds to a year of growth in a tree’s life.

speaker    chlorophyll
Definition:Green pigments found in photosynthetic organisms.
Context:All plant cells contain the green pigment chlorophyll, which is a necessary chemical for the process of photosynthesis.

speaker    midrib
Definition:The central vein of a leaf.
Context:Many plant leaves are classified based on the pattern of the midrib and branching leaf veins.

speaker    terminal bud
Definition:The undeveloped shoot, leaf, or flower growing or appearing at the end of a stem.
Context:Terminal buds are found at the tips of stems and form every growing season. These buds remain tightly closed through the winter months and open to form new leaves, and possibly flowers, in the spring.

Back to Top
Standards

This lesson plan may be used to address the academic standards listed below. These standards are drawn from Content Knowledge: A Compendium of Standards and Benchmarks for K-12 Education: 2nd Edition and have been provided courtesy of theMid-continent Research for Education and Learningin Aurora, Colorado.
 
Grade level:6-8
Subject area:Science
Standard:
Knows about the diversity and unity that characterize life.
Benchmarks:
Knows that animals and plants have a great variety of body plans and internal structures that serve specific functions for survival (e.g., digestive structures in vertebrates, invertebrates, unicellular organisms, and plants).

Grade level:6-8
Subject area:Science
Standard:
Knows about the diversity and unity that characterize life.
Benchmarks:
Knows evidence that supports the idea that there is unity among organisms despite the fact that some species look very different (e.g., similarity of internal structures in different organisms, similarity of chemical processes in different organisms, evidence of common ancestry).

Grade level:6-8
Subject area:Science
Standard:
Knows the general structure and functions of cells in organisms.
Benchmarks:
Knows the levels of organization in living systems, including cells, tissues, organs, organ systems, whole organisms, and ecosystems, and the complementary nature of structure and function at each level.

Grade level:6-8
Subject area:Science
Standard:
Knows the general structure and functions of cells in organisms.
Benchmarks:
Knows that multicellular organisms have a variety of specialized cells, tissues, organs, and organ systems that perform specialized functions (e.g., digestion, respiration, reproduction, circulation, excretion, movement, control and coordination, protection from disease).

Back to Top
Credit

Mary C. Cahill, middle school science coordinator, Potomac School, McLean, Virginia.
Back to Top