Science
Strand III
Use Scientific Knowledge from the Life Sciences in Real-World Contexts

 

Science/Strand III
Content Standard 2
All students will use classification systems to describe groups of living things; compare and contrast differences in the life cycles of living things; investigate and explain how living things obtain and use energy; and analyze how parts of living things are adapted to carry out specific functions. (Organization of Living Things)

 

Science/Strand III/Content Standard 2
Middle School

 

Science/Strand III/Content Standard 2/Middle School
Benchmark 3
Describe the evidence that plants make and store food.

Benchmark Clarification

Students have misconceptions about food energy. Food provides the energy and raw materials needed for cell functions. Plants go through a special “food-making” process called photosynthesis.

Students will:

  • Observe chloroplasts in special plant cells
  • Determine the location in specialized plant cells where photosynthesis occurs

Explain that during photosynthesis certain raw materials (carbon dioxide and water) are taken in and chemically combined to form new products (sugar and oxygen)

  • Recognize that the sun’s light energy is converted and stored as chemical energy in food; this food may be used immediately or stored as starch for later use
  • Examine various food storage organs (e.g., potatoes, onions, carrots)

Key Concept / Real World Context / Instructional Example / Assessment Example / Resources

 

Science/Strand III/Content Standard 2/Middle School/Benchmark 3
Key Concept
Process and products of food production and transport:

  • photosynthesis
  • starch
  • sugar
  • oxygen
  • carbon dioxide
  • water

See Use of food for energy (SCI.III.2.MS.4).

 

Science/Strand III/Content Standard 2/Middle School/Benchmark 3
Real World Context
Plant food storage organs:

  • potato
  • onion

Starch storage in plants grown under different conditions

 

Science/Strand III/Content Standard 2/Middle School/Benchmark 3
Instructional Example

Benchmark Question: How do living things obtain and use energy?

Focus Question: What evidence is there that plants make and store food?

Students will:

  • Observe chloroplasts in special plant cells by looking at plant leaves under a microscope. (If needed, prepared slides may be used to help students in locating the chloroplasts.)
  • Draw a diagram of what they observe under the microscope.
  • Discuss their data and observations with others to determine the location of specialized plant cells where photosynthesis occurs.

The teacher will explain the following:

  • During photosynthesis, certain raw materials (carbon dioxide + water) are taken in and chemically combined in the chloroplast to form new products (sugar and oxygen).
  • The plant then uses the sugar immediately as food or stores it as starch in a special food storage organ.

In order to develop an understanding of how plants store food, students will examine various food storage organs (e.g., potatoes, onions, carrots). They will conduct a simple iodine/starch test to discover that the storage organ is a vessel that plants use to store food energy.

A simple iodine starch test involves dropping iodine solution on a piece of food. Initially, iodine appears reddish-brown in color. When iodine comes in contact with starch, it turns to a bluish-black indicating the presence of starch.

Then, students will participate in a guided discussion of the food storage organs:

1. What happens to a food storage organ in your cupboard? (Gets smaller, starts to grow sprouts, develops brown spots.)

2. Why is this happening? (It is losing water, growing roots, decomposing [chemical change.])

3. Where is it getting the energy to grow sprouts? (From the food energy stored within the cells of the storage organ.)

Students will design an investigation to test their hypothesis about what is happening to their potato, onion, or carrot.

Follow up with a discussion and presentation of data from the investigations.

End the lesson with a “Did You Know…” i.e., Native Americans in South and Central America first cultivated many tuber plants, like the potato. One of these plants has erroneously been called the Irish potato. Its fried version is called French fries. Ask the students to talk about what observations they can make from this interesting story.

Constructing: (SCI.I.1.MS.1), (SCI.I.1.MS.2), (SCI.I.1.MS.3), (SCI.I.1.MS.6).

Reflecting: (SCI.II.1.MS.1), (SCI.II.1.MS.5).

 

Science/Strand III/Content Standard 2/Middle School/Benchmark 3
Assessment Example

Students will respond to the following scenario and justify their answers based on their knowledge of the food-making process and food storage organs of plants.

The agricultural company Potatoes R Us claims that growing potatoes in a high CO2 atmosphere will produce bigger crops. If potatoes are grown under two different concentrations of CO2, then what is the best evidence to determine which potato plants are making and storing more food?

A. Amount of CO2 produced by plants

B. Size of potatoes

C. Amount of oxygen used by plants

D. How long it takes for seeds to germinate

Select the best answer. Write a letter to the company, Potatoes R US, citing at least two pieces of scientific evidence that would support your answer.

(Give students rubric before activity.)

Scoring Rubric

Criteria

Apprentice

Basic

Meets

Exceeds

Correctness of answer

Selects correct answer (B, size of potatoes).

Selects correct answer (B, size of potatoes).

Selects correct answer (B, size of potatoes).

Selects correct answer (B, size of potatoes).

Accuracy of justification

Fails to give an accurate reason for that answer.

Gives only one accurate scientific reason to justify that answer.

Gives two accurate scientific reasons to justify that answer.

Gives several detailed scientific reasons to justify that answer.

 

Science/Strand III/Content Standard 2/Middle School/Benchmark 3
Resources

Webliography

Webliography.
http://mtn.merit.edu/mcf/SCI.III.2.MS.3.html

“Basic Needs,” GrowLab: Activities for GrowingMinds.
http://www.kidsgardening.com/

The Budding Botanist. AIMS.
http://wwws.aimsedu.org/aimscatalog/default.tpl

http://chem.lapeer.org/Bio1Dos/Index.html

“The Eyes Have It,” GrowLab: Activities for Growing Minds.
http://www.kidsgardening.com/

The Lives of Plants. NEW DIRECTIONS UNIT.
http://www.BCMSC.k12.mi.us/