Seeds & Trees Lesson Plans

• Classifying Leaves
• Seed Germination Inquiry
• Observing Seed Germination Between a Monocot and a Dicot
• Effects of Toxins on Seed Germination
• Effects of Toxins on Plant Growth

*CLASSIFYING LEAVES

Introduction

Over the centuries, people who study the natural world have tried to sort or classify organisms into groups whose members show a logical relationship to each other. The science of classification is called taxonomy. One of the products of taxonomy is the development of dichotomous keys. A dichotomous key is an organized list of characteristics that can be used to identify organisms. Such keys have been made for almost every group of organisms in the world.

Objectives

• Identify structural characteristics of leaves
• Identify differences between leaves
• Write a dichotomous key based on the characteristics of leaves

Materials

• several different types of leaves

Procedure

1. Notice several different types of leaves are presented on the lab tables. Each type of leaf is labeled with a different Genus.
2. Record observations for each Genus according to the following characteristics.

Leaf Characteristics

edge of leaves

• smooth
• toothed and jagged

number of leaflets

• simple
• compound

lobes of leaves

• pinnate
• palmate
• not lobed

pattern of veins

• parallel
• pinnate (feather veined)
• palmate (fan veined)

There are several ways you could write a key for these leaves. Remember, the key that you write should make it possible for anyone to identify the leaves, and all steps should contain two contrasting statements.

Use the leaf characteristics to write the opposite statements for each step. If a statement in any step leads you to more than one leaf you will need more steps to separate those leaves into more specific groups.

If a statement in any step leads you to only one leaf, you have identified that leaf. Write the Genus name of the plant. When you have identified and written in the names of all of the plants you have finished your key. Use the beginning of this key to help get you started.

1a. leaves simple................go to Step 2
1b. leaves compound..............go to Step 3
2a. ..................
2b. ..................
3a. ..................
3b. ..................(keep going!)

To check your key, select one of the leaves and see if your key leads you to the correct identity.

You may wish to use this leaf identification site.

SEED GERMINATION INQUIRY

Introduction

In order to germinate, seeds need a combination of 3 things. It is your job to investigate just what is necessary in order for a seed to grow.

Objectives

• Identify by scientific investigation the 3 necessary components of seed germination.

Materials

NOTE These materials will be available to you. They may or may not be helpful in your investigation.

• corn seeds
• pea seeds
• petri dishes
• paper towels
• plastic bags
• soil
• light
• fertilizer
• Anything else? Let me know.

Hypothesis

State your hypothesis.

Prodecure

Write a step by step procedure stating how you intend to test your hypothesis.

Observations

Note at least 5 consecutive daily observations for each part of your hypothesis you intend to test.

Results

Create a data table which organizes your results.

Concslusions

State your conclusions. Do they support your hypothesis?

**OBSERVING SEED GERMINATION OF A MONOCOT AND DICOT

Introduction

The purpose of this lab is to observe the process of germination and growth in a monocot and a dicot seed. As you make daily observations, you will observe several differences between monocot seeds and dicot seeds.

Objectives

• Identify with scientific observation differences between monocots and dicots.

Materials

• monocot seeds / corn seeds
• dicot seeds / pea seeds
• petri dish
• paper towels
• ziplock bags

Procedure

1. Construct a germination chamber.
1. Obtain a petri dish and 8-10 layers of paper towels.
2. Cut the paper towels to fit neatly inside the petri dish.
3. Water your germination chamber so that all layers of the paper towel are wet.
4. Place your seeds on the paper towel. Make sure they are not covered with water.
5. Place the cover on your petri dish. Notice that it is not air-tight.
6. Set in a warm place.
7. Water when necessary.
2. Observations must be made daily. You should make 10 total observations.
3. Daily observations should be recorded in a table which includes: date of observation, written descriptions and labeled drawings.
4. If your plants begin to outgrow your petri dish simply cover with a ziplock bag.

Observations

Create a data table to organize your observations.

Conclusions

Fully explain the differences you found between the germination of monocot seeds and dicot seeds.

*EFFECTS OF TOXINS ON SEED GERMINATION

Introduction

The life of a plant begins in the seed. A seed contains the embryo of a single plant and enough food for the first stages of germination. The dry seed is dormant, like some trees during the winter, and will remain in this state until it is stimulated by the presence of specific conditions. In order to germinate a seed must have a combination of 3 things: moisture, oxygen and warm temperature. Toxins may effect the ability of the seed to start growing. Such are the warnings to pregnant mothers especially during the first months of gestation. In this lab you will test the effect of toxins on embryonic seed development and infer the effects of toxins on human embryonic development.

Materials

• 8 seeds
• 4 plastic sandwich bags
• paper towels
• filtered tobacco water
• aspirin water
• coffee
• water
• graduated cylinder

Hypothesis

State a hypothesis

Procedure

1. Contruct 4 germination chambers; 2 seeds each
1. Obtain plastic bags and 8-10 layers of paper towels.
2. Cut the paper towels to fit neatly inside the bags.
3. Water your germination chamber so that all layers of the paper towel are wet.
4. Place seeds on the paper towel. Make sure they are not covered with water.
5. Do not fold the plastic bag closed.
6. Set in a warm place.
2. Label each germination chamber with its treatment. (i.e. water, coffee, aspirin, tobacco.)
3. Use 20ml of specific treatments to water your seeds daily.
4. Observations must be made daily. You should make 10 total observations.
5. Daily observations should be recorded in a table which includes: date of observation and written descriptions.

Observations

Create a data table to organize your observations.

Conclusions

Fully explain the results of your experiment. Do your results support you hypothesis? Infer what may happen if a woman ingests these same toxins during the first months of pregnancy.

EFFECTS OF TOXINS ON CELLULAR GROWTH

Introduction

We have all been told that children should not drink coffee because it will stunt their growth. The Surgeon General warns us that cigarettes are harmful. Drugs such as aspirin should be "taken as directed." You will run a controlled experiment determining just what effects these substances have on plant growth directly. Then you will infer the effects of these same toxins on the cellular growth in animals.

Objectives

• Explain the detrimental effects of a toxin on plant cell growth and draw a conclusion as to what effect these may have on animal cell growth.

Hypothesis

Choose one substance you wish to test and state a hypothesis.

Materials

• germinated seeds
• small pots
• moist potting soil
• water
• one toxin
• tobacco water
or
• coffee water
or
• aspirin water
• ruler
• graduated cylinder

Procedure

You must write a step by step procedure by which you will test your hypothesis. Remember your experiment must contain a controlled variable and measurable results that you can graph.

Observations

Create a data table to organize at least 10 daily observations.

Results

Create a graph based on your observations

Conclusions

Fully explain the results as depicted by your graph. Do your results support your hypothesis? What implications do your results have in regard to toxins and cellular growth in animals?