GRADE: Seventh

CONTENT STANDARD: Life Science

CONTENT TOPIC: Diversity And Adaptations Of Organisms

CONCEPT: Plants are classified according to various structures.

CONTENT OBJECTIVE: 7H3.00 To understand the development of plants and their systems

INSTRUCTIONAL OBJECTIVES: The learner will:

3.01 define the parts and purposes of a vascular system in plants.
3.02 explain the difference in xylem tissues and phloem tissues for conduction of materials.
3.03 draw and label the parts of a root system in vascular plant.
3.04 observe the different types of roots.
3.05 determine the differences in the two types of stems: herbaceous and woody.
3.06 examine examples of herbaceous stems and woody stems.
3.07 define the specialized types of stems such as rhizomes.
3.08 define the terms annual, biennial and perennial.
3.09 observe an experiment to show the xylem in a stem.
3.10 draw and label the cross-section of a leaf's tissues.
3.11 draw and label the process of photosynthesis in a leaf.
3.12 write the chemical formula for photosynthesis.
3.13 explain the differences in plant respiration and photosynthesis.
3.14 define plant tropism and the role of auxin in plant behavior.

I. Roots
A. Purposes
B. Parts of a root
C. Types of roots
II. Stems
A. Purposes
B. Parts of a stem
C. Types of stems
III. Life spans for plants
IV. Leaf
A. Arts of a leaf
B. Photosynthesis
C. Respiration
V. Plant tropism

TN COMPONENT OF SCIENCE: Process of Science

TN GOAL:

To enable students to demonstrate the process of science by posing questions and investigating phenomena through language, methods and instruments of science.

1.1 Observing - The senses are used to develop an awareness of an event or object and the properties thereof.

1.1a Observing is a process used to develop an awareness of the surrounding environment.

BENCHMARK:By incorporating prior knowledge with the process of observation, a better understanding of one's environment may develop.

TIME REQUIRED:

5 days of instruction and observations

Roots - carrot, ivy, grass, corn plant, stems - Johnson grass or Bermuda grass, rhizomes, potato tuber, celery, wood stem, photosynthesis drawing - celery, food coloring, water, breaker, plants, window or other light source

Auxins, diffusion, flexible, herbaceous, osmosis, palisade layer, phloem, primary root, rhizome, root hair, secondary roots, spongy layer, stomata, tropism, tuber, woody, xylem

We will be studying about plants and the parts of a plant. We have previously studied the different categories or classification of the plants. We will now examine the vascular plants We will learn and observe the different parts of the plant and some of the processes occurring in plants. Who remembers and can explain what I mean by the term vascular plant? (response) What do you use in your body to compare to a plants vascular system? (response)

(The following activities have been incorporated into the lesson:

1. Place a stalk of celery in a beaker of colored water. Observe the xylem tubes in the celery as the colored water moves through the celery

2. Have students draw, label and color the parts of a plant. These should be displayed in the classroom or hall .

3. Each student brings an example of a herbaceous or woody stem to show and explain.

4. Observe classroom plants and the phototropism toward a light source (Place in a window, if possible)

The parts of the plant that you rarely see is the root. Where are most roots found? (Underground) Even though roots are usually underground they are of great importance to a plant.

The purposes of roots include:

1. Anchor plant in ground

2. Absorb, store and transport water and minerals for the plant

3. Grow downward due to the pull of gravity

The first root to develop on a plant is the primary root. Any root branching from this first root is called a secondary root. The microscopic roots that actually do the diffusion and osmosis of material are the root hairs.

Xylem cells make up the tissues called xylem tubes. These vascular tubes conduct water and minerals up the plant from the ground here the water and minerals are taken in. Phloem cells make up phloem tubes which bring substances down through the plant (example- glucose made in leaves travels down to other plant parts through phloem)

(Do the activity using celery and colored water. Have students observe the different types of roots.)

The stem is another very important part of the plant. Some of the purposes of stems are as follows:

1. Support leaves and hold them up toward the light (ask-why? The stem allows the maximum exposure of the leaves to light.)

2. Some stems can produce food (example - broccoli, celery . . .)

3. Stems move water, food, minerals up and down the plant

4. Some store food

There are two types of stems, herbaceous and woody. The herbaceous stem are soft, green in color and flexible. The herbaceous stems are usually found on plants that live only one year. Examples would be the stems of a tomato plant. (Show example-most house plants have herbaceous stems.)

The woody stem is a hard stem that is dry on the outside. This type of stem is designed to last several years and to withstand extreme changes in temperature. (Show woody stems such as small branches and twigs from trees or shrubs)

There are some stems that are very different. Most of us are not aware that these unusual structures are actually stems. The potato tuber is an underground stem that stores a great amount of food . (show potato) Another underground stem is the rhizome of Bermuda grass and Johnson grass. Ask students if they have ever had to pull grass from flower beds or crop fields.)

The leaf is defined as the "food factory" of the plants. This is where most of the photosynthesis occurs in the plants. (Have students draw and label the cross-section of a leaf.)

The layers you drew and labeled as palisade layer and spongy layer are the two layers that contain chlorophyll. Chlorophyll is the green pigment in plant that is involved in the process of photosynthesis. The tiny openings of labeled stomata are the openings where gases enter (H₂0, O₂, C0₂) and leave (H₂0, O₂) the plant.

The process of photosynthesis is a very complex chemical process. We are going to draw and learn a simplified version. You will be able to trace the sunlight which is trapped in the glucose molecule. You will understand how carbon dioxide is used and how oxygen is produced. Have the students draw the process.)

The chemical formula for photosynthesis is:

6C0₂ + 6H₂0--------light/chlorophyll--> C6H₁₂0₆ + 6O₂ + 6H₂0

The plant needs light, warm- temperature, C0₂, water, minerals, and chlorophyll. The high energy glucose that is produced is used by plants and animals as the energy source to sustain life. The oxygen produced and given off as a waste product is used by animals and other life structures.

Photosynthesis Respiration

Purpose to produce glucose to release energy

Needed C0₂, H₂0, C6H₁₂0₆, O₂

Sunlight, Chlorophyll

Waste O₂, CO₂

When Daylight 24 hrs a day

Plant behavior is very different from the behavior exhibited by consuming animals. Plant behavior is known as tropism. These tropism are a plants response to a stimulus in the environment. One of the most widely known tropism in plants is the phototropism - a plant's response to light. The plant will turn it's leaves toward the light . (Show classroom plants.) Other common tropism observed in plants are hydrotropism - growth toward water, and geotropism - growth with or against gravity.

Plants do not have sense organs, muscular systems or nervous systems. Tropism are controlled by plant hormones called auxins.

We have studied and drawn pictures about the plant kingdom. We have examined and observed the various systems found in plants. We have learned that plants show different types of behavior.

KEY QUESTIONS (CHALLENGE QUESTIONS):

1. Can you plant a seed upside down? (No) Why not? (Gravity)

2. What part of your circulatory system is similar to a plants root hairs? (Capillaries)

3. Why are leaves arranged around a stem instead of in a line up and down the stem? (So each leaf can receive light and not be shaded by other leaves.)

4. Why is chlorophyll called an enzyme? (It speeds up the chemical changes occurring in photosynthesis.)

auxins - plant hormones that control tropism

diffusion - movement of materials from an area of high concentration to an area of low concentration

flexible - soft, elastic

herbaceous - stems that are soft and green

osmosis - movement of water through a membrane

palisade layer - layer of cells in a leaf that contain chlorophyll

phloem - tubes that carry food made by plant

primary root - first root to develop from a seed

rhizome - underground stem

root hair - microscopic roots that undergo diffusion and osmosis with materials

secondary roots - roots branching from primary roots

spongy layer - layer of cells containing chlorophyll

stomata - openings on underside of leaves

tropism - responses made by plants

tuber - underground stem

woody - stems that are hard and dry

xylem - tubes that carry water and minerals

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