1. Diversity of Life Investigation 5:Seeds of Life

2. At the end of Investigation 5 you will be able to:
Describe the structure and function of seeds and roots.
Define germination.
Make and record accurate observations using correct vocabulary throughout the investigation.

3. Investigation 5 - Part 1 Lima Bean Dissection

4. Teacher Reminder: We will plant one of these seeds.
What could you do to these dry bean seeds to get more evidence as to whether they are living or nonliving?
Teacher Reminder: We will plant one of these seeds.

5. Lab Notebook page 30
Materials: dry lima bean, wet lima bean, dissecting tool (paper clip), tweezers, hand lens, paper towels.
Procedure: DRY SEED DISSECTION
Draw the outline of the seed.
On the paper towel, chip the seed coat off with the paperclip
Carefully split the seed in half
Observe with a hand lens and draw what you see.

6. Two of the Seed Structures
Seed Coat- the tough, almost airtight layer on the outside of the seed.
Cotyledon- the two large, white, ear-shaped parts of the seed. The cotyledon is composed of endosperm, a starchy material that supplies food to the plant as it starts to grow.
Note: Seeds that separate in two halves are called dicots. The lima bean is a dicot. Seeds that have only one cotyledon are monocots.

7. Another Seed Structure
Embryo- the baby plant.
The embryo may have tiny developing leaves and a stem and root that can be seen with a hand lens. The embryo is alive, but has been in a state of suspended development, waiting for the right growing conditions.

8. PLANT EMBRYO

9. WET SEED DISSECTION Before we review questions 2 and 3:
How are the wet and they dry seed similar?
How are they different?
Let’s review the last 2 questions now.

10. Think: What survival value is there in producing
GERMINATION
Germination- when a seed starts to grow, we say they have germinated. Conditions have to be just right for a seed to germinate. It has to have oxygen and water.
A dormant seed is protected against desiccation and predation
Think: What survival value is there in producing
seeds that are dormant?

11. SEED DIVERSITY DATABASE

12. Investigation 5 - Part 2 Sprouting Monocots and Dicots

13. Think: What happens next? How can we find out?
When a seed germinates, it starts to grow and develop. We saw that the seed coat wrinkles up and splits open, and we saw the cotyledons and the embryo inside.
Think:
What happens next?
How can we find out?

14. New seeds
These are small seeds. Because we want to observe each step in the germination process, we don’t want to lose them in a cup of soil. It makes sense to sprout them on paper in a petri dish.
Show students the rye grass and radish seeds on an overhead projector.

15. Minisprouter Preparation
A. Fold a paper towel into quarters
B. Trace around the smaller half of the petri dish.
C. Cut out four circles.
D. Fold 3 of the circles in half and put them into the larger half of the petri dish.
E. Cover the folded circles with one the unfolded circles.
F. Dampen the paper towels with spring water.

16. Planting Schedule 1. Each group of four will break into pairs.
2. One pair will plant 6-7 rye grass seeds on the paper towel shelf.
3. The other set of partners in that group will plant 4-5 radish seeds on the paper towel shelf.
4. Put the smaller part of the petri dish on top and secure with two small pieces of tape.
5. Label with your initials and your table # with grease pencil.
6. Place in the correct class container.

17. Please record the day 1 information on page 31 of your lab notebook.
When you have recorded this information, please place your sprouter in the chamber.
In order to simulate the conditions that seeds experience under ground, we will cover the seeds to keep them in the dark. We will only expose them to light when we make our observations.
After students have placed their seeds in the chamber, ask them if they placed the seeds right side up? Some students might panic and say they are not sure.

18. Please preview the questions on page 33 of your lab notebook so that you know what you are listening for as we view The Secret Garden. Multitask: Take notes during the film.

19. SPROUTER OBSERVATIONS
At each table, please remove one radish seed and one rye grass seed for close observation. Record your observations on page 31.

20. YOUR CHOICE
In nature, when sprouting seeds are about the size of your sprouts, they might be pushing up above the soils surface. Decide whether your group would like to return your minisprouter to the dark chamber, or leave it out in the light.

21. Where are the seeds now? DISCUSSION QUESTIONS
Have there been any changes since yesterday?
Are any seedlings growing upside down,
with their root going up and their shoot going down?
Where are the seeds now?

22. Cotyledons- Important Seed Structures
The cotyledons provide the energy for germination.
Grasses are monocots. Their cotyledon stays underground to nourish the sprout.
Radishes are dicots. The two cotyledons come above ground and look a lot like leaves.

23. Roots- Important Plant Structures
Can you think of any reason why the root comes out of the seed first during germination? Think: What could we do to learn more about the structure of the roots?

24. Investigation 5 - Part 3 Root Cells

25. How do the seeds in the light compare to those that remained in the dark?
Have you ever seen green color in plants before? Of course you have!
If we observed the green cotyledon under the microscope, what would you expect to see?

26. The green color is the chlorophyll that developed in the cotyledons when the light fell on the plants. Chlorophyll is an important pigment that captures sunlight energy and stores it in the sugar glucose. The plant can then use that glucose for energy!

27. Root-Tip Slide Preparation
Each lab group will be making two slides- one rye grass root and one radish root.
slide preparation instructions
Record your observations on page 35.

28. Labeling
Please label the parts of the root using the transparency as a guide.
The root tip is actively growing. The cells are dividing rapidly and pushing the root down into the soil.
How do the cells of the root tip compare the those in the zone of elongation?
These longer cells are forming into channels through which water can flow!
These longer cells are forming into channels through which water can flow!

29. Look closely at the root hairs in the Zone of Maturation
Look closely at the root hairs in the Zone of Maturation. These are extensions of the root cells that act like little straws to take in water.
Do you think that these channels
are only in the root?
If these channels extend through the entire plant, what function do you think they serve?
How could we observe the movement of water in this plant?

30. We will place this celery in a vial of water and check in on it periodically.
SELF-ASSESSMENT
Please take a look at page 34 of your lab notebook and make any changes to your responses that you think are necessary.

31. Debrief
In Cornell Notes, review key points and root parts. Please read Seeds and Roots in your resource text and build a comprehensive concept map to delineate the content into relationships.