LESSON PLAN

Name(s): Audrey De Zeeuw 

Title of Lesson: Plant "eating"

Date of Lesson: TBD

Length of Lesson: 50 minutes

Description of the Class:

Name: Biology

Grade Level: Ninth

Source of the Lesson:

Biology: The Book of Life, Spring 2003, Stony Point High School

TEKS Addressed:

(13) Science concepts. The student knows the significance of plants in the environment. The student is expected to:

(A) evaluate the significance of structural and physiological adaptations of plants to their environments; and

(B)survey and identify methods of reproduction, growth, and development of various types of plants

I. Overview

This lesson will have students make generalizations, identify and label about root structures and then relate their form to their function.

II. Performance Objectives

The student will be able to:

-identify and label parts of a root tissue

-describe the functions of the root tissues

-explain the functions of stem tissues

-identify how plants obtain and transport nutrients

III. Resources, Materials, and Supplies Needed

IV. Safety Considerations

 Students should not eat the plants, use caution when using the iodine stain, and the teacher should take care with the razor blade

V. Supplementary Materials, Handouts

Five E Organization

Teacher Does Student Does

Engage: Learning Experience Students will be given a parsnip root. They will be told to think about how that plant obtains its nutrients.  Questions How does a plant eat? In other words, the plant needs to obtain its nutrients as well. We know that plants needs soil rich in nutrients, but just how does that plant obtain its nutrients?  They don't have blood so how do nutrients get from place to place?

Hoped for student response: Students will be examine the root in detail and carefully consider the how the plant eats. Expected student responses A plant uses its root and stem system to obtain nutrients. Xylem and Phloem are two tissues in the plant that transport water and starch which are necessary for the plant to survive. It is through capillary action that the plants transport the nutrients through these tissues.

Evaluate

Explore: Learning Experience(s): Students will use a prepared cross section of a parsnip root that has been stained with iodine. They will prepare the root for microscopic viewing using the iodine stain. The students will then examine the root under a microscope and observe the tissues of a root section. Questions Which portions of the root did the iodine stain? We know the iodine stains starch, what does this say about the plant structure? Do you see a pattern amongst the vascular tissues? What do you think these tissues are used for?

Hoped for student response:  The students will sketch the structure they see under the microscope and make precise observations. Expected student responses The phloem is stained blue and is most likely the where starch is transported through the plant. There is a pattern amongst the tissue, alternating bands of xylem and phloem. The diameter or these tissues also varies as well. These tissues are used for plant transportation of water and nutrients. This is how the plant "eats".

Evaluate 

Explain: Learning Experience(s) The students will examine a picture of a tree and attempt to figure out how old the tree is through dendochronology (counting the rings of a tree to determine its age).  Questions Why do you think the rings of a tree are accurate descriptions for the age of a tree? What do you think each set of rings represents?

Hoped for student response   The students observe a cross section of a tree trunk and accurately count the rings. Expected student responses The rings are accurate describtions of the age of the tree because the rings are made of xylem. Pith is found at the center of the tree stem followed by the xylem, which makes up the majority of the trees circumference. The cambium layer keeps the xylem separated from the rough bark. Each spring or summer a new layer of xylem is formed, producing the rings we can count. A tree ring is a layer of wood cells produced by a tree in one year, consisting of thin walled cells formed in the early growing season (called earlywood), and thicker walled cells that are produced later in the growing season (called latewood).

Evaluate

Extend/Elaborate: Annual rings vary in thickness due to environmental factors. What kinds of environmental factors during the year might influence tree growth? Suppose that during a ten-year period rainfall in a region increased each spring by ten percent. During the next ten-year period, rainfall decreased each spring by ten percent in the same region. What effect do you think this weather pattern would have on the annual rings of a 20-year old tree?

Hoped for student response: The students will think critically about the question and work in groups to answer these extended thought questions. Expected student responses The climate might affect tree growth, as well as rainfall amount, slope gradient, temperature, wind, the amount of sun and snow accumulation. The tree with varying rainfalls will have xylem that is smaller in diameter for the drought period and larger xylem when the tree received more rain. The rings would respectively be thinner and thicker.